Sync to upstream/release/513 (#340)

Analysis/include/Luau/Error.h

@@ -285,12 +285,12 @@ struct TypesAreUnrelated
     bool operator==(const TypesAreUnrelated& rhs) const;
 };
 
-using TypeErrorData = Variant<TypeMismatch, UnknownSymbol, UnknownProperty, NotATable, CannotExtendTable, OnlyTablesCanHaveMethods,
+using TypeErrorData =
-    DuplicateTypeDefinition, CountMismatch, FunctionDoesNotTakeSelf, FunctionRequiresSelf, OccursCheckFailed, UnknownRequire,
+    Variant<TypeMismatch, UnknownSymbol, UnknownProperty, NotATable, CannotExtendTable, OnlyTablesCanHaveMethods, DuplicateTypeDefinition,
-    IncorrectGenericParameterCount, SyntaxError, CodeTooComplex, UnificationTooComplex, UnknownPropButFoundLikeProp, GenericError,
+        CountMismatch, FunctionDoesNotTakeSelf, FunctionRequiresSelf, OccursCheckFailed, UnknownRequire, IncorrectGenericParameterCount, SyntaxError,
-    CannotCallNonFunction, ExtraInformation, DeprecatedApiUsed, ModuleHasCyclicDependency, IllegalRequire, FunctionExitsWithoutReturning,
+        CodeTooComplex, UnificationTooComplex, UnknownPropButFoundLikeProp, GenericError, CannotCallNonFunction, ExtraInformation, DeprecatedApiUsed,
-    DuplicateGenericParameter, CannotInferBinaryOperation, MissingProperties, SwappedGenericTypeParameter, OptionalValueAccess, MissingUnionProperty,
+        ModuleHasCyclicDependency, IllegalRequire, FunctionExitsWithoutReturning, DuplicateGenericParameter, CannotInferBinaryOperation,
-    TypesAreUnrelated>;
+        MissingProperties, SwappedGenericTypeParameter, OptionalValueAccess, MissingUnionProperty, TypesAreUnrelated>;
 
 struct TypeError
 {

Analysis/include/Luau/LValue.h

@@ -4,7 +4,6 @@
 #include "Luau/Variant.h"
 #include "Luau/Symbol.h"
 
-#include <map> // TODO: Kill with LuauLValueAsKey.
 #include <memory>
 #include <unordered_map>
 
@@ -38,24 +37,13 @@ std::optional<LValue> tryGetLValue(const class AstExpr& expr);
 // Utility function: breaks down an LValue to get at the Symbol, and reverses the vector of keys.
 std::pair<Symbol, std::vector<std::string>> getFullName(const LValue& lvalue);
 
-// Kill with LuauLValueAsKey.
-std::string toString(const LValue& lvalue);
-
 template<typename T>
 const T* get(const LValue& lvalue)
 {
     return get_if<T>(&lvalue);
 }
 
-using NEW_RefinementMap = std::unordered_map<LValue, TypeId, LValueHasher>;
+using RefinementMap = std::unordered_map<LValue, TypeId, LValueHasher>;
-using DEPRECATED_RefinementMap = std::map<std::string, TypeId>;
-
-// Transient. Kill with LuauLValueAsKey.
-struct RefinementMap
-{
-    NEW_RefinementMap NEW_refinements;
-    DEPRECATED_RefinementMap DEPRECATED_refinements;
-};
 
 void merge(RefinementMap& l, const RefinementMap& r, std::function<TypeId(TypeId, TypeId)> f);
 void addRefinement(RefinementMap& refis, const LValue& lvalue, TypeId ty);

Analysis/include/Luau/Substitution.h

@@ -55,6 +55,8 @@
 namespace Luau
 {
 
+struct TxnLog;
+
 enum class TarjanResult
 {
     TooManyChildren,
@@ -89,6 +91,10 @@ struct Tarjan
 
     int childCount = 0;
 
+    // This should never be null; ensure you initialize it before calling
+    // substitution methods.
+    const TxnLog* log;
+
     std::vector<TypeId> edgesTy;
     std::vector<TypePackId> edgesTp;
     std::vector<TarjanWorklistVertex> worklist;

Analysis/include/Luau/TxnLog.h

@@ -72,6 +72,9 @@ struct PendingType
     }
 };
 
+std::string toString(PendingType* pending);
+std::string dump(PendingType* pending);
+
 // Pending state for a TypePackVar. Generated by a TxnLog and committed via
 // TxnLog::commit.
 struct PendingTypePack
@@ -85,6 +88,9 @@ struct PendingTypePack
     }
 };
 
+std::string toString(PendingTypePack* pending);
+std::string dump(PendingTypePack* pending);
+
 template<typename T>
 T* getMutable(PendingType* pending)
 {
@@ -237,7 +243,7 @@ struct TxnLog
 
     // Follows a type, accounting for pending type states. The returned type may have
     // pending state; you should use `pending` or `get` to find out.
-    TypeId follow(TypeId ty);
+    TypeId follow(TypeId ty) const;
 
     // Follows a type pack, accounting for pending type states. The returned type pack
     // may have pending state; you should use `pending` or `get` to find out.

Analysis/include/Luau/TypeInfer.h

@@ -262,7 +262,7 @@ public:
      *     {method: ({method: (<CYCLE>) -> a}) -> a}
      *
      */
-    TypeId instantiate(const ScopePtr& scope, TypeId ty, Location location);
+    TypeId instantiate(const ScopePtr& scope, TypeId ty, Location location, const TxnLog* log = TxnLog::empty());
 
     // Replace any free types or type packs by `any`.
     // This is used when exporting types from modules, to make sure free types don't leak.
@@ -308,9 +308,15 @@ private:
     TypeId singletonType(bool value);
     TypeId singletonType(std::string value);
 
+    TypeIdPredicate mkTruthyPredicate(bool sense);
+
     // Returns nullopt if the predicate filters down the TypeId to 0 options.
     std::optional<TypeId> filterMap(TypeId type, TypeIdPredicate predicate);
 
+public:
+    std::optional<TypeId> pickTypesFromSense(TypeId type, bool sense);
+
+private:
     TypeId unionOfTypes(TypeId a, TypeId b, const Location& location, bool unifyFreeTypes = true);
 
     // ex
@@ -349,7 +355,6 @@ private:
     void refineLValue(const LValue& lvalue, RefinementMap& refis, const ScopePtr& scope, TypeIdPredicate predicate);
 
     std::optional<TypeId> resolveLValue(const ScopePtr& scope, const LValue& lvalue);
-    std::optional<TypeId> DEPRECATED_resolveLValue(const ScopePtr& scope, const LValue& lvalue);
     std::optional<TypeId> resolveLValue(const RefinementMap& refis, const ScopePtr& scope, const LValue& lvalue);
 
     void resolve(const PredicateVec& predicates, ErrorVec& errVec, RefinementMap& refis, const ScopePtr& scope, bool sense, bool fromOr = false);

Analysis/include/Luau/TypedAllocator.h

@@ -6,8 +6,6 @@
 #include <vector>
 #include <memory>
 
-LUAU_FASTFLAG(LuauTypedAllocatorZeroStart)
-
 namespace Luau
 {
 
@@ -22,10 +20,7 @@ class TypedAllocator
 public:
     TypedAllocator()
     {
-        if (FFlag::LuauTypedAllocatorZeroStart)
         currentBlockSize = kBlockSize;
-        else
-            appendBlock();
     }
 
     ~TypedAllocator()
@@ -64,18 +59,12 @@ public:
 
     bool empty() const
     {
-        if (FFlag::LuauTypedAllocatorZeroStart)
         return stuff.empty();
-        else
-            return stuff.size() == 1 && currentBlockSize == 0;
     }
 
     size_t size() const
     {
-        if (FFlag::LuauTypedAllocatorZeroStart)
         return stuff.empty() ? 0 : kBlockSize * (stuff.size() - 1) + currentBlockSize;
-        else
-            return kBlockSize * (stuff.size() - 1) + currentBlockSize;
     }
 
     void clear()
@@ -84,10 +73,7 @@ public:
             unfreeze();
         free();
 
-        if (FFlag::LuauTypedAllocatorZeroStart)
         currentBlockSize = kBlockSize;
-        else
-            appendBlock();
     }
 
     void freeze()

Analysis/include/Luau/Unifier.h

@@ -51,6 +51,10 @@ struct Unifier
 
 private:
     void tryUnify_(TypeId subTy, TypeId superTy, bool isFunctionCall = false, bool isIntersection = false);
+    void tryUnifyUnionWithType(TypeId subTy, const UnionTypeVar* uv, TypeId superTy);
+    void tryUnifyTypeWithUnion(TypeId subTy, TypeId superTy, const UnionTypeVar* uv, bool cacheEnabled, bool isFunctionCall);
+    void tryUnifyTypeWithIntersection(TypeId subTy, TypeId superTy, const IntersectionTypeVar* uv);
+    void tryUnifyIntersectionWithType(TypeId subTy, const IntersectionTypeVar* uv, TypeId superTy, bool cacheEnabled, bool isFunctionCall);
     void tryUnifyPrimitives(TypeId subTy, TypeId superTy);
     void tryUnifySingletons(TypeId subTy, TypeId superTy);
     void tryUnifyFunctions(TypeId subTy, TypeId superTy, bool isFunctionCall = false);

Analysis/src/BuiltinDefinitions.cpp

@@ -8,6 +8,8 @@
 
 #include <algorithm>
 
+LUAU_FASTFLAG(LuauAssertStripsFalsyTypes)
+
 /** FIXME: Many of these type definitions are not quite completely accurate.
  *
  * Some of them require richer generics than we have.  For instance, we do not yet have a way to talk
@@ -391,6 +393,34 @@ static std::optional<ExprResult<TypePackId>> magicFunctionAssert(
 {
     auto [paramPack, predicates] = exprResult;
 
+    if (FFlag::LuauAssertStripsFalsyTypes)
+    {
+        TypeArena& arena = typechecker.currentModule->internalTypes;
+
+        auto [head, tail] = flatten(paramPack);
+        if (head.empty() && tail)
+        {
+            std::optional<TypeId> fst = first(*tail);
+            if (!fst)
+                return ExprResult<TypePackId>{paramPack};
+            head.push_back(*fst);
+        }
+
+        typechecker.reportErrors(typechecker.resolve(predicates, scope, true));
+
+        if (head.size() > 0)
+        {
+            std::optional<TypeId> newhead = typechecker.pickTypesFromSense(head[0], true);
+            if (!newhead)
+                head = {typechecker.nilType};
+            else
+                head[0] = *newhead;
+        }
+
+        return ExprResult<TypePackId>{arena.addTypePack(TypePack{std::move(head), tail})};
+    }
+    else
+    {
         if (expr.args.size < 1)
             return ExprResult<TypePackId>{paramPack};
 
@@ -398,6 +428,7 @@ static std::optional<ExprResult<TypePackId>> magicFunctionAssert(
 
         return ExprResult<TypePackId>{paramPack};
     }
+}
 
 static std::optional<ExprResult<TypePackId>> magicFunctionPack(
     TypeChecker& typechecker, const ScopePtr& scope, const AstExprCall& expr, ExprResult<TypePackId> exprResult)

Analysis/src/LValue.cpp

@@ -5,8 +5,6 @@
 
 #include <vector>
 
-LUAU_FASTFLAG(LuauLValueAsKey)
-
 namespace Luau
 {
 
@@ -94,17 +92,7 @@ std::pair<Symbol, std::vector<std::string>> getFullName(const LValue& lvalue)
     return {*symbol, std::vector<std::string>(keys.rbegin(), keys.rend())};
 }
 
-// Kill with LuauLValueAsKey.
+void merge(RefinementMap& l, const RefinementMap& r, std::function<TypeId(TypeId, TypeId)> f)
-std::string toString(const LValue& lvalue)
-{
-    auto [symbol, keys] = getFullName(lvalue);
-    std::string s = toString(symbol);
-    for (std::string key : keys)
-        s += "." + key;
-    return s;
-}
-
-static void merge(NEW_RefinementMap& l, const NEW_RefinementMap& r, std::function<TypeId(TypeId, TypeId)> f)
 {
     for (const auto& [k, a] : r)
     {
@@ -115,45 +103,9 @@ static void merge(NEW_RefinementMap& l, const NEW_RefinementMap& r, std::functio
     }
 }
 
-static void merge(DEPRECATED_RefinementMap& l, const DEPRECATED_RefinementMap& r, std::function<TypeId(TypeId, TypeId)> f)
-{
-    auto itL = l.begin();
-    auto itR = r.begin();
-    while (itL != l.end() && itR != r.end())
-    {
-        const auto& [k, a] = *itR;
-        if (itL->first == k)
-        {
-            l[k] = f(itL->second, a);
-            ++itL;
-            ++itR;
-        }
-        else if (itL->first < k)
-            ++itL;
-        else
-        {
-            l[k] = a;
-            ++itR;
-        }
-    }
-
-    l.insert(itR, r.end());
-}
-
-void merge(RefinementMap& l, const RefinementMap& r, std::function<TypeId(TypeId, TypeId)> f)
-{
-    if (FFlag::LuauLValueAsKey)
-        return merge(l.NEW_refinements, r.NEW_refinements, f);
-    else
-        return merge(l.DEPRECATED_refinements, r.DEPRECATED_refinements, f);
-}
-
 void addRefinement(RefinementMap& refis, const LValue& lvalue, TypeId ty)
 {
-    if (FFlag::LuauLValueAsKey)
+    refis[lvalue] = ty;
-        refis.NEW_refinements[lvalue] = ty;
-    else
-        refis.DEPRECATED_refinements[toString(lvalue)] = ty;
 }
 
 } // namespace Luau

Analysis/src/Linter.cpp

@@ -12,8 +12,6 @@
 #include <math.h>
 #include <limits.h>
 
-LUAU_FASTFLAGVARIABLE(LuauLintTableCreateTable, false)
-
 namespace Luau
 {
 
@@ -2155,7 +2153,7 @@ private:
                     "table.move uses index 0 but arrays are 1-based; did you mean 1 instead?");
         }
 
-        if (FFlag::LuauLintTableCreateTable && func->index == "create" && node->args.size == 2)
+        if (func->index == "create" && node->args.size == 2)
         {
             // table.create(n, {...})
             if (args[1]->is<AstExprTable>())

Analysis/src/Substitution.cpp

@@ -2,6 +2,7 @@
 #include "Luau/Substitution.h"
 
 #include "Luau/Common.h"
+#include "Luau/TxnLog.h"
 
 #include <algorithm>
 #include <stdexcept>
@@ -13,17 +14,17 @@ namespace Luau
 
 void Tarjan::visitChildren(TypeId ty, int index)
 {
-    ty = follow(ty);
+    ty = log->follow(ty);
 
     if (ignoreChildren(ty))
         return;
 
-    if (const FunctionTypeVar* ftv = get<FunctionTypeVar>(ty))
+    if (const FunctionTypeVar* ftv = log->getMutable<FunctionTypeVar>(ty))
     {
         visitChild(ftv->argTypes);
         visitChild(ftv->retType);
     }
-    else if (const TableTypeVar* ttv = get<TableTypeVar>(ty))
+    else if (const TableTypeVar* ttv = log->getMutable<TableTypeVar>(ty))
     {
         LUAU_ASSERT(!ttv->boundTo);
         for (const auto& [name, prop] : ttv->props)
@@ -40,17 +41,17 @@ void Tarjan::visitChildren(TypeId ty, int index)
         for (TypePackId itp : ttv->instantiatedTypePackParams)
             visitChild(itp);
     }
-    else if (const MetatableTypeVar* mtv = get<MetatableTypeVar>(ty))
+    else if (const MetatableTypeVar* mtv = log->getMutable<MetatableTypeVar>(ty))
     {
         visitChild(mtv->table);
         visitChild(mtv->metatable);
     }
-    else if (const UnionTypeVar* utv = get<UnionTypeVar>(ty))
+    else if (const UnionTypeVar* utv = log->getMutable<UnionTypeVar>(ty))
     {
         for (TypeId opt : utv->options)
             visitChild(opt);
     }
-    else if (const IntersectionTypeVar* itv = get<IntersectionTypeVar>(ty))
+    else if (const IntersectionTypeVar* itv = log->getMutable<IntersectionTypeVar>(ty))
     {
         for (TypeId part : itv->parts)
             visitChild(part);
@@ -59,19 +60,19 @@ void Tarjan::visitChildren(TypeId ty, int index)
 
 void Tarjan::visitChildren(TypePackId tp, int index)
 {
-    tp = follow(tp);
+    tp = log->follow(tp);
 
     if (ignoreChildren(tp))
         return;
 
-    if (const TypePack* tpp = get<TypePack>(tp))
+    if (const TypePack* tpp = log->getMutable<TypePack>(tp))
     {
         for (TypeId tv : tpp->head)
             visitChild(tv);
         if (tpp->tail)
             visitChild(*tpp->tail);
     }
-    else if (const VariadicTypePack* vtp = get<VariadicTypePack>(tp))
+    else if (const VariadicTypePack* vtp = log->getMutable<VariadicTypePack>(tp))
     {
         visitChild(vtp->ty);
     }
@@ -79,7 +80,7 @@ void Tarjan::visitChildren(TypePackId tp, int index)
 
 std::pair<int, bool> Tarjan::indexify(TypeId ty)
 {
-    ty = follow(ty);
+    ty = log->follow(ty);
 
     bool fresh = !typeToIndex.contains(ty);
     int& index = typeToIndex[ty];
@@ -97,7 +98,7 @@ std::pair<int, bool> Tarjan::indexify(TypeId ty)
 
 std::pair<int, bool> Tarjan::indexify(TypePackId tp)
 {
-    tp = follow(tp);
+    tp = log->follow(tp);
 
     bool fresh = !packToIndex.contains(tp);
     int& index = packToIndex[tp];
@@ -115,7 +116,7 @@ std::pair<int, bool> Tarjan::indexify(TypePackId tp)
 
 void Tarjan::visitChild(TypeId ty)
 {
-    ty = follow(ty);
+    ty = log->follow(ty);
 
     edgesTy.push_back(ty);
     edgesTp.push_back(nullptr);
@@ -123,7 +124,7 @@ void Tarjan::visitChild(TypeId ty)
 
 void Tarjan::visitChild(TypePackId tp)
 {
-    tp = follow(tp);
+    tp = log->follow(tp);
 
     edgesTy.push_back(nullptr);
     edgesTp.push_back(tp);
@@ -243,7 +244,7 @@ void Tarjan::clear()
 TarjanResult Tarjan::visitRoot(TypeId ty)
 {
     childCount = 0;
-    ty = follow(ty);
+    ty = log->follow(ty);
 
     clear();
     auto [index, fresh] = indexify(ty);
@@ -254,7 +255,7 @@ TarjanResult Tarjan::visitRoot(TypeId ty)
 TarjanResult Tarjan::visitRoot(TypePackId tp)
 {
     childCount = 0;
-    tp = follow(tp);
+    tp = log->follow(tp);
 
     clear();
     auto [index, fresh] = indexify(tp);
@@ -325,7 +326,7 @@ TarjanResult FindDirty::findDirty(TypePackId tp)
 
 std::optional<TypeId> Substitution::substitute(TypeId ty)
 {
-    ty = follow(ty);
+    ty = log->follow(ty);
     newTypes.clear();
     newPacks.clear();
 
@@ -345,7 +346,7 @@ std::optional<TypeId> Substitution::substitute(TypeId ty)
 
 std::optional<TypePackId> Substitution::substitute(TypePackId tp)
 {
-    tp = follow(tp);
+    tp = log->follow(tp);
     newTypes.clear();
     newPacks.clear();
 
@@ -365,11 +366,11 @@ std::optional<TypePackId> Substitution::substitute(TypePackId tp)
 
 TypeId Substitution::clone(TypeId ty)
 {
-    ty = follow(ty);
+    ty = log->follow(ty);
 
     TypeId result = ty;
 
-    if (const FunctionTypeVar* ftv = get<FunctionTypeVar>(ty))
+    if (const FunctionTypeVar* ftv = log->getMutable<FunctionTypeVar>(ty))
     {
         FunctionTypeVar clone = FunctionTypeVar{ftv->level, ftv->argTypes, ftv->retType, ftv->definition, ftv->hasSelf};
         clone.generics = ftv->generics;
@@ -379,7 +380,7 @@ TypeId Substitution::clone(TypeId ty)
         clone.argNames = ftv->argNames;
         result = addType(std::move(clone));
     }
-    else if (const TableTypeVar* ttv = get<TableTypeVar>(ty))
+    else if (const TableTypeVar* ttv = log->getMutable<TableTypeVar>(ty))
     {
         LUAU_ASSERT(!ttv->boundTo);
         TableTypeVar clone = TableTypeVar{ttv->props, ttv->indexer, ttv->level, ttv->state};
@@ -392,19 +393,19 @@ TypeId Substitution::clone(TypeId ty)
         clone.tags = ttv->tags;
         result = addType(std::move(clone));
     }
-    else if (const MetatableTypeVar* mtv = get<MetatableTypeVar>(ty))
+    else if (const MetatableTypeVar* mtv = log->getMutable<MetatableTypeVar>(ty))
     {
         MetatableTypeVar clone = MetatableTypeVar{mtv->table, mtv->metatable};
         clone.syntheticName = mtv->syntheticName;
         result = addType(std::move(clone));
     }
-    else if (const UnionTypeVar* utv = get<UnionTypeVar>(ty))
+    else if (const UnionTypeVar* utv = log->getMutable<UnionTypeVar>(ty))
     {
         UnionTypeVar clone;
         clone.options = utv->options;
         result = addType(std::move(clone));
     }
-    else if (const IntersectionTypeVar* itv = get<IntersectionTypeVar>(ty))
+    else if (const IntersectionTypeVar* itv = log->getMutable<IntersectionTypeVar>(ty))
     {
         IntersectionTypeVar clone;
         clone.parts = itv->parts;
@@ -417,15 +418,15 @@ TypeId Substitution::clone(TypeId ty)
 
 TypePackId Substitution::clone(TypePackId tp)
 {
-    tp = follow(tp);
+    tp = log->follow(tp);
-    if (const TypePack* tpp = get<TypePack>(tp))
+    if (const TypePack* tpp = log->getMutable<TypePack>(tp))
     {
         TypePack clone;
         clone.head = tpp->head;
         clone.tail = tpp->tail;
         return addTypePack(std::move(clone));
     }
-    else if (const VariadicTypePack* vtp = get<VariadicTypePack>(tp))
+    else if (const VariadicTypePack* vtp = log->getMutable<VariadicTypePack>(tp))
     {
         VariadicTypePack clone;
         clone.ty = vtp->ty;
@@ -437,7 +438,7 @@ TypePackId Substitution::clone(TypePackId tp)
 
 void Substitution::foundDirty(TypeId ty)
 {
-    ty = follow(ty);
+    ty = log->follow(ty);
     if (isDirty(ty))
         newTypes[ty] = clean(ty);
     else
@@ -446,7 +447,7 @@ void Substitution::foundDirty(TypeId ty)
 
 void Substitution::foundDirty(TypePackId tp)
 {
-    tp = follow(tp);
+    tp = log->follow(tp);
     if (isDirty(tp))
         newPacks[tp] = clean(tp);
     else
@@ -455,7 +456,7 @@ void Substitution::foundDirty(TypePackId tp)
 
 TypeId Substitution::replace(TypeId ty)
 {
-    ty = follow(ty);
+    ty = log->follow(ty);
     if (TypeId* prevTy = newTypes.find(ty))
         return *prevTy;
     else
@@ -464,7 +465,7 @@ TypeId Substitution::replace(TypeId ty)
 
 TypePackId Substitution::replace(TypePackId tp)
 {
-    tp = follow(tp);
+    tp = log->follow(tp);
     if (TypePackId* prevTp = newPacks.find(tp))
         return *prevTp;
     else
@@ -473,7 +474,7 @@ TypePackId Substitution::replace(TypePackId tp)
 
 void Substitution::replaceChildren(TypeId ty)
 {
-    ty = follow(ty);
+    ty = log->follow(ty);
 
     if (ignoreChildren(ty))
         return;
@@ -519,7 +520,7 @@ void Substitution::replaceChildren(TypeId ty)
 
 void Substitution::replaceChildren(TypePackId tp)
 {
-    tp = follow(tp);
+    tp = log->follow(tp);
 
     if (ignoreChildren(tp))
         return;

Analysis/src/TxnLog.cpp

@@ -1,6 +1,7 @@
 // This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
 #include "Luau/TxnLog.h"
 
+#include "Luau/ToString.h"
 #include "Luau/TypePack.h"
 
 #include <algorithm>
@@ -80,6 +81,56 @@ void DEPRECATED_TxnLog::popSeen(TypeId lhs, TypeId rhs)
     sharedSeen->pop_back();
 }
 
+const std::string nullPendingResult = "<nullptr>";
+
+std::string toString(PendingType* pending)
+{
+    if (pending == nullptr)
+        return nullPendingResult;
+
+    return toString(pending->pending);
+}
+
+std::string dump(PendingType* pending)
+{
+    if (pending == nullptr)
+    {
+        printf("%s\n", nullPendingResult.c_str());
+        return nullPendingResult;
+    }
+
+    ToStringOptions opts;
+    opts.exhaustive = true;
+    opts.functionTypeArguments = true;
+    std::string result = toString(pending->pending, opts);
+    printf("%s\n", result.c_str());
+    return result;
+}
+
+std::string toString(PendingTypePack* pending)
+{
+    if (pending == nullptr)
+        return nullPendingResult;
+
+    return toString(pending->pending);
+}
+
+std::string dump(PendingTypePack* pending)
+{
+    if (pending == nullptr)
+    {
+        printf("%s\n", nullPendingResult.c_str());
+        return nullPendingResult;
+    }
+
+    ToStringOptions opts;
+    opts.exhaustive = true;
+    opts.functionTypeArguments = true;
+    std::string result = toString(pending->pending, opts);
+    printf("%s\n", result.c_str());
+    return result;
+}
+
 static const TxnLog emptyLog;
 
 const TxnLog* TxnLog::empty()
@@ -199,8 +250,6 @@ PendingTypePack* TxnLog::queue(TypePackId tp)
 
 PendingType* TxnLog::pending(TypeId ty) const
 {
-    LUAU_ASSERT(FFlag::LuauUseCommittingTxnLog);
-
     for (const TxnLog* current = this; current; current = current->parent)
     {
         if (auto it = current->typeVarChanges.find(ty); it != current->typeVarChanges.end())
@@ -212,8 +261,6 @@ PendingType* TxnLog::pending(TypeId ty) const
 
 PendingTypePack* TxnLog::pending(TypePackId tp) const
 {
-    LUAU_ASSERT(FFlag::LuauUseCommittingTxnLog);
-
     for (const TxnLog* current = this; current; current = current->parent)
     {
         if (auto it = current->typePackChanges.find(tp); it != current->typePackChanges.end())
@@ -225,8 +272,6 @@ PendingTypePack* TxnLog::pending(TypePackId tp) const
 
 PendingType* TxnLog::replace(TypeId ty, TypeVar replacement)
 {
-    LUAU_ASSERT(FFlag::LuauUseCommittingTxnLog);
-
     PendingType* newTy = queue(ty);
     newTy->pending = replacement;
     return newTy;
@@ -234,8 +279,6 @@ PendingType* TxnLog::replace(TypeId ty, TypeVar replacement)
 
 PendingTypePack* TxnLog::replace(TypePackId tp, TypePackVar replacement)
 {
-    LUAU_ASSERT(FFlag::LuauUseCommittingTxnLog);
-
     PendingTypePack* newTp = queue(tp);
     newTp->pending = replacement;
     return newTp;
@@ -243,7 +286,6 @@ PendingTypePack* TxnLog::replace(TypePackId tp, TypePackVar replacement)
 
 PendingType* TxnLog::bindTable(TypeId ty, std::optional<TypeId> newBoundTo)
 {
-    LUAU_ASSERT(FFlag::LuauUseCommittingTxnLog);
     LUAU_ASSERT(get<TableTypeVar>(ty));
 
     PendingType* newTy = queue(ty);
@@ -255,7 +297,6 @@ PendingType* TxnLog::bindTable(TypeId ty, std::optional<TypeId> newBoundTo)
 
 PendingType* TxnLog::changeLevel(TypeId ty, TypeLevel newLevel)
 {
-    LUAU_ASSERT(FFlag::LuauUseCommittingTxnLog);
     LUAU_ASSERT(get<FreeTypeVar>(ty) || get<TableTypeVar>(ty) || get<FunctionTypeVar>(ty));
 
     PendingType* newTy = queue(ty);
@@ -278,7 +319,6 @@ PendingType* TxnLog::changeLevel(TypeId ty, TypeLevel newLevel)
 
 PendingTypePack* TxnLog::changeLevel(TypePackId tp, TypeLevel newLevel)
 {
-    LUAU_ASSERT(FFlag::LuauUseCommittingTxnLog);
     LUAU_ASSERT(get<FreeTypePack>(tp));
 
     PendingTypePack* newTp = queue(tp);
@@ -292,7 +332,6 @@ PendingTypePack* TxnLog::changeLevel(TypePackId tp, TypeLevel newLevel)
 
 PendingType* TxnLog::changeIndexer(TypeId ty, std::optional<TableIndexer> indexer)
 {
-    LUAU_ASSERT(FFlag::LuauUseCommittingTxnLog);
     LUAU_ASSERT(get<TableTypeVar>(ty));
 
     PendingType* newTy = queue(ty);
@@ -306,8 +345,6 @@ PendingType* TxnLog::changeIndexer(TypeId ty, std::optional<TableIndexer> indexe
 
 std::optional<TypeLevel> TxnLog::getLevel(TypeId ty) const
 {
-    LUAU_ASSERT(FFlag::LuauUseCommittingTxnLog);
-
     if (FreeTypeVar* ftv = getMutable<FreeTypeVar>(ty))
         return ftv->level;
     else if (TableTypeVar* ttv = getMutable<TableTypeVar>(ty); ttv && (ttv->state == TableState::Free || ttv->state == TableState::Generic))
@@ -318,10 +355,8 @@ std::optional<TypeLevel> TxnLog::getLevel(TypeId ty) const
     return std::nullopt;
 }
 
-TypeId TxnLog::follow(TypeId ty)
+TypeId TxnLog::follow(TypeId ty) const
 {
-    LUAU_ASSERT(FFlag::LuauUseCommittingTxnLog);
-
     return Luau::follow(ty, [this](TypeId ty) {
         PendingType* state = this->pending(ty);
 
@@ -337,8 +372,6 @@ TypeId TxnLog::follow(TypeId ty)
 
 TypePackId TxnLog::follow(TypePackId tp) const
 {
-    LUAU_ASSERT(FFlag::LuauUseCommittingTxnLog);
-
     return Luau::follow(tp, [this](TypePackId tp) {
         PendingTypePack* state = this->pending(tp);
 

Analysis/src/TypeInfer.cpp

@@ -32,6 +32,7 @@ LUAU_FASTFLAGVARIABLE(LuauRecursiveTypeParameterRestriction, false)
 LUAU_FASTFLAGVARIABLE(LuauIfElseBranchTypeUnion, false)
 LUAU_FASTFLAGVARIABLE(LuauIfElseExpectedType2, false)
 LUAU_FASTFLAGVARIABLE(LuauLengthOnCompositeType, false)
+LUAU_FASTFLAGVARIABLE(LuauNoSealedTypeMod, false)
 LUAU_FASTFLAGVARIABLE(LuauQuantifyInPlace2, false)
 LUAU_FASTFLAGVARIABLE(LuauSealExports, false)
 LUAU_FASTFLAGVARIABLE(LuauSingletonTypes, false)
@@ -40,13 +41,12 @@ LUAU_FASTFLAGVARIABLE(LuauTypeAliasDefaults, false)
 LUAU_FASTFLAGVARIABLE(LuauExpectedTypesOfProperties, false)
 LUAU_FASTFLAGVARIABLE(LuauErrorRecoveryType, false)
 LUAU_FASTFLAGVARIABLE(LuauPropertiesGetExpectedType, false)
-LUAU_FASTFLAGVARIABLE(LuauLValueAsKey, false)
-LUAU_FASTFLAGVARIABLE(LuauRefiLookupFromIndexExpr, false)
 LUAU_FASTFLAGVARIABLE(LuauPerModuleUnificationCache, false)
 LUAU_FASTFLAGVARIABLE(LuauProperTypeLevels, false)
 LUAU_FASTFLAGVARIABLE(LuauAscribeCorrectLevelToInferredProperitesOfFreeTables, false)
-LUAU_FASTFLAGVARIABLE(LuauBidirectionalAsExpr, false)
+LUAU_FASTFLAG(LuauUnionTagMatchFix)
 LUAU_FASTFLAGVARIABLE(LuauUnsealedTableLiteral, false)
+LUAU_FASTFLAGVARIABLE(LuauAssertStripsFalsyTypes, false)
 
 namespace Luau
 {
@@ -1117,7 +1117,7 @@ void TypeChecker::check(const ScopePtr& scope, TypeId ty, const ScopePtr& funSco
 
         ty = follow(ty);
 
-        if (tableSelf && !selfTy->persistent)
+        if (tableSelf && (FFlag::LuauNoSealedTypeMod ? tableSelf->state != TableState::Sealed : !selfTy->persistent))
             tableSelf->props[indexName->index.value] = {ty, /* deprecated */ false, {}, indexName->indexLocation};
 
         const FunctionTypeVar* funTy = get<FunctionTypeVar>(ty);
@@ -1130,7 +1130,7 @@ void TypeChecker::check(const ScopePtr& scope, TypeId ty, const ScopePtr& funSco
 
         checkFunctionBody(funScope, ty, *function.func);
 
-        if (tableSelf && !selfTy->persistent)
+        if (tableSelf && (FFlag::LuauNoSealedTypeMod ? tableSelf->state != TableState::Sealed : !selfTy->persistent))
             tableSelf->props[indexName->index.value] = {
                 follow(quantify(funScope, ty, indexName->indexLocation)), /* deprecated */ false, {}, indexName->indexLocation};
     }
@@ -1657,7 +1657,7 @@ std::optional<TypeId> TypeChecker::getIndexTypeFromType(
             RecursionLimiter _rl(&recursionCount, FInt::LuauTypeInferRecursionLimit);
 
             // Not needed when we normalize types.
-            if (FFlag::LuauLValueAsKey && get<AnyTypeVar>(follow(t)))
+            if (get<AnyTypeVar>(follow(t)))
                 return t;
 
             if (std::optional<TypeId> ty = getIndexTypeFromType(scope, t, name, location, false))
@@ -1802,12 +1802,9 @@ ExprResult<TypeId> TypeChecker::checkExpr(const ScopePtr& scope, const AstExprIn
 {
     TypeId ty = checkLValue(scope, expr);
 
-    if (FFlag::LuauRefiLookupFromIndexExpr)
-    {
     if (std::optional<LValue> lvalue = tryGetLValue(expr))
         if (std::optional<TypeId> refiTy = resolveLValue(scope, *lvalue))
             return {*refiTy, {TruthyPredicate{std::move(*lvalue), expr.location}}};
-    }
 
     return {ty};
 }
@@ -2471,33 +2468,28 @@ ExprResult<TypeId> TypeChecker::checkExpr(const ScopePtr& scope, const AstExprBi
 {
     if (expr.op == AstExprBinary::And)
     {
-        ExprResult<TypeId> lhs = checkExpr(scope, *expr.left);
+        auto [lhsTy, lhsPredicates] = checkExpr(scope, *expr.left);
 
-        // We can't just report errors here.
-        // This function can be called from AstStatLocal or from AstStatIf, or even from AstExprBinary (and others).
-        // For now, ignore the errors returned by the predicate resolver.
-        // We may need an extra property for each predicate set that indicates it has been resolved.
-        // Requires a slight modification to the data structure.
         ScopePtr innerScope = childScope(scope, expr.location);
-        resolve(lhs.predicates, innerScope, true);
+        resolve(lhsPredicates, innerScope, true);
 
-        ExprResult<TypeId> rhs = checkExpr(innerScope, *expr.right);
+        auto [rhsTy, rhsPredicates] = checkExpr(innerScope, *expr.right);
 
-        return {checkBinaryOperation(FFlag::LuauDiscriminableUnions ? scope : innerScope, expr, lhs.type, rhs.type),
+        return {checkBinaryOperation(FFlag::LuauDiscriminableUnions ? scope : innerScope, expr, lhsTy, rhsTy),
-            {AndPredicate{std::move(lhs.predicates), std::move(rhs.predicates)}}};
+            {AndPredicate{std::move(lhsPredicates), std::move(rhsPredicates)}}};
     }
     else if (expr.op == AstExprBinary::Or)
     {
-        ExprResult<TypeId> lhs = checkExpr(scope, *expr.left);
+        auto [lhsTy, lhsPredicates] = checkExpr(scope, *expr.left);
 
         ScopePtr innerScope = childScope(scope, expr.location);
-        resolve(lhs.predicates, innerScope, false);
+        resolve(lhsPredicates, innerScope, false);
 
-        ExprResult<TypeId> rhs = checkExpr(innerScope, *expr.right);
+        auto [rhsTy, rhsPredicates] = checkExpr(innerScope, *expr.right);
 
-        // Because of C++, I'm not sure if lhs.predicates was not moved out by the time we call checkBinaryOperation.
+        // Because of C++, I'm not sure if lhsPredicates was not moved out by the time we call checkBinaryOperation.
-        TypeId result = checkBinaryOperation(FFlag::LuauDiscriminableUnions ? scope : innerScope, expr, lhs.type, rhs.type, lhs.predicates);
+        TypeId result = checkBinaryOperation(FFlag::LuauDiscriminableUnions ? scope : innerScope, expr, lhsTy, rhsTy, lhsPredicates);
-        return {result, {OrPredicate{std::move(lhs.predicates), std::move(rhs.predicates)}}};
+        return {result, {OrPredicate{std::move(lhsPredicates), std::move(rhsPredicates)}}};
     }
     else if (expr.op == AstExprBinary::CompareEq || expr.op == AstExprBinary::CompareNe)
     {
@@ -2535,8 +2527,6 @@ ExprResult<TypeId> TypeChecker::checkExpr(const ScopePtr& scope, const AstExprTy
     TypeId annotationType = resolveType(scope, *expr.annotation);
     ExprResult<TypeId> result = checkExpr(scope, *expr.expr, annotationType);
 
-    if (FFlag::LuauBidirectionalAsExpr)
-    {
     // Note: As an optimization, we try 'number <: number | string' first, as that is the more likely case.
     if (canUnify(annotationType, result.type, expr.location).empty())
         return {annotationType, std::move(result.predicates)};
@@ -2547,16 +2537,6 @@ ExprResult<TypeId> TypeChecker::checkExpr(const ScopePtr& scope, const AstExprTy
     reportError(expr.location, TypesAreUnrelated{result.type, annotationType});
     return {errorRecoveryType(annotationType), std::move(result.predicates)};
 }
-    else
-    {
-        ErrorVec errorVec = canUnify(annotationType, result.type, expr.location);
-        reportErrors(errorVec);
-        if (!errorVec.empty())
-            annotationType = errorRecoveryType(annotationType);
-
-        return {annotationType, std::move(result.predicates)};
-    }
-}
 
 ExprResult<TypeId> TypeChecker::checkExpr(const ScopePtr& scope, const AstExprError& expr)
 {
@@ -4295,7 +4275,7 @@ void TypeChecker::unifyWithInstantiationIfNeeded(const ScopePtr& scope, TypeId s
         child.tryUnify(subTy, superTy, /*isFunctionCall*/ false);
         if (!child.errors.empty())
         {
-            TypeId instantiated = instantiate(scope, subTy, state.location);
+            TypeId instantiated = instantiate(scope, subTy, state.location, &child.log);
             if (subTy == instantiated)
             {
                 // Instantiating the argument made no difference, so just report any child errors
@@ -4330,7 +4310,7 @@ void TypeChecker::unifyWithInstantiationIfNeeded(const ScopePtr& scope, TypeId s
 
 bool Instantiation::isDirty(TypeId ty)
 {
-    if (get<FunctionTypeVar>(ty))
+    if (log->getMutable<FunctionTypeVar>(ty))
         return true;
     else
         return false;
@@ -4343,7 +4323,7 @@ bool Instantiation::isDirty(TypePackId tp)
 
 bool Instantiation::ignoreChildren(TypeId ty)
 {
-    if (get<FunctionTypeVar>(ty))
+    if (log->getMutable<FunctionTypeVar>(ty))
         return true;
     else
         return false;
@@ -4351,7 +4331,7 @@ bool Instantiation::ignoreChildren(TypeId ty)
 
 TypeId Instantiation::clean(TypeId ty)
 {
-    const FunctionTypeVar* ftv = get<FunctionTypeVar>(ty);
+    const FunctionTypeVar* ftv = log->getMutable<FunctionTypeVar>(ty);
     LUAU_ASSERT(ftv);
 
     FunctionTypeVar clone = FunctionTypeVar{level, ftv->argTypes, ftv->retType, ftv->definition, ftv->hasSelf};
@@ -4362,6 +4342,7 @@ TypeId Instantiation::clean(TypeId ty)
 
     // Annoyingly, we have to do this even if there are no generics,
     // to replace any generic tables.
+    replaceGenerics.log = log;
     replaceGenerics.level = level;
     replaceGenerics.currentModule = currentModule;
     replaceGenerics.generics.assign(ftv->generics.begin(), ftv->generics.end());
@@ -4383,7 +4364,7 @@ TypePackId Instantiation::clean(TypePackId tp)
 
 bool ReplaceGenerics::ignoreChildren(TypeId ty)
 {
-    if (const FunctionTypeVar* ftv = get<FunctionTypeVar>(ty))
+    if (const FunctionTypeVar* ftv = log->getMutable<FunctionTypeVar>(ty))
         // We aren't recursing in the case of a generic function which
         // binds the same generics. This can happen if, for example, there's recursive types.
         // If T = <a>(a,T)->T then instantiating T should produce T' = (X,T)->T not T' = (X,T')->T'.
@@ -4396,9 +4377,9 @@ bool ReplaceGenerics::ignoreChildren(TypeId ty)
 
 bool ReplaceGenerics::isDirty(TypeId ty)
 {
-    if (const TableTypeVar* ttv = get<TableTypeVar>(ty))
+    if (const TableTypeVar* ttv = log->getMutable<TableTypeVar>(ty))
         return ttv->state == TableState::Generic;
-    else if (get<GenericTypeVar>(ty))
+    else if (log->getMutable<GenericTypeVar>(ty))
         return std::find(generics.begin(), generics.end(), ty) != generics.end();
     else
         return false;
@@ -4406,7 +4387,7 @@ bool ReplaceGenerics::isDirty(TypeId ty)
 
 bool ReplaceGenerics::isDirty(TypePackId tp)
 {
-    if (get<GenericTypePack>(tp))
+    if (log->getMutable<GenericTypePack>(tp))
         return std::find(genericPacks.begin(), genericPacks.end(), tp) != genericPacks.end();
     else
         return false;
@@ -4415,7 +4396,7 @@ bool ReplaceGenerics::isDirty(TypePackId tp)
 TypeId ReplaceGenerics::clean(TypeId ty)
 {
     LUAU_ASSERT(isDirty(ty));
-    if (const TableTypeVar* ttv = get<TableTypeVar>(ty))
+    if (const TableTypeVar* ttv = log->getMutable<TableTypeVar>(ty))
     {
         TableTypeVar clone = TableTypeVar{ttv->props, ttv->indexer, level, TableState::Free};
         clone.methodDefinitionLocations = ttv->methodDefinitionLocations;
@@ -4434,9 +4415,9 @@ TypePackId ReplaceGenerics::clean(TypePackId tp)
 
 bool Quantification::isDirty(TypeId ty)
 {
-    if (const TableTypeVar* ttv = get<TableTypeVar>(ty))
+    if (const TableTypeVar* ttv = log->getMutable<TableTypeVar>(ty))
         return level.subsumes(ttv->level) && ((ttv->state == TableState::Free) || (ttv->state == TableState::Unsealed));
-    else if (const FreeTypeVar* ftv = get<FreeTypeVar>(ty))
+    else if (const FreeTypeVar* ftv = log->getMutable<FreeTypeVar>(ty))
         return level.subsumes(ftv->level);
     else
         return false;
@@ -4444,7 +4425,7 @@ bool Quantification::isDirty(TypeId ty)
 
 bool Quantification::isDirty(TypePackId tp)
 {
-    if (const FreeTypePack* ftv = get<FreeTypePack>(tp))
+    if (const FreeTypePack* ftv = log->getMutable<FreeTypePack>(tp))
         return level.subsumes(ftv->level);
     else
         return false;
@@ -4453,7 +4434,7 @@ bool Quantification::isDirty(TypePackId tp)
 TypeId Quantification::clean(TypeId ty)
 {
     LUAU_ASSERT(isDirty(ty));
-    if (const TableTypeVar* ttv = get<TableTypeVar>(ty))
+    if (const TableTypeVar* ttv = log->getMutable<TableTypeVar>(ty))
     {
         TableState state = (ttv->state == TableState::Unsealed ? TableState::Sealed : TableState::Generic);
         TableTypeVar clone = TableTypeVar{ttv->props, ttv->indexer, level, state};
@@ -4479,9 +4460,9 @@ TypePackId Quantification::clean(TypePackId tp)
 
 bool Anyification::isDirty(TypeId ty)
 {
-    if (const TableTypeVar* ttv = get<TableTypeVar>(ty))
+    if (const TableTypeVar* ttv = log->getMutable<TableTypeVar>(ty))
         return (ttv->state == TableState::Free || (FFlag::LuauSealExports && ttv->state == TableState::Unsealed));
-    else if (get<FreeTypeVar>(ty))
+    else if (log->getMutable<FreeTypeVar>(ty))
         return true;
     else
         return false;
@@ -4489,7 +4470,7 @@ bool Anyification::isDirty(TypeId ty)
 
 bool Anyification::isDirty(TypePackId tp)
 {
-    if (get<FreeTypePack>(tp))
+    if (log->getMutable<FreeTypePack>(tp))
         return true;
     else
         return false;
@@ -4498,7 +4479,7 @@ bool Anyification::isDirty(TypePackId tp)
 TypeId Anyification::clean(TypeId ty)
 {
     LUAU_ASSERT(isDirty(ty));
-    if (const TableTypeVar* ttv = get<TableTypeVar>(ty))
+    if (const TableTypeVar* ttv = log->getMutable<TableTypeVar>(ty))
     {
         TableTypeVar clone = TableTypeVar{ttv->props, ttv->indexer, ttv->level, TableState::Sealed};
         clone.methodDefinitionLocations = ttv->methodDefinitionLocations;
@@ -4535,6 +4516,7 @@ TypeId TypeChecker::quantify(const ScopePtr& scope, TypeId ty, Location location
         return ty;
     }
 
+    quantification.log = TxnLog::empty();
     quantification.level = scope->level;
     quantification.generics.clear();
     quantification.genericPacks.clear();
@@ -4558,8 +4540,11 @@ TypeId TypeChecker::quantify(const ScopePtr& scope, TypeId ty, Location location
     return *qty;
 }
 
-TypeId TypeChecker::instantiate(const ScopePtr& scope, TypeId ty, Location location)
+TypeId TypeChecker::instantiate(const ScopePtr& scope, TypeId ty, Location location, const TxnLog* log)
 {
+    LUAU_ASSERT(log != nullptr);
+
+    instantiation.log = FFlag::LuauUseCommittingTxnLog ? log : TxnLog::empty();
     instantiation.level = scope->level;
     instantiation.currentModule = currentModule;
     std::optional<TypeId> instantiated = instantiation.substitute(ty);
@@ -4574,6 +4559,7 @@ TypeId TypeChecker::instantiate(const ScopePtr& scope, TypeId ty, Location locat
 
 TypeId TypeChecker::anyify(const ScopePtr& scope, TypeId ty, Location location)
 {
+    anyification.log = TxnLog::empty();
     anyification.anyType = anyType;
     anyification.anyTypePack = anyTypePack;
     anyification.currentModule = currentModule;
@@ -4589,6 +4575,7 @@ TypeId TypeChecker::anyify(const ScopePtr& scope, TypeId ty, Location location)
 
 TypePackId TypeChecker::anyify(const ScopePtr& scope, TypePackId ty, Location location)
 {
+    anyification.log = TxnLog::empty();
     anyification.anyType = anyType;
     anyification.anyTypePack = anyTypePack;
     anyification.currentModule = currentModule;
@@ -4660,7 +4647,7 @@ void TypeChecker::diagnoseMissingTableKey(UnknownProperty* utk, TypeErrorData& d
         }
     };
 
-    if (auto ttv = getTableType(follow(utk->table)))
+    if (auto ttv = getTableType(FFlag::LuauUnionTagMatchFix ? utk->table : follow(utk->table)))
         accumulate(ttv->props);
     else if (auto ctv = get<ClassTypeVar>(follow(utk->table)))
     {
@@ -4775,6 +4762,29 @@ TypePackId TypeChecker::errorRecoveryTypePack(TypePackId guess)
     return getSingletonTypes().errorRecoveryTypePack(guess);
 }
 
+TypeIdPredicate TypeChecker::mkTruthyPredicate(bool sense) {
+    return [this, sense](TypeId ty) -> std::optional<TypeId> {
+        // any/error/free gets a special pass unconditionally because they can't be decided.
+        if (get<AnyTypeVar>(ty) || get<ErrorTypeVar>(ty) || get<FreeTypeVar>(ty))
+            return ty;
+
+        // maps boolean primitive to the corresponding singleton equal to sense
+        if (isPrim(ty, PrimitiveTypeVar::Boolean))
+            return singletonType(sense);
+
+        // if we have boolean singleton, eliminate it if the sense doesn't match with that singleton
+        if (auto boolean = get<BooleanSingleton>(get<SingletonTypeVar>(ty)))
+            return boolean->value == sense ? std::optional<TypeId>(ty) : std::nullopt;
+
+        // if we have nil, eliminate it if sense is true, otherwise take it
+        if (isNil(ty))
+            return sense ? std::nullopt : std::optional<TypeId>(ty);
+
+        // at this point, anything else is kept if sense is true, or eliminated otherwise
+        return sense ? std::optional<TypeId>(ty) : std::nullopt;
+    };
+}
+
 std::optional<TypeId> TypeChecker::filterMap(TypeId type, TypeIdPredicate predicate)
 {
     std::vector<TypeId> types = Luau::filterMap(type, predicate);
@@ -4783,6 +4793,11 @@ std::optional<TypeId> TypeChecker::filterMap(TypeId type, TypeIdPredicate predic
     return std::nullopt;
 }
 
+std::optional<TypeId> TypeChecker::pickTypesFromSense(TypeId type, bool sense)
+{
+    return filterMap(type, mkTruthyPredicate(sense));
+}
+
 TypeId TypeChecker::addTV(TypeVar&& tv)
 {
     return currentModule->internalTypes.addType(std::move(tv));
@@ -4962,6 +4977,7 @@ TypeId TypeChecker::resolveType(const ScopePtr& scope, const AstType& annotation
             if (notEnoughParameters && hasDefaultParameters)
             {
                 // 'applyTypeFunction' is used to substitute default types that reference previous generic types
+                applyTypeFunction.log = TxnLog::empty();
                 applyTypeFunction.typeArguments.clear();
                 applyTypeFunction.typePackArguments.clear();
                 applyTypeFunction.currentModule = currentModule;
@@ -5293,6 +5309,7 @@ TypeId TypeChecker::instantiateTypeFun(const ScopePtr& scope, const TypeFun& tf,
     for (size_t i = 0; i < tf.typePackParams.size(); ++i)
         applyTypeFunction.typePackArguments[tf.typePackParams[i].tp] = typePackParams[i];
 
+    applyTypeFunction.log = TxnLog::empty();
     applyTypeFunction.currentModule = currentModule;
     applyTypeFunction.level = scope->level;
     applyTypeFunction.encounteredForwardedType = false;
@@ -5507,9 +5524,6 @@ void TypeChecker::refineLValue(const LValue& lvalue, RefinementMap& refis, const
 
 std::optional<TypeId> TypeChecker::resolveLValue(const ScopePtr& scope, const LValue& lvalue)
 {
-    if (!FFlag::LuauLValueAsKey)
-        return DEPRECATED_resolveLValue(scope, lvalue);
-
     // We want to be walking the Scope parents.
     // We'll also want to walk up the LValue path. As we do this, we need to save each LValue because we must walk back.
     // For example:
@@ -5529,7 +5543,7 @@ std::optional<TypeId> TypeChecker::resolveLValue(const ScopePtr& scope, const LV
         const LValue* currentLValue = &lvalue;
         while (currentLValue)
         {
-            if (auto it = currentScope->refinements.NEW_refinements.find(*currentLValue); it != currentScope->refinements.NEW_refinements.end())
+            if (auto it = currentScope->refinements.find(*currentLValue); it != currentScope->refinements.end())
             {
                 found = it->second;
                 break;
@@ -5576,43 +5590,9 @@ std::optional<TypeId> TypeChecker::resolveLValue(const ScopePtr& scope, const LV
     return std::nullopt;
 }
 
-std::optional<TypeId> TypeChecker::DEPRECATED_resolveLValue(const ScopePtr& scope, const LValue& lvalue)
-{
-    auto [symbol, keys] = getFullName(lvalue);
-
-    ScopePtr currentScope = scope;
-    while (currentScope)
-    {
-        if (auto it = currentScope->refinements.DEPRECATED_refinements.find(toString(lvalue)); it != currentScope->refinements.DEPRECATED_refinements.end())
-            return it->second;
-
-        // Should not be using scope->lookup. This is already recursive.
-        if (auto it = currentScope->bindings.find(symbol); it != currentScope->bindings.end())
-        {
-            std::optional<TypeId> currentTy = it->second.typeId;
-
-            for (std::string key : keys)
-            {
-                // TODO: This function probably doesn't need Location at all, or at least should hide the argument.
-                currentTy = getIndexTypeFromType(scope, *currentTy, key, Location(), false);
-                if (!currentTy)
-                    break;
-            }
-
-            return currentTy;
-        }
-
-        currentScope = currentScope->parent;
-    }
-
-    return std::nullopt;
-}
-
 std::optional<TypeId> TypeChecker::resolveLValue(const RefinementMap& refis, const ScopePtr& scope, const LValue& lvalue)
 {
-    if (auto it = refis.DEPRECATED_refinements.find(toString(lvalue)); it != refis.DEPRECATED_refinements.end())
+    if (auto it = refis.find(lvalue); it != refis.end())
-        return it->second;
-    else if (auto it = refis.NEW_refinements.find(lvalue); it != refis.NEW_refinements.end())
         return it->second;
     else
         return resolveLValue(scope, lvalue);
@@ -5660,6 +5640,16 @@ void TypeChecker::resolve(const Predicate& predicate, ErrorVec& errVec, Refineme
 }
 
 void TypeChecker::resolve(const TruthyPredicate& truthyP, ErrorVec& errVec, RefinementMap& refis, const ScopePtr& scope, bool sense, bool fromOr)
+{
+    if (FFlag::LuauAssertStripsFalsyTypes)
+    {
+        std::optional<TypeId> ty = resolveLValue(refis, scope, truthyP.lvalue);
+        if (ty && fromOr)
+            return addRefinement(refis, truthyP.lvalue, *ty);
+
+        refineLValue(truthyP.lvalue, refis, scope, mkTruthyPredicate(sense));
+    }
+    else
     {
         auto predicate = [sense](TypeId option) -> std::optional<TypeId> {
             if (isUndecidable(option) || isBoolean(option) || isNil(option) != sense)
@@ -5692,6 +5682,7 @@ void TypeChecker::resolve(const TruthyPredicate& truthyP, ErrorVec& errVec, Refi
                 addRefinement(refis, truthyP.lvalue, *result);
         }
     }
+}
 
 void TypeChecker::resolve(const AndPredicate& andP, ErrorVec& errVec, RefinementMap& refis, const ScopePtr& scope, bool sense)
 {

Analysis/src/TypeVar.cpp

@@ -27,6 +27,7 @@ LUAU_FASTFLAG(LuauLengthOnCompositeType)
 LUAU_FASTFLAGVARIABLE(LuauMetatableAreEqualRecursion, false)
 LUAU_FASTFLAGVARIABLE(LuauRefactorTypeVarQuestions, false)
 LUAU_FASTFLAG(LuauErrorRecoveryType)
+LUAU_FASTFLAG(LuauUnionTagMatchFix)
 
 namespace Luau
 {
@@ -288,10 +289,13 @@ std::optional<TypeId> getMetatable(TypeId type)
 
 const TableTypeVar* getTableType(TypeId type)
 {
+    if (FFlag::LuauUnionTagMatchFix)
+        type = follow(type);
+
     if (const TableTypeVar* ttv = get<TableTypeVar>(type))
         return ttv;
     else if (const MetatableTypeVar* mtv = get<MetatableTypeVar>(type))
-        return get<TableTypeVar>(mtv->table);
+        return get<TableTypeVar>(FFlag::LuauUnionTagMatchFix ? follow(mtv->table) : mtv->table);
     else
         return nullptr;
 }
@@ -308,7 +312,7 @@ const std::string* getName(TypeId type)
     {
         if (mtv->syntheticName)
             return &*mtv->syntheticName;
-        type = mtv->table;
+        type = FFlag::LuauUnionTagMatchFix ? follow(mtv->table) : mtv->table;
     }
 
     if (auto ttv = get<TableTypeVar>(type))

Analysis/src/TypedAllocator.cpp

@@ -20,7 +20,6 @@ const size_t kPageSize = sysconf(_SC_PAGESIZE);
 #include <stdlib.h>
 
 LUAU_FASTFLAG(DebugLuauFreezeArena)
-LUAU_FASTFLAGVARIABLE(LuauTypedAllocatorZeroStart, false)
 
 namespace Luau
 {

Analysis/src/Unifier.cpp

@@ -8,6 +8,7 @@
 #include "Luau/TypeUtils.h"
 #include "Luau/TimeTrace.h"
 #include "Luau/VisitTypeVar.h"
+#include "Luau/ToString.h"
 
 #include <algorithm>
 
@@ -22,6 +23,7 @@ LUAU_FASTFLAG(LuauSingletonTypes)
 LUAU_FASTFLAG(LuauErrorRecoveryType);
 LUAU_FASTFLAG(LuauProperTypeLevels);
 LUAU_FASTFLAGVARIABLE(LuauUnifyPackTails, false)
+LUAU_FASTFLAGVARIABLE(LuauUnionTagMatchFix, false)
 
 namespace Luau
 {
@@ -224,6 +226,19 @@ static std::optional<TypeError> hasUnificationTooComplex(const ErrorVec& errors)
 
 // Used for tagged union matching heuristic, returns first singleton type field
 static std::optional<std::pair<Luau::Name, const SingletonTypeVar*>> getTableMatchTag(TypeId type)
+{
+    if (FFlag::LuauUnionTagMatchFix)
+    {
+        if (auto ttv = getTableType(type))
+        {
+            for (auto&& [name, prop] : ttv->props)
+            {
+                if (auto sing = get<SingletonTypeVar>(follow(prop.type)))
+                    return {{name, sing}};
+            }
+        }
+    }
+    else
     {
         type = follow(type);
 
@@ -239,6 +254,7 @@ static std::optional<std::pair<Luau::Name, const SingletonTypeVar*>> getTableMat
         {
             return getTableMatchTag(mttv->table);
         }
+    }
 
     return std::nullopt;
 }
@@ -507,6 +523,73 @@ void Unifier::tryUnify_(TypeId subTy, TypeId superTy, bool isFunctionCall, bool
     }
 
     if (const UnionTypeVar* uv = FFlag::LuauUseCommittingTxnLog ? log.getMutable<UnionTypeVar>(subTy) : get<UnionTypeVar>(subTy))
+    {
+        tryUnifyUnionWithType(subTy, uv, superTy);
+    }
+    else if (const UnionTypeVar* uv = FFlag::LuauUseCommittingTxnLog ? log.getMutable<UnionTypeVar>(superTy) : get<UnionTypeVar>(superTy))
+    {
+        tryUnifyTypeWithUnion(subTy, superTy, uv, cacheEnabled, isFunctionCall);
+    }
+    else if (const IntersectionTypeVar* uv =
+                 FFlag::LuauUseCommittingTxnLog ? log.getMutable<IntersectionTypeVar>(superTy) : get<IntersectionTypeVar>(superTy))
+    {
+        tryUnifyTypeWithIntersection(subTy, superTy, uv);
+    }
+    else if (const IntersectionTypeVar* uv =
+                 FFlag::LuauUseCommittingTxnLog ? log.getMutable<IntersectionTypeVar>(subTy) : get<IntersectionTypeVar>(subTy))
+    {
+        tryUnifyIntersectionWithType(subTy, uv, superTy, cacheEnabled, isFunctionCall);
+    }
+    else if ((FFlag::LuauUseCommittingTxnLog && log.getMutable<PrimitiveTypeVar>(superTy) && log.getMutable<PrimitiveTypeVar>(subTy)) ||
+             (!FFlag::LuauUseCommittingTxnLog && get<PrimitiveTypeVar>(superTy) && get<PrimitiveTypeVar>(subTy)))
+        tryUnifyPrimitives(subTy, superTy);
+
+    else if (FFlag::LuauSingletonTypes &&
+             ((FFlag::LuauUseCommittingTxnLog ? log.getMutable<PrimitiveTypeVar>(superTy) : get<PrimitiveTypeVar>(superTy)) ||
+                 (FFlag::LuauUseCommittingTxnLog ? log.getMutable<SingletonTypeVar>(superTy) : get<SingletonTypeVar>(superTy))) &&
+             (FFlag::LuauUseCommittingTxnLog ? log.getMutable<SingletonTypeVar>(subTy) : get<SingletonTypeVar>(subTy)))
+        tryUnifySingletons(subTy, superTy);
+
+    else if ((FFlag::LuauUseCommittingTxnLog && log.getMutable<FunctionTypeVar>(superTy) && log.getMutable<FunctionTypeVar>(subTy)) ||
+             (!FFlag::LuauUseCommittingTxnLog && get<FunctionTypeVar>(superTy) && get<FunctionTypeVar>(subTy)))
+        tryUnifyFunctions(subTy, superTy, isFunctionCall);
+
+    else if ((FFlag::LuauUseCommittingTxnLog && log.getMutable<TableTypeVar>(superTy) && log.getMutable<TableTypeVar>(subTy)) ||
+             (!FFlag::LuauUseCommittingTxnLog && get<TableTypeVar>(superTy) && get<TableTypeVar>(subTy)))
+    {
+        tryUnifyTables(subTy, superTy, isIntersection);
+
+        if (cacheEnabled && errors.empty())
+            cacheResult(subTy, superTy);
+    }
+
+    // tryUnifyWithMetatable assumes its first argument is a MetatableTypeVar. The check is otherwise symmetrical.
+    else if ((FFlag::LuauUseCommittingTxnLog && log.getMutable<MetatableTypeVar>(superTy)) ||
+             (!FFlag::LuauUseCommittingTxnLog && get<MetatableTypeVar>(superTy)))
+        tryUnifyWithMetatable(subTy, superTy, /*reversed*/ false);
+    else if ((FFlag::LuauUseCommittingTxnLog && log.getMutable<MetatableTypeVar>(subTy)) ||
+             (!FFlag::LuauUseCommittingTxnLog && get<MetatableTypeVar>(subTy)))
+        tryUnifyWithMetatable(superTy, subTy, /*reversed*/ true);
+
+    else if ((FFlag::LuauUseCommittingTxnLog && log.getMutable<ClassTypeVar>(superTy)) ||
+             (!FFlag::LuauUseCommittingTxnLog && get<ClassTypeVar>(superTy)))
+        tryUnifyWithClass(subTy, superTy, /*reversed*/ false);
+
+    // Unification of nonclasses with classes is almost, but not quite symmetrical.
+    // The order in which we perform this test is significant in the case that both types are classes.
+    else if ((FFlag::LuauUseCommittingTxnLog && log.getMutable<ClassTypeVar>(subTy)) || (!FFlag::LuauUseCommittingTxnLog && get<ClassTypeVar>(subTy)))
+        tryUnifyWithClass(subTy, superTy, /*reversed*/ true);
+
+    else
+        reportError(TypeError{location, TypeMismatch{superTy, subTy}});
+
+    if (FFlag::LuauUseCommittingTxnLog)
+        log.popSeen(superTy, subTy);
+    else
+        DEPRECATED_log.popSeen(superTy, subTy);
+}
+
+void Unifier::tryUnifyUnionWithType(TypeId subTy, const UnionTypeVar* uv, TypeId superTy)
 {
     // A | B <: T if A <: T and B <: T
     bool failed = false;
@@ -564,7 +647,8 @@ void Unifier::tryUnify_(TypeId subTy, TypeId superTy, bool isFunctionCall, bool
             reportError(TypeError{location, TypeMismatch{superTy, subTy}});
     }
 }
-    else if (const UnionTypeVar* uv = FFlag::LuauUseCommittingTxnLog ? log.getMutable<UnionTypeVar>(superTy) : get<UnionTypeVar>(superTy))
+
+void Unifier::tryUnifyTypeWithUnion(TypeId subTy, TypeId superTy, const UnionTypeVar* uv, bool cacheEnabled, bool isFunctionCall)
 {
     // T <: A | B if T <: A or T <: B
     bool found = false;
@@ -606,6 +690,8 @@ void Unifier::tryUnify_(TypeId subTy, TypeId superTy, bool isFunctionCall, bool
 
     if (!foundHeuristic && cacheEnabled)
     {
+        auto& cache = sharedState.cachedUnify;
+
         for (size_t i = 0; i < uv->options.size(); ++i)
         {
             TypeId type = uv->options[i];
@@ -657,14 +743,13 @@ void Unifier::tryUnify_(TypeId subTy, TypeId superTy, bool isFunctionCall, bool
     else if (!found)
     {
         if ((failedOptionCount == 1 || foundHeuristic) && failedOption)
-                reportError(
+            reportError(TypeError{location, TypeMismatch{superTy, subTy, "None of the union options are compatible. For example:", *failedOption}});
-                    TypeError{location, TypeMismatch{superTy, subTy, "None of the union options are compatible. For example:", *failedOption}});
         else
             reportError(TypeError{location, TypeMismatch{superTy, subTy, "none of the union options are compatible"}});
     }
 }
-    else if (const IntersectionTypeVar* uv =
+
-                 FFlag::LuauUseCommittingTxnLog ? log.getMutable<IntersectionTypeVar>(superTy) : get<IntersectionTypeVar>(superTy))
+void Unifier::tryUnifyTypeWithIntersection(TypeId subTy, TypeId superTy, const IntersectionTypeVar* uv)
 {
     std::optional<TypeError> unificationTooComplex;
     std::optional<TypeError> firstFailedOption;
@@ -694,8 +779,8 @@ void Unifier::tryUnify_(TypeId subTy, TypeId superTy, bool isFunctionCall, bool
     else if (firstFailedOption)
         reportError(TypeError{location, TypeMismatch{superTy, subTy, "Not all intersection parts are compatible.", *firstFailedOption}});
 }
-    else if (const IntersectionTypeVar* uv =
+
-                 FFlag::LuauUseCommittingTxnLog ? log.getMutable<IntersectionTypeVar>(subTy) : get<IntersectionTypeVar>(subTy))
+void Unifier::tryUnifyIntersectionWithType(TypeId subTy, const IntersectionTypeVar* uv, TypeId superTy, bool cacheEnabled, bool isFunctionCall)
 {
     // A & B <: T if T <: A or T <: B
     bool found = false;
@@ -705,6 +790,8 @@ void Unifier::tryUnify_(TypeId subTy, TypeId superTy, bool isFunctionCall, bool
 
     if (cacheEnabled)
     {
+        auto& cache = sharedState.cachedUnify;
+
         for (size_t i = 0; i < uv->parts.size(); ++i)
         {
             TypeId type = uv->parts[i];
@@ -748,54 +835,6 @@ void Unifier::tryUnify_(TypeId subTy, TypeId superTy, bool isFunctionCall, bool
         reportError(TypeError{location, TypeMismatch{superTy, subTy, "none of the intersection parts are compatible"}});
     }
 }
-    else if ((FFlag::LuauUseCommittingTxnLog && log.getMutable<PrimitiveTypeVar>(superTy) && log.getMutable<PrimitiveTypeVar>(subTy)) ||
-             (!FFlag::LuauUseCommittingTxnLog && get<PrimitiveTypeVar>(superTy) && get<PrimitiveTypeVar>(subTy)))
-        tryUnifyPrimitives(subTy, superTy);
-
-    else if (FFlag::LuauSingletonTypes &&
-             ((FFlag::LuauUseCommittingTxnLog ? log.getMutable<PrimitiveTypeVar>(superTy) : get<PrimitiveTypeVar>(superTy)) ||
-                 (FFlag::LuauUseCommittingTxnLog ? log.getMutable<SingletonTypeVar>(superTy) : get<SingletonTypeVar>(superTy))) &&
-             (FFlag::LuauUseCommittingTxnLog ? log.getMutable<SingletonTypeVar>(subTy) : get<SingletonTypeVar>(subTy)))
-        tryUnifySingletons(subTy, superTy);
-
-    else if ((FFlag::LuauUseCommittingTxnLog && log.getMutable<FunctionTypeVar>(superTy) && log.getMutable<FunctionTypeVar>(subTy)) ||
-             (!FFlag::LuauUseCommittingTxnLog && get<FunctionTypeVar>(superTy) && get<FunctionTypeVar>(subTy)))
-        tryUnifyFunctions(subTy, superTy, isFunctionCall);
-
-    else if ((FFlag::LuauUseCommittingTxnLog && log.getMutable<TableTypeVar>(superTy) && log.getMutable<TableTypeVar>(subTy)) ||
-             (!FFlag::LuauUseCommittingTxnLog && get<TableTypeVar>(superTy) && get<TableTypeVar>(subTy)))
-    {
-        tryUnifyTables(subTy, superTy, isIntersection);
-
-        if (cacheEnabled && errors.empty())
-            cacheResult(subTy, superTy);
-    }
-
-    // tryUnifyWithMetatable assumes its first argument is a MetatableTypeVar. The check is otherwise symmetrical.
-    else if ((FFlag::LuauUseCommittingTxnLog && log.getMutable<MetatableTypeVar>(superTy)) ||
-             (!FFlag::LuauUseCommittingTxnLog && get<MetatableTypeVar>(superTy)))
-        tryUnifyWithMetatable(subTy, superTy, /*reversed*/ false);
-    else if ((FFlag::LuauUseCommittingTxnLog && log.getMutable<MetatableTypeVar>(subTy)) ||
-             (!FFlag::LuauUseCommittingTxnLog && get<MetatableTypeVar>(subTy)))
-        tryUnifyWithMetatable(superTy, subTy, /*reversed*/ true);
-
-    else if ((FFlag::LuauUseCommittingTxnLog && log.getMutable<ClassTypeVar>(superTy)) ||
-             (!FFlag::LuauUseCommittingTxnLog && get<ClassTypeVar>(superTy)))
-        tryUnifyWithClass(subTy, superTy, /*reversed*/ false);
-
-    // Unification of nonclasses with classes is almost, but not quite symmetrical.
-    // The order in which we perform this test is significant in the case that both types are classes.
-    else if ((FFlag::LuauUseCommittingTxnLog && log.getMutable<ClassTypeVar>(subTy)) || (!FFlag::LuauUseCommittingTxnLog && get<ClassTypeVar>(subTy)))
-        tryUnifyWithClass(subTy, superTy, /*reversed*/ true);
-
-    else
-        reportError(TypeError{location, TypeMismatch{superTy, subTy}});
-
-    if (FFlag::LuauUseCommittingTxnLog)
-        log.popSeen(superTy, subTy);
-    else
-        DEPRECATED_log.popSeen(superTy, subTy);
-}
 
 void Unifier::cacheResult(TypeId subTy, TypeId superTy)
 {
@@ -1119,8 +1158,8 @@ void Unifier::tryUnify_(TypePackId subTp, TypePackId superTp, bool isFunctionCal
             auto [superTypes, superTail] = logAwareFlatten(superTp, log);
             auto [subTypes, subTail] = logAwareFlatten(subTp, log);
 
-            bool noInfiniteGrowth =
+            bool noInfiniteGrowth = (superTypes.size() != subTypes.size()) && (superTail && log.getMutable<FreeTypePack>(*superTail)) &&
-                (superTypes.size() != subTypes.size()) && (superTail && get<FreeTypePack>(*superTail)) && (subTail && get<FreeTypePack>(*subTail));
+                                    (subTail && log.getMutable<FreeTypePack>(*subTail));
 
             auto superIter = WeirdIter(superTp, log);
             auto subIter = WeirdIter(subTp, log);
@@ -1667,6 +1706,13 @@ void Unifier::tryUnifyTables(TypeId subTy, TypeId superTy, bool isIntersection)
 
     TableTypeVar* superTable = getMutable<TableTypeVar>(superTy);
     TableTypeVar* subTable = getMutable<TableTypeVar>(subTy);
+
+    if (FFlag::LuauUseCommittingTxnLog)
+    {
+        superTable = log.getMutable<TableTypeVar>(superTy);
+        subTable = log.getMutable<TableTypeVar>(subTy);
+    }
+
     if (!superTable || !subTable)
         ice("passed non-table types to unifyTables");
 
@@ -1679,7 +1725,11 @@ void Unifier::tryUnifyTables(TypeId subTy, TypeId superTy, bool isIntersection)
         for (const auto& [propName, superProp] : superTable->props)
         {
             auto subIter = subTable->props.find(propName);
-            if (subIter == subTable->props.end() && !isOptional(superProp.type) && !get<AnyTypeVar>(follow(superProp.type)))
+
+            bool isAny =
+                FFlag::LuauUseCommittingTxnLog ? log.getMutable<AnyTypeVar>(log.follow(superProp.type)) : get<AnyTypeVar>(follow(superProp.type));
+
+            if (subIter == subTable->props.end() && !isOptional(superProp.type) && !isAny)
                 missingProperties.push_back(propName);
         }
 
@@ -1697,7 +1747,10 @@ void Unifier::tryUnifyTables(TypeId subTy, TypeId superTy, bool isIntersection)
         for (const auto& [propName, subProp] : subTable->props)
         {
             auto superIter = superTable->props.find(propName);
-            if (superIter == superTable->props.end() && !isOptional(subProp.type) && !get<AnyTypeVar>(follow(subProp.type)))
+
+            bool isAny =
+                FFlag::LuauUseCommittingTxnLog ? log.getMutable<AnyTypeVar>(log.follow(subProp.type)) : get<AnyTypeVar>(follow(subProp.type));
+            if (superIter == superTable->props.end() && !isOptional(subProp.type) && !isAny)
                 extraProperties.push_back(propName);
         }
 
@@ -1775,6 +1828,7 @@ void Unifier::tryUnifyTables(TypeId subTy, TypeId superTy, bool isIntersection)
                 TableTypeVar* ttv = getMutable<TableTypeVar>(pendingSub);
                 LUAU_ASSERT(ttv);
                 ttv->props[name] = prop;
+                subTable = ttv;
             }
             else
             {
@@ -1831,6 +1885,7 @@ void Unifier::tryUnifyTables(TypeId subTy, TypeId superTy, bool isIntersection)
                 PendingType* pendingSuper = log.queue(superTy);
                 TableTypeVar* pendingSuperTtv = getMutable<TableTypeVar>(pendingSuper);
                 pendingSuperTtv->props[name] = clone;
+                superTable = pendingSuperTtv;
             }
             else
             {
@@ -1853,6 +1908,7 @@ void Unifier::tryUnifyTables(TypeId subTy, TypeId superTy, bool isIntersection)
                 PendingType* pendingSuper = log.queue(superTy);
                 TableTypeVar* pendingSuperTtv = getMutable<TableTypeVar>(pendingSuper);
                 pendingSuperTtv->props[name] = prop;
+                superTable = pendingSuperTtv;
             }
             else
             {
@@ -1967,7 +2023,7 @@ void Unifier::tryUnifyTables(TypeId subTy, TypeId superTy, bool isIntersection)
         }
         else
         {
-            DEPRECATED_log(subTy);
+            DEPRECATED_log(subTable);
             subTable->boundTo = superTy;
         }
     }
@@ -2408,8 +2464,7 @@ void Unifier::tryUnifyWithMetatable(TypeId subTy, TypeId superTy, bool reversed)
         if (auto e = hasUnificationTooComplex(innerState.errors))
             reportError(*e);
         else if (!innerState.errors.empty())
-            reportError(
+            reportError(TypeError{location, TypeMismatch{reversed ? subTy : superTy, reversed ? superTy : subTy, "", innerState.errors.front()}});
-                TypeError{location, TypeMismatch{reversed ? subTy : superTy, reversed ? superTy : subTy, "", innerState.errors.front()}});
 
         if (FFlag::LuauUseCommittingTxnLog)
             log.concat(std::move(innerState.log));

Ast/src/Parser.cpp

@@ -10,7 +10,6 @@
 // See docs/SyntaxChanges.md for an explanation.
 LUAU_FASTINTVARIABLE(LuauRecursionLimit, 1000)
 LUAU_FASTINTVARIABLE(LuauParseErrorLimit, 100)
-LUAU_FASTFLAGVARIABLE(LuauFixAmbiguousErrorRecoveryInAssign, false)
 LUAU_FASTFLAGVARIABLE(LuauParseSingletonTypes, false)
 LUAU_FASTFLAGVARIABLE(LuauParseTypeAliasDefaults, false)
 LUAU_FASTFLAGVARIABLE(LuauParseRecoverTypePackEllipsis, false)
@@ -957,7 +956,7 @@ AstStat* Parser::parseAssignment(AstExpr* initial)
     {
         nextLexeme();
 
-        AstExpr* expr = parsePrimaryExpr(/* asStatement= */ FFlag::LuauFixAmbiguousErrorRecoveryInAssign);
+        AstExpr* expr = parsePrimaryExpr(/* asStatement= */ true);
 
         if (!isExprLValue(expr))
             expr = reportExprError(expr->location, copy({expr}), "Assigned expression must be a variable or a field");

CLI/Repl.cpp

@@ -10,7 +10,7 @@
 #include "Profiler.h"
 #include "Coverage.h"
 
-#include "linenoise.hpp"
+#include "isocline.h"
 
 #include <memory>
 
@@ -240,9 +240,10 @@ std::string runCode(lua_State* L, const std::string& source)
     return std::string();
 }
 
-static void completeIndexer(lua_State* L, const char* editBuffer, size_t start, std::vector<std::string>& completions)
+static void completeIndexer(ic_completion_env_t* cenv, const char* editBuffer)
 {
-    std::string_view lookup = editBuffer + start;
+    auto* L = reinterpret_cast<lua_State*>(ic_completion_arg(cenv));
+    std::string_view lookup = editBuffer;
     char lastSep = 0;
 
     for (;;)
@@ -268,13 +269,14 @@ static void completeIndexer(lua_State* L, const char* editBuffer, size_t start,
 
                     if (!key.empty() && requiredValueType && Luau::startsWith(key, prefix))
                     {
-                        std::string completion(editBuffer + std::string(key.substr(prefix.size())));
+                        std::string completedComponent(key.substr(prefix.size()));
+                        std::string completion(editBuffer + completedComponent);
                         if (valueType == LUA_TFUNCTION)
                         {
                             // Add an opening paren for function calls by default.
                             completion += "(";
                         }
-                        completions.push_back(completion);
+                        ic_add_completion_ex(cenv, completion.data(), key.data(), nullptr);
                     }
                 }
                 lua_pop(L, 1);
@@ -310,19 +312,23 @@ static void completeIndexer(lua_State* L, const char* editBuffer, size_t start,
     lua_pop(L, 1);
 }
 
-static void completeRepl(lua_State* L, const char* editBuffer, std::vector<std::string>& completions)
+static bool isMethodOrFunctionChar(const char* s, long len)
 {
-    size_t start = strlen(editBuffer);
+    char c = *s;
-    while (start > 0 && (isalnum(editBuffer[start - 1]) || editBuffer[start - 1] == '.' || editBuffer[start - 1] == ':' || editBuffer[start - 1] == '_'))
+    return len == 1 && (isalnum(c) || c == '.' || c == ':' || c == '_');
-        start--;
+}
+
+static void completeRepl(ic_completion_env_t* cenv, const char* editBuffer)
+{
+    auto* L = reinterpret_cast<lua_State*>(ic_completion_arg(cenv));
 
     // look the value up in current global table first
     lua_pushvalue(L, LUA_GLOBALSINDEX);
-    completeIndexer(L, editBuffer, start, completions);
+    ic_complete_word(cenv, editBuffer, completeIndexer, isMethodOrFunctionChar);
 
     // and in actual global table after that
     lua_getglobal(L, "_G");
-    completeIndexer(L, editBuffer, start, completions);
+    ic_complete_word(cenv, editBuffer, completeIndexer, isMethodOrFunctionChar);
 }
 
 struct LinenoiseScopedHistory
@@ -341,13 +347,11 @@ struct LinenoiseScopedHistory
         }
 
         if (!historyFilepath.empty())
-            linenoise::LoadHistory(historyFilepath.c_str());
+            ic_set_history(historyFilepath.c_str(), -1 /* default entries (= 200) */);
     }
 
     ~LinenoiseScopedHistory()
     {
-        if (!historyFilepath.empty())
-            linenoise::SaveHistory(historyFilepath.c_str());
     }
 
     std::string historyFilepath;
@@ -355,28 +359,32 @@ struct LinenoiseScopedHistory
 
 static void runReplImpl(lua_State* L)
 {
-    linenoise::SetCompletionCallback([L](const char* editBuffer, std::vector<std::string>& completions) {
+    ic_set_default_completer(completeRepl, L);
-        completeRepl(L, editBuffer, completions);
+
-    });
+    // Make brace matching easier to see
+    ic_style_def("ic-bracematch", "teal");
+
+    // Prevent auto insertion of braces
+    ic_enable_brace_insertion(false);
 
     std::string buffer;
     LinenoiseScopedHistory scopedHistory;
 
     for (;;)
     {
-        bool quit = false;
+        const char* line = ic_readline(buffer.empty() ? "" : ">");
-        std::string line = linenoise::Readline(buffer.empty() ? "> " : ">> ", quit);
+        if (!line)
-        if (quit)
             break;
 
         if (buffer.empty() && runCode(L, std::string("return ") + line) == std::string())
         {
-            linenoise::AddHistory(line.c_str());
+            ic_history_add(line);
             continue;
         }
 
+        if (!buffer.empty())
+            buffer += "\n";
         buffer += line;
-        buffer += " "; // linenoise doesn't work very well with multiline history entries
 
         std::string error = runCode(L, buffer);
 
@@ -390,8 +398,9 @@ static void runReplImpl(lua_State* L)
             fprintf(stdout, "%s\n", error.c_str());
         }
 
-        linenoise::AddHistory(buffer.c_str());
+        ic_history_add(buffer.c_str());
         buffer.clear();
+        free((void*)line);
     }
 }
 

CLI/ReplEntry.cpp

@@ -1,5 +1,4 @@
 // This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
-
 #include "Repl.h"
 
 

CMakeLists.txt

@@ -5,7 +5,7 @@ if(EXT_PLATFORM_STRING)
 endif()
 
 cmake_minimum_required(VERSION 3.0)
-project(Luau LANGUAGES CXX)
+project(Luau LANGUAGES CXX C)
 
 option(LUAU_BUILD_CLI "Build CLI" ON)
 option(LUAU_BUILD_TESTS "Build tests" ON)
@@ -16,6 +16,7 @@ add_library(Luau.Ast STATIC)
 add_library(Luau.Compiler STATIC)
 add_library(Luau.Analysis STATIC)
 add_library(Luau.VM STATIC)
+add_library(isocline STATIC)
 
 if(LUAU_BUILD_CLI)
     add_executable(Luau.Repl.CLI)
@@ -52,6 +53,8 @@ target_link_libraries(Luau.Analysis PUBLIC Luau.Ast)
 target_compile_features(Luau.VM PRIVATE cxx_std_11)
 target_include_directories(Luau.VM PUBLIC VM/include)
 
+target_include_directories(isocline PUBLIC extern/isocline/include)
+
 set(LUAU_OPTIONS)
 
 if(MSVC)
@@ -75,9 +78,16 @@ if(LUAU_BUILD_WEB)
     list(APPEND LUAU_OPTIONS -fexceptions)
 endif()
 
+set(ISOCLINE_OPTIONS)
+
+if (NOT MSVC)
+    list(APPEND ISOCLINE_OPTIONS -Wno-unused-function)
+endif()
+
 target_compile_options(Luau.Ast PRIVATE ${LUAU_OPTIONS})
 target_compile_options(Luau.Analysis PRIVATE ${LUAU_OPTIONS})
 target_compile_options(Luau.VM PRIVATE ${LUAU_OPTIONS})
+target_compile_options(isocline PRIVATE ${LUAU_OPTIONS} ${ISOCLINE_OPTIONS})
 
 if (MSVC AND MSVC_VERSION GREATER_EQUAL 1924)
     # disable partial redundancy elimination which regresses interpreter codegen substantially in VS2022:
@@ -89,8 +99,9 @@ if(LUAU_BUILD_CLI)
     target_compile_options(Luau.Repl.CLI PRIVATE ${LUAU_OPTIONS})
     target_compile_options(Luau.Analyze.CLI PRIVATE ${LUAU_OPTIONS})
 
-    target_include_directories(Luau.Repl.CLI PRIVATE extern)
+    target_include_directories(Luau.Repl.CLI PRIVATE extern extern/isocline/include)
-    target_link_libraries(Luau.Repl.CLI PRIVATE Luau.Compiler Luau.VM)
+
+    target_link_libraries(Luau.Repl.CLI PRIVATE Luau.Compiler Luau.VM isocline)
 
     if(UNIX)
         find_library(LIBPTHREAD pthread)
@@ -113,7 +124,7 @@ if(LUAU_BUILD_TESTS)
 
     target_compile_options(Luau.CLI.Test PRIVATE ${LUAU_OPTIONS})
     target_include_directories(Luau.CLI.Test PRIVATE extern CLI)
-    target_link_libraries(Luau.CLI.Test PRIVATE Luau.Compiler Luau.VM)
+    target_link_libraries(Luau.CLI.Test PRIVATE Luau.Compiler Luau.VM isocline)
     if(UNIX)
         find_library(LIBPTHREAD pthread)
         if (LIBPTHREAD)

Compiler/src/Builtins.cpp

@@ -4,7 +4,7 @@
 #include "Luau/Bytecode.h"
 #include "Luau/Compiler.h"
 
-LUAU_FASTFLAGVARIABLE(LuauCompileSelectBuiltin, false)
+LUAU_FASTFLAGVARIABLE(LuauCompileSelectBuiltin2, false)
 
 namespace Luau
 {
@@ -64,7 +64,7 @@ int getBuiltinFunctionId(const Builtin& builtin, const CompileOptions& options)
     if (builtin.isGlobal("unpack"))
         return LBF_TABLE_UNPACK;
 
-    if (FFlag::LuauCompileSelectBuiltin && builtin.isGlobal("select"))
+    if (FFlag::LuauCompileSelectBuiltin2 && builtin.isGlobal("select"))
         return LBF_SELECT_VARARG;
 
     if (builtin.object == "math")

Compiler/src/Compiler.cpp

@@ -16,7 +16,7 @@
 #include <math.h>
 
 LUAU_FASTFLAGVARIABLE(LuauCompileTableIndexOpt, false)
-LUAU_FASTFLAG(LuauCompileSelectBuiltin)
+LUAU_FASTFLAG(LuauCompileSelectBuiltin2)
 
 namespace Luau
 {
@@ -266,7 +266,7 @@ struct Compiler
 
     void compileExprSelectVararg(AstExprCall* expr, uint8_t target, uint8_t targetCount, bool targetTop, bool multRet, uint8_t regs)
     {
-        LUAU_ASSERT(FFlag::LuauCompileSelectBuiltin);
+        LUAU_ASSERT(FFlag::LuauCompileSelectBuiltin2);
         LUAU_ASSERT(targetCount == 1);
         LUAU_ASSERT(!expr->self);
         LUAU_ASSERT(expr->args.size == 2 && expr->args.data[1]->is<AstExprVarargs>());
@@ -291,6 +291,9 @@ struct Compiler
         // we can't use TempTop variant here because we need to make sure the arguments we already computed aren't overwritten
         compileExprTemp(expr->func, regs);
 
+        if (argreg != regs + 1)
+            bytecode.emitABC(LOP_MOVE, uint8_t(regs + 1), argreg, 0);
+
         bytecode.emitABC(LOP_GETVARARGS, uint8_t(regs + 2), 0, 0);
 
         size_t callLabel = bytecode.emitLabel();
@@ -405,7 +408,7 @@ struct Compiler
 
         if (bfid == LBF_SELECT_VARARG)
         {
-            LUAU_ASSERT(FFlag::LuauCompileSelectBuiltin);
+            LUAU_ASSERT(FFlag::LuauCompileSelectBuiltin2);
             // Optimization: compile select(_, ...) as FASTCALL1; the builtin will read variadic arguments directly
             // note: for now we restrict this to single-return expressions since our runtime code doesn't deal with general cases
             if (multRet == false && targetCount == 1 && expr->args.size == 2 && expr->args.data[1]->is<AstExprVarargs>())

Compiler/src/TableShape.cpp

@@ -1,8 +1,6 @@
 // This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
 #include "TableShape.h"
 
-LUAU_FASTFLAGVARIABLE(LuauPredictTableSizeLoop, false)
-
 namespace Luau
 {
 namespace Compile
@@ -87,9 +85,6 @@ struct ShapeVisitor : AstVisitor
         }
         else if (AstExprLocal* iter = index->as<AstExprLocal>())
         {
-            if (!FFlag::LuauPredictTableSizeLoop)
-                return;
-
             if (const unsigned int* bound = loops.find(iter->local))
             {
                 TableShape& shape = shapes[*table];
@@ -143,9 +138,6 @@ struct ShapeVisitor : AstVisitor
 
     bool visit(AstStatFor* node) override
     {
-        if (!FFlag::LuauPredictTableSizeLoop)
-            return true;
-
         AstExprConstantNumber* from = node->from->as<AstExprConstantNumber>();
         AstExprConstantNumber* to = node->to->as<AstExprConstantNumber>();
 

Makefile

@@ -23,6 +23,10 @@ VM_SOURCES=$(wildcard VM/src/*.cpp)
 VM_OBJECTS=$(VM_SOURCES:%=$(BUILD)/%.o)
 VM_TARGET=$(BUILD)/libluauvm.a
 
+ISOCLINE_SOURCES=extern/isocline/src/isocline.c
+ISOCLINE_OBJECTS=$(ISOCLINE_SOURCES:%=$(BUILD)/%.o)
+ISOCLINE_TARGET=$(BUILD)/libisocline.a
+
 TESTS_SOURCES=$(wildcard tests/*.cpp) CLI/FileUtils.cpp CLI/Profiler.cpp CLI/Coverage.cpp CLI/Repl.cpp
 TESTS_OBJECTS=$(TESTS_SOURCES:%=$(BUILD)/%.o)
 TESTS_TARGET=$(BUILD)/luau-tests
@@ -43,7 +47,7 @@ ifneq ($(flags),)
 	TESTS_ARGS+=--fflags=$(flags)
 endif
 
-OBJECTS=$(AST_OBJECTS) $(COMPILER_OBJECTS) $(ANALYSIS_OBJECTS) $(VM_OBJECTS) $(TESTS_OBJECTS) $(CLI_OBJECTS) $(FUZZ_OBJECTS)
+OBJECTS=$(AST_OBJECTS) $(COMPILER_OBJECTS) $(ANALYSIS_OBJECTS) $(VM_OBJECTS) $(ISOCLINE_OBJECTS) $(TESTS_OBJECTS) $(CLI_OBJECTS) $(FUZZ_OBJECTS)
 
 # common flags
 CXXFLAGS=-g -Wall
@@ -90,8 +94,9 @@ $(AST_OBJECTS): CXXFLAGS+=-std=c++17 -IAst/include
 $(COMPILER_OBJECTS): CXXFLAGS+=-std=c++17 -ICompiler/include -IAst/include
 $(ANALYSIS_OBJECTS): CXXFLAGS+=-std=c++17 -IAst/include -IAnalysis/include
 $(VM_OBJECTS): CXXFLAGS+=-std=c++11 -IVM/include
+$(ISOCLINE_OBJECTS): CXXFLAGS+=-Wno-unused-function -Iextern/isocline/include
 $(TESTS_OBJECTS): CXXFLAGS+=-std=c++17 -IAst/include -ICompiler/include -IAnalysis/include -IVM/include -ICLI -Iextern
-$(REPL_CLI_OBJECTS): CXXFLAGS+=-std=c++17 -IAst/include -ICompiler/include -IVM/include -Iextern
+$(REPL_CLI_OBJECTS): CXXFLAGS+=-std=c++17 -IAst/include -ICompiler/include -IVM/include -Iextern -Iextern/isocline/include
 $(ANALYZE_CLI_OBJECTS): CXXFLAGS+=-std=c++17 -IAst/include -IAnalysis/include -Iextern
 $(FUZZ_OBJECTS): CXXFLAGS+=-std=c++17 -IAst/include -ICompiler/include -IAnalysis/include -IVM/include
 
@@ -116,9 +121,9 @@ coverage: $(TESTS_TARGET)
 	$(TESTS_TARGET)
 	llvm-profdata merge default.profraw default-flags.profraw -o default.profdata
 	rm default.profraw default-flags.profraw
-	llvm-cov show -format=html -show-instantiations=false -show-line-counts=true -show-region-summary=false -ignore-filename-regex=\(tests\|extern\)/.* -output-dir=coverage --instr-profile default.profdata build/coverage/luau-tests
+	llvm-cov show -format=html -show-instantiations=false -show-line-counts=true -show-region-summary=false -ignore-filename-regex=\(tests\|extern\|CLI\)/.* -output-dir=coverage --instr-profile default.profdata build/coverage/luau-tests
-	llvm-cov report -ignore-filename-regex=\(tests\|extern\)/.* -show-region-summary=false --instr-profile default.profdata build/coverage/luau-tests
+	llvm-cov report -ignore-filename-regex=\(tests\|extern\|CLI\)/.* -show-region-summary=false --instr-profile default.profdata build/coverage/luau-tests
-	llvm-cov export -ignore-filename-regex=\(tests\|extern\)/.* -format lcov --instr-profile default.profdata build/coverage/luau-tests >coverage.info
+	llvm-cov export -ignore-filename-regex=\(tests\|extern\|CLI\)/.* -format lcov --instr-profile default.profdata build/coverage/luau-tests >coverage.info
 
 format:
 	find . -name '*.h' -or -name '*.cpp' | xargs clang-format -i
@@ -135,8 +140,8 @@ luau-analyze: $(ANALYZE_CLI_TARGET)
 	ln -fs $^ $@
 
 # executable targets
-$(TESTS_TARGET): $(TESTS_OBJECTS) $(ANALYSIS_TARGET) $(COMPILER_TARGET) $(AST_TARGET) $(VM_TARGET)
+$(TESTS_TARGET): $(TESTS_OBJECTS) $(ANALYSIS_TARGET) $(COMPILER_TARGET) $(AST_TARGET) $(VM_TARGET) $(ISOCLINE_TARGET)
-$(REPL_CLI_TARGET): $(REPL_CLI_OBJECTS) $(COMPILER_TARGET) $(AST_TARGET) $(VM_TARGET)
+$(REPL_CLI_TARGET): $(REPL_CLI_OBJECTS) $(COMPILER_TARGET) $(AST_TARGET) $(VM_TARGET) $(ISOCLINE_TARGET)
 $(ANALYZE_CLI_TARGET): $(ANALYZE_CLI_OBJECTS) $(ANALYSIS_TARGET) $(AST_TARGET)
 
 $(TESTS_TARGET) $(REPL_CLI_TARGET) $(ANALYZE_CLI_TARGET):
@@ -154,8 +159,9 @@ $(AST_TARGET): $(AST_OBJECTS)
 $(COMPILER_TARGET): $(COMPILER_OBJECTS)
 $(ANALYSIS_TARGET): $(ANALYSIS_OBJECTS)
 $(VM_TARGET): $(VM_OBJECTS)
+$(ISOCLINE_TARGET): $(ISOCLINE_OBJECTS)
 
-$(AST_TARGET) $(COMPILER_TARGET) $(ANALYSIS_TARGET) $(VM_TARGET):
+$(AST_TARGET) $(COMPILER_TARGET) $(ANALYSIS_TARGET) $(VM_TARGET) $(ISOCLINE_TARGET):
 	ar rcs $@ $^
 
 # object file targets
@@ -163,6 +169,10 @@ $(BUILD)/%.cpp.o: %.cpp
 	@mkdir -p $(dir $@)
 	$(CXX) $< $(CXXFLAGS) -c -MMD -MP -o $@
 
+$(BUILD)/%.c.o: %.c
+	@mkdir -p $(dir $@)
+	$(CXX) -x c $< $(CXXFLAGS) -c -MMD -MP -o $@
+
 # protobuf fuzzer setup
 fuzz/luau.pb.cpp: fuzz/luau.proto build/libprotobuf-mutator
 	cd fuzz && ../build/libprotobuf-mutator/external.protobuf/bin/protoc luau.proto --cpp_out=.

Sources.cmake

@@ -167,6 +167,11 @@ target_sources(Luau.VM PRIVATE
     VM/src/lvm.h
 )
 
+target_sources(isocline PRIVATE
+    extern/isocline/include/isocline.h
+    extern/isocline/src/isocline.c
+)
+
 if(TARGET Luau.Repl.CLI)
     # Luau.Repl.CLI Sources
     target_sources(Luau.Repl.CLI PRIVATE

VM/src/ldebug.cpp

@@ -12,7 +12,6 @@
 #include <string.h>
 #include <stdio.h>
 
-LUAU_FASTFLAG(LuauBytecodeV2Read)
 LUAU_FASTFLAG(LuauBytecodeV2Force)
 
 static const char* getfuncname(Closure* f);
@@ -96,7 +95,7 @@ static int getlinedefined(Proto* p)
 {
     if (FFlag::LuauBytecodeV2Force)
         return p->linedefined;
-    else if (FFlag::LuauBytecodeV2Read && p->linedefined >= 0)
+    else if (p->linedefined >= 0)
         return p->linedefined;
     else
         return luaG_getline(p, 0);

VM/src/lgc.cpp

@@ -759,6 +759,8 @@ static int sweepgcopage(lua_State* L, lua_Page* page)
         // when true is returned it means that the element was deleted
         if (sweepgco(L, page, gco))
         {
+            LUAU_ASSERT(busyBlocks > 0);
+
             // if the last block was removed, page would be removed as well
             if (--busyBlocks == 0)
                 return int(pos - start) / blockSize + 1;

VM/src/lmem.cpp

@@ -57,8 +57,7 @@ const size_t kSizeClasses = LUA_SIZECLASSES;
 const size_t kMaxSmallSize = 512;
 const size_t kPageSize = 16 * 1024 - 24; // slightly under 16KB since that results in less fragmentation due to heap metadata
 const size_t kBlockHeader = sizeof(double) > sizeof(void*) ? sizeof(double) : sizeof(void*); // suitable for aligning double & void* on all platforms
-// TODO (FFlagLuauGcPagedSweep): when 'next' is removed, 'kBlockHeader' can be used unconditionally
+const size_t kGCOLinkOffset = (sizeof(GCheader) + sizeof(void*) - 1) & ~(sizeof(void*) - 1); // GCO pages contain freelist links after the GC header
-const size_t kGCOHeader = sizeof(GCheader) > kBlockHeader ? sizeof(GCheader) : kBlockHeader;
 
 struct SizeClassConfig
 {
@@ -101,12 +100,12 @@ struct SizeClassConfig
 
 const SizeClassConfig kSizeClassConfig;
 
-// size class for a block of size sz
+// size class for a block of size sz; returns -1 for size=0 because empty allocations take no space
 #define sizeclass(sz) (size_t((sz)-1) < kMaxSmallSize ? kSizeClassConfig.classForSize[sz] : -1)
 
 // metadata for a block is stored in the first pointer of the block
 #define metadata(block) (*(void**)(block))
-#define freegcolink(block) (*(void**)((char*)block + kGCOHeader))
+#define freegcolink(block) (*(void**)((char*)block + kGCOLinkOffset))
 
 /*
 ** About the realloc function:
@@ -157,7 +156,7 @@ l_noret luaM_toobig(lua_State* L)
     luaG_runerror(L, "memory allocation error: block too big");
 }
 
-static lua_Page* luaM_newpage(lua_State* L, uint8_t sizeClass)
+static lua_Page* newpageold(lua_State* L, uint8_t sizeClass)
 {
     LUAU_ASSERT(!FFlag::LuauGcPagedSweep);
 
@@ -253,7 +252,7 @@ static lua_Page* newclasspage(lua_State* L, lua_Page** freepageset, lua_Page** g
     return page;
 }
 
-static void luaM_freepage(lua_State* L, lua_Page* page, uint8_t sizeClass)
+static void freepageold(lua_State* L, lua_Page* page, uint8_t sizeClass)
 {
     LUAU_ASSERT(!FFlag::LuauGcPagedSweep);
 
@@ -310,7 +309,7 @@ static void freeclasspage(lua_State* L, lua_Page** freepageset, lua_Page** gcopa
     freepage(L, gcopageset, page);
 }
 
-static void* luaM_newblock(lua_State* L, int sizeClass)
+static void* newblock(lua_State* L, int sizeClass)
 {
     global_State* g = L->global;
     lua_Page* page = g->freepages[sizeClass];
@@ -321,7 +320,7 @@ static void* luaM_newblock(lua_State* L, int sizeClass)
         if (FFlag::LuauGcPagedSweep)
             page = newclasspage(L, g->freepages, NULL, sizeClass, true);
         else
-            page = luaM_newpage(L, sizeClass);
+            page = newpageold(L, sizeClass);
     }
 
     LUAU_ASSERT(!page->prev);
@@ -363,7 +362,7 @@ static void* luaM_newblock(lua_State* L, int sizeClass)
     return (char*)block + kBlockHeader;
 }
 
-static void* luaM_newgcoblock(lua_State* L, int sizeClass)
+static void* newgcoblock(lua_State* L, int sizeClass)
 {
     LUAU_ASSERT(FFlag::LuauGcPagedSweep);
 
@@ -390,11 +389,10 @@ static void* luaM_newgcoblock(lua_State* L, int sizeClass)
     }
     else
     {
+        block = page->freeList;
+        ASAN_UNPOISON_MEMORY_REGION((char*)block + sizeof(GCheader), page->blockSize - sizeof(GCheader));
+
         // when separate block metadata is not used, free list link is stored inside the block data itself
-        block = (char*)page->freeList - kGCOHeader;
-
-        ASAN_UNPOISON_MEMORY_REGION((char*)block + kGCOHeader, page->blockSize - kGCOHeader);
-
         page->freeList = freegcolink(block);
         page->busyBlocks++;
     }
@@ -412,7 +410,7 @@ static void* luaM_newgcoblock(lua_State* L, int sizeClass)
     return (char*)block;
 }
 
-static void luaM_freeblock(lua_State* L, int sizeClass, void* block)
+static void freeblock(lua_State* L, int sizeClass, void* block)
 {
     global_State* g = L->global;
 
@@ -450,11 +448,11 @@ static void luaM_freeblock(lua_State* L, int sizeClass, void* block)
         if (FFlag::LuauGcPagedSweep)
             freeclasspage(L, g->freepages, NULL, page, sizeClass);
         else
-            luaM_freepage(L, page, sizeClass);
+            freepageold(L, page, sizeClass);
     }
 }
 
-static void luaM_freegcoblock(lua_State* L, int sizeClass, void* block, lua_Page* page)
+static void freegcoblock(lua_State* L, int sizeClass, void* block, lua_Page* page)
 {
     LUAU_ASSERT(FFlag::LuauGcPagedSweep);
 
@@ -474,9 +472,9 @@ static void luaM_freegcoblock(lua_State* L, int sizeClass, void* block, lua_Page
 
     // when separate block metadata is not used, free list link is stored inside the block data itself
     freegcolink(block) = page->freeList;
-    page->freeList = (char*)block + kGCOHeader;
+    page->freeList = block;
 
-    ASAN_POISON_MEMORY_REGION((char*)block + kGCOHeader, page->blockSize - kGCOHeader);
+    ASAN_POISON_MEMORY_REGION((char*)block + sizeof(GCheader), page->blockSize - sizeof(GCheader));
 
     page->busyBlocks--;
 
@@ -491,7 +489,7 @@ void* luaM_new_(lua_State* L, size_t nsize, uint8_t memcat)
 
     int nclass = sizeclass(nsize);
 
-    void* block = nclass >= 0 ? luaM_newblock(L, nclass) : (*g->frealloc)(L, g->ud, NULL, 0, nsize);
+    void* block = nclass >= 0 ? newblock(L, nclass) : (*g->frealloc)(L, g->ud, NULL, 0, nsize);
     if (block == NULL && nsize > 0)
         luaD_throw(L, LUA_ERRMEM);
 
@@ -506,6 +504,9 @@ GCObject* luaM_newgco_(lua_State* L, size_t nsize, uint8_t memcat)
     if (!FFlag::LuauGcPagedSweep)
         return (GCObject*)luaM_new_(L, nsize, memcat);
 
+    // we need to accommodate space for link for free blocks (freegcolink)
+    LUAU_ASSERT(nsize >= kGCOLinkOffset + sizeof(void*));
+
     global_State* g = L->global;
 
     int nclass = sizeclass(nsize);
@@ -514,9 +515,7 @@ GCObject* luaM_newgco_(lua_State* L, size_t nsize, uint8_t memcat)
 
     if (nclass >= 0)
     {
-        LUAU_ASSERT(nsize > 8);
+        block = newgcoblock(L, nclass);
-
-        block = luaM_newgcoblock(L, nclass);
     }
     else
     {
@@ -546,7 +545,7 @@ void luaM_free_(lua_State* L, void* block, size_t osize, uint8_t memcat)
     int oclass = sizeclass(osize);
 
     if (oclass >= 0)
-        luaM_freeblock(L, oclass, block);
+        freeblock(L, oclass, block);
     else
         (*g->frealloc)(L, g->ud, block, osize, 0);
 
@@ -571,7 +570,7 @@ void luaM_freegco_(lua_State* L, GCObject* block, size_t osize, uint8_t memcat,
     {
         block->gch.tt = LUA_TNIL;
 
-        luaM_freegcoblock(L, oclass, block, page);
+        freegcoblock(L, oclass, block, page);
     }
     else
     {
@@ -596,7 +595,7 @@ void* luaM_realloc_(lua_State* L, void* block, size_t osize, size_t nsize, uint8
     // if either block needs to be allocated using a block allocator, we can't use realloc directly
     if (nclass >= 0 || oclass >= 0)
     {
-        result = nclass >= 0 ? luaM_newblock(L, nclass) : (*g->frealloc)(L, g->ud, NULL, 0, nsize);
+        result = nclass >= 0 ? newblock(L, nclass) : (*g->frealloc)(L, g->ud, NULL, 0, nsize);
         if (result == NULL && nsize > 0)
             luaD_throw(L, LUA_ERRMEM);
 
@@ -604,7 +603,7 @@ void* luaM_realloc_(lua_State* L, void* block, size_t osize, size_t nsize, uint8
             memcpy(result, block, osize < nsize ? osize : nsize);
 
         if (oclass >= 0)
-            luaM_freeblock(L, oclass, block);
+            freeblock(L, oclass, block);
         else
             (*g->frealloc)(L, g->ud, block, osize, 0);
     }
@@ -659,6 +658,8 @@ void luaM_visitpage(lua_Page* page, void* context, bool (*visitor)(void* context
         // when true is returned it means that the element was deleted
         if (visitor(context, page, gco))
         {
+            LUAU_ASSERT(busyBlocks > 0);
+
             // if the last block was removed, page would be removed as well
             if (--busyBlocks == 0)
                 break;

VM/src/lvmexecute.cpp

@@ -676,14 +676,9 @@ static void luau_execute(lua_State* L)
                         VM_PROTECT_PC(); // set may fail
 
                         TValue* res = luaH_setstr(L, h, tsvalue(kv));
-
-                        if (res != luaO_nilobject)
-                        {
                         int cachedslot = gval2slot(h, res);
                         // save cachedslot to accelerate future lookups; patches currently executing instruction since pc-2 rolls back two pc++
                         VM_PATCH_C(pc - 2, cachedslot);
-                        }
-
                         setobj(L, res, ra);
                         luaC_barriert(L, h, ra);
                         VM_NEXT();

VM/src/lvmload.cpp

@@ -13,7 +13,6 @@
 
 #include <string.h>
 
-LUAU_FASTFLAGVARIABLE(LuauBytecodeV2Read, true)
 LUAU_FASTFLAGVARIABLE(LuauBytecodeV2Force, false)
 
 // TODO: RAII deallocation doesn't work for longjmp builds if a memory error happens
@@ -157,11 +156,12 @@ int luau_load(lua_State* L, const char* chunkname, const char* data, size_t size
         return 1;
     }
 
-    if (FFlag::LuauBytecodeV2Force ? (version != LBC_VERSION_FUTURE) : FFlag::LuauBytecodeV2Read ? (version != LBC_VERSION && version != LBC_VERSION_FUTURE) : (version != LBC_VERSION))
+    if (FFlag::LuauBytecodeV2Force ? (version != LBC_VERSION_FUTURE) : (version != LBC_VERSION && version != LBC_VERSION_FUTURE))
     {
         char chunkid[LUA_IDSIZE];
         luaO_chunkid(chunkid, chunkname, LUA_IDSIZE);
-        lua_pushfstring(L, "%s: bytecode version mismatch (expected %d, got %d)", chunkid, FFlag::LuauBytecodeV2Force ? LBC_VERSION_FUTURE : LBC_VERSION, version);
+        lua_pushfstring(L, "%s: bytecode version mismatch (expected %d, got %d)", chunkid,
+            FFlag::LuauBytecodeV2Force ? LBC_VERSION_FUTURE : LBC_VERSION, version);
         return 1;
     }
 
@@ -292,7 +292,7 @@ int luau_load(lua_State* L, const char* chunkname, const char* data, size_t size
             p->p[j] = protos[fid];
         }
 
-        if (FFlag::LuauBytecodeV2Force || (FFlag::LuauBytecodeV2Read && version == LBC_VERSION_FUTURE))
+        if (FFlag::LuauBytecodeV2Force || version == LBC_VERSION_FUTURE)
             p->linedefined = readVarInt(data, size, offset);
         else
             p->linedefined = -1;

extern/isocline/.gitignore

@@ -0,0 +1,16 @@
+out/
+build/
+dist/
+doc/html/
+.vs/
+.vscode/
+.stack-work/
+.DS_Store
+*.user
+*.exe
+*.hi
+*.o
+*_stub.h
+*.lock
+history.txt
+isocline.debug.txt

extern/isocline/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2021 Daan Leijen
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

extern/isocline/include/isocline.h

@@ -0,0 +1,627 @@
+/* ----------------------------------------------------------------------------
+  Copyright (c) 2021, Daan Leijen
+  This is free software; you can redistribute it and/or modify it
+  under the terms of the MIT License. A copy of the license can be
+  found in the "LICENSE" file at the root of this distribution.
+-----------------------------------------------------------------------------*/
+#pragma once
+#ifndef IC_ISOCLINE_H
+#define IC_ISOCLINE_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stddef.h>    // size_t
+#include <stdbool.h>   // bool
+#include <stdint.h>    // uint32_t
+#include <stdarg.h>    // term_vprintf
+
+
+/*! \mainpage
+Isocline C API reference.
+
+Isocline is a pure C library that can be used as an alternative to the GNU readline library.
+
+See the [Github repository](https://github.com/daanx/isocline#readme) 
+for general information and building the library.
+
+Contents:
+- \ref readline
+- \ref bbcode
+- \ref history
+- \ref completion
+- \ref highlight
+- \ref options
+- \ref helper
+- \ref completex
+- \ref term
+- \ref async
+- \ref alloc
+*/
+
+/// \defgroup readline Readline
+/// The basic readline interface.
+/// \{
+
+/// Isocline version: 102 = 1.0.2.
+#define IC_VERSION   (104)  
+
+
+/// Read input from the user using rich editing abilities.
+/// @param prompt_text   The prompt text, can be NULL for the default (""). 
+///   The displayed prompt becomes `prompt_text` followed by the `prompt_marker` ("> "). 
+/// @returns the heap allocated input on succes, which should be `free`d by the caller.  
+///   Returns NULL on error, or if the user typed ctrl+d or ctrl+c.
+///
+/// If the standard input (`stdin`) has no editing capability 
+/// (like a dumb terminal (e.g. `TERM`=`dumb`), running in a debuggen, a pipe or redirected file, etc.)
+/// the input is read directly from the input stream up to the 
+/// next line without editing capability.
+/// See also \a ic_set_prompt_marker(), \a ic_style_def()
+///
+/// @see ic_set_prompt_marker(), ic_style_def()
+char* ic_readline(const char* prompt_text);   
+
+/// \}
+
+
+//--------------------------------------------------------------
+/// \defgroup bbcode Formatted Text
+/// Formatted text using [bbcode markup](https://github.com/daanx/isocline#bbcode-format).
+/// \{
+
+/// Print to the terminal while respection bbcode markup. 
+/// Any unclosed tags are closed automatically at the end of the print.
+/// For example:
+/// ```
+/// ic_print("[b]bold, [i]bold and italic[/i], [red]red and bold[/][/b] default.");
+/// ic_print("[b]bold[/], [i b]bold and italic[/], [yellow on blue]yellow on blue background");
+/// ic_style_add("em","i color=#888800");
+/// ic_print("[em]emphasis");
+/// ```
+/// Properties that can be assigned are:
+/// * `color=` _clr_, `bgcolor=` _clr_: where _clr_ is either a hex value `#`RRGGBB or `#`RGB, a
+///    standard HTML color name, or an ANSI palette name, like `ansi-maroon`, `ansi-default`, etc.
+/// * `bold`,`italic`,`reverse`,`underline`: can be `on` or `off`. 
+/// * everything else is a style; all HTML and ANSI color names are also a style (so we can just use `red`
+///   instead of `color=red`, or `on red` instead of `bgcolor=red`), and there are
+///   the `b`, `i`, `u`, and `r` styles for bold, italic, underline, and reverse.
+/// 
+/// See [here](https://github.com/daanx/isocline#bbcode-format) for a description of the full bbcode format.
+void ic_print( const char* s );
+
+/// Print with bbcode markup ending with a newline.
+/// @see ic_print()
+void ic_println( const char* s );
+
+/// Print formatted with bbcode markup.
+/// @see ic_print()
+void ic_printf(const char* fmt, ...);
+
+/// Print formatted with bbcode markup.
+/// @see ic_print
+void ic_vprintf(const char* fmt, va_list args);
+
+/// Define or redefine a style.
+/// @param style_name The name of the style. 
+/// @param fmt        The `fmt` string is the content of a tag and can contain
+///   other styles. This is very useful to theme the output of a program
+///   by assigning standard styles like `em` or `warning` etc.
+void ic_style_def( const char* style_name, const char* fmt );
+
+/// Start a global style that is only reset when calling a matching ic_style_close().
+void ic_style_open( const char* fmt );
+
+/// End a global style.
+void ic_style_close(void);
+
+/// \}
+
+
+//--------------------------------------------------------------
+// History
+//--------------------------------------------------------------
+/// \defgroup history History
+/// Readline input history.
+/// \{
+
+/// Enable history. 
+/// Use a \a NULL filename to not persist the history. Use -1 for max_entries to get the default (200).
+void ic_set_history(const char* fname, long max_entries );
+
+/// Remove the last entry in the history. 
+/// The last returned input from ic_readline() is automatically added to the history; this function removes it.
+void ic_history_remove_last(void);
+
+/// Clear the history.
+void ic_history_clear(void);
+
+/// Add an entry to the history
+void ic_history_add( const char* entry );
+
+/// \}
+
+//--------------------------------------------------------------
+// Basic Completion
+//--------------------------------------------------------------
+
+/// \defgroup completion Completion
+/// Basic word completion.
+/// \{
+
+/// A completion environment
+struct ic_completion_env_s;
+
+/// A completion environment
+typedef struct ic_completion_env_s ic_completion_env_t;
+
+/// A completion callback that is called by isocline when tab is pressed.
+/// It is passed a completion environment (containing the current input and the current cursor position), 
+/// the current input up-to the cursor (`prefix`)
+/// and the user given argument when the callback was set.
+/// When using completion transformers, like `ic_complete_quoted_word` the `prefix` contains the
+/// the word to be completed without escape characters or quotes.
+typedef void (ic_completer_fun_t)(ic_completion_env_t* cenv, const char* prefix );
+
+/// Set the default completion handler.
+/// @param completer  The completion function
+/// @param arg        Argument passed to the \a completer.
+/// There can only be one default completion function, setting it again disables the previous one.
+/// The initial completer use `ic_complete_filename`.
+void ic_set_default_completer( ic_completer_fun_t* completer, void* arg);
+
+
+/// In a completion callback (usually from ic_complete_word()), use this function to add a completion.
+/// (the completion string is copied by isocline and do not need to be preserved or allocated).
+///
+/// Returns `true` if the callback should continue trying to find more possible completions.
+/// If `false` is returned, the callback should try to return and not add more completions (for improved latency).
+bool ic_add_completion(ic_completion_env_t* cenv, const char* completion);
+
+/// In a completion callback (usually from ic_complete_word()), use this function to add a completion.
+/// The `display` is used to display the completion in the completion menu, and `help` is
+/// displayed for hints for example. Both can be `NULL` for the default.
+/// (all are copied by isocline and do not need to be preserved or allocated).
+///
+/// Returns `true` if the callback should continue trying to find more possible completions.
+/// If `false` is returned, the callback should try to return and not add more completions (for improved latency).
+bool ic_add_completion_ex( ic_completion_env_t* cenv, const char* completion, const char* display, const char* help );
+
+/// In a completion callback (usually from ic_complete_word()), use this function to add completions.
+/// The `completions` array should be terminated with a NULL element, and all elements
+/// are added as completions if they start with `prefix`.
+///
+/// Returns `true` if the callback should continue trying to find more possible completions.
+/// If `false` is returned, the callback should try to return and not add more completions (for improved latency).
+bool ic_add_completions(ic_completion_env_t* cenv, const char* prefix, const char** completions);
+
+/// Complete a filename.
+/// Complete a filename given a semi-colon separated list of root directories `roots` and 
+/// semi-colon separated list of possible extensions (excluding directories). 
+/// If `roots` is NULL, the current directory is the root ("."). 
+/// If `extensions` is NULL, any extension will match.
+/// Each root directory should _not_ end with a directory separator.
+/// If a directory is completed, the `dir_separator` is added at the end if it is not `0`.
+/// Usually the `dir_separator` is `/` but it can be set to `\\` on Windows systems.
+/// For example:
+/// ```
+/// /ho         --> /home/
+/// /home/.ba   --> /home/.bashrc
+/// ```
+/// (This already uses ic_complete_quoted_word() so do not call it from inside a word handler).
+void ic_complete_filename( ic_completion_env_t* cenv, const char* prefix, char dir_separator, const char* roots, const char* extensions );
+
+
+
+/// Function that returns whether a (utf8) character (of length `len`) is in a certain character class
+/// @see ic_char_is_separator() etc.
+typedef bool (ic_is_char_class_fun_t)(const char* s, long len);
+
+
+/// Complete a _word_ (i.e. _token_). 
+/// Calls the user provided function `fun` to complete on the
+/// current _word_. Almost all user provided completers should use this function. 
+/// If `is_word_char` is NULL, the default `&ic_char_is_nonseparator` is used. 
+/// The `prefix` passed to `fun` is modified to only contain the current word, and 
+/// any results from `ic_add_completion` are automatically adjusted to replace that part.
+/// For example, on the input "hello w", a the user `fun` only gets `w` and can just complete
+/// with "world" resulting in "hello world" without needing to consider `delete_before` etc.
+/// @see ic_complete_qword() for completing quoted and escaped tokens.
+void ic_complete_word(ic_completion_env_t* cenv, const char* prefix, ic_completer_fun_t* fun, ic_is_char_class_fun_t* is_word_char);
+
+
+/// Complete a quoted _word_. 
+/// Calls the user provided function `fun` to complete while taking
+/// care of quotes and escape characters. Almost all user provided completers should use
+/// this function. The `prefix` passed to `fun` is modified to be unquoted and unescaped, and 
+/// any results from `ic_add_completion` are automatically quoted and escaped again.
+/// For example, completing `hello world`, the `fun` always just completes `hel` or `hello w` to `hello world`, 
+/// but depending on user input, it will complete as:
+/// ```
+/// hel        -->  hello\ world
+/// hello\ w   -->  hello\ world
+/// hello w    -->                   # no completion, the word is just 'w'>
+/// "hel       -->  "hello world" 
+/// "hello w   -->  "hello world"
+/// ```
+/// with proper quotes and escapes.
+/// If `is_word_char` is NULL, the default `&ic_char_is_nonseparator` is used. 
+/// @see ic_complete_quoted_word() to customize the word boundary, quotes etc.
+void ic_complete_qword( ic_completion_env_t* cenv, const char* prefix, ic_completer_fun_t* fun, ic_is_char_class_fun_t* is_word_char );
+
+
+
+/// Complete a _word_. 
+/// Calls the user provided function `fun` to complete while taking
+/// care of quotes and escape characters. Almost all user provided completers should use this function. 
+/// The `is_word_char` is a set of characters that are part of a "word". Use NULL for the default (`&ic_char_is_nonseparator`).
+/// The `escape_char` is the escaping character, usually `\` but use 0 to not have escape characters.
+/// The `quote_chars` define the quotes, use NULL for the default `"\'\""` quotes.
+/// @see ic_complete_word() which uses the default values for `non_word_chars`, `quote_chars` and `\` for escape characters.
+void ic_complete_qword_ex( ic_completion_env_t* cenv, const char* prefix, ic_completer_fun_t fun, 
+                                ic_is_char_class_fun_t* is_word_char, char escape_char, const char* quote_chars );
+
+/// \}
+
+//--------------------------------------------------------------
+/// \defgroup highlight Syntax Highlighting
+/// Basic syntax highlighting.
+/// \{
+
+/// A syntax highlight environment
+struct ic_highlight_env_s;
+typedef struct ic_highlight_env_s ic_highlight_env_t;
+
+/// A syntax highlighter callback that is called by readline to syntax highlight user input.
+typedef void (ic_highlight_fun_t)(ic_highlight_env_t* henv, const char* input, void* arg);
+
+/// Set a syntax highlighter.
+/// There can only be one highlight function, setting it again disables the previous one.
+void ic_set_default_highlighter(ic_highlight_fun_t* highlighter, void* arg);
+
+/// Set the style of characters starting at position `pos`.
+void ic_highlight(ic_highlight_env_t* henv, long pos, long count, const char* style );
+
+/// Experimental: Convenience callback for a function that highlights `s` using bbcode's.
+/// The returned string should be allocated and is free'd by the caller.
+typedef char* (ic_highlight_format_fun_t)(const char* s, void* arg);
+
+/// Experimental: Convenience function for highlighting with bbcodes.
+/// Can be called in a `ic_highlight_fun_t` callback to colorize the `input` using the 
+/// the provided `formatted` input that is the styled `input` with bbcodes. The 
+/// content of `formatted` without bbcode tags should match `input` exactly.
+void ic_highlight_formatted(ic_highlight_env_t* henv, const char* input, const char* formatted);
+
+/// \}
+
+//--------------------------------------------------------------
+// Readline with a specific completer and highlighter
+//--------------------------------------------------------------
+
+/// \defgroup readline
+/// \{
+
+/// Read input from the user using rich editing abilities, 
+/// using a particular completion function and highlighter for this call only.
+/// both can be NULL in which case the defaults are used.
+/// @see ic_readline(), ic_set_prompt_marker(), ic_set_default_completer(), ic_set_default_highlighter().
+char* ic_readline_ex(const char* prompt_text, ic_completer_fun_t* completer, void* completer_arg,
+                                              ic_highlight_fun_t* highlighter, void* highlighter_arg);
+
+/// \}
+
+
+//--------------------------------------------------------------
+// Options
+//--------------------------------------------------------------
+
+/// \defgroup options Options
+/// \{
+
+/// Set a prompt marker and a potential marker for extra lines with multiline input. 
+/// Pass \a NULL for the `prompt_marker` for the default marker (`"> "`).
+/// Pass \a NULL for continuation prompt marker to make it equal to the `prompt_marker`.
+void ic_set_prompt_marker( const char* prompt_marker, const char* continuation_prompt_marker );
+
+/// Get the current prompt marker.
+const char* ic_get_prompt_marker(void);
+
+/// Get the current continuation prompt marker.
+const char* ic_get_continuation_prompt_marker(void);
+
+/// Disable or enable multi-line input (enabled by default).
+/// Returns the previous setting.
+bool ic_enable_multiline( bool enable );
+
+/// Disable or enable sound (enabled by default).
+/// A beep is used when tab cannot find any completion for example.
+/// Returns the previous setting.
+bool ic_enable_beep( bool enable );
+
+/// Disable or enable color output (enabled by default).
+/// Returns the previous setting.
+bool ic_enable_color( bool enable );
+
+/// Disable or enable duplicate entries in the history (disabled by default).
+/// Returns the previous setting.
+bool ic_enable_history_duplicates( bool enable );
+
+/// Disable or enable automatic tab completion after a completion 
+/// to expand as far as possible if the completions are unique. (disabled by default).
+/// Returns the previous setting.
+bool ic_enable_auto_tab( bool enable );
+
+/// Disable or enable preview of a completion selection (enabled by default)
+/// Returns the previous setting.
+bool ic_enable_completion_preview( bool enable );
+
+/// Disable or enable automatic identation of continuation lines in multiline
+/// input so it aligns with the initial prompt.
+/// Returns the previous setting.
+bool ic_enable_multiline_indent(bool enable);
+
+/// Disable or enable display of short help messages for history search etc.
+/// (full help is always dispayed when pressing F1 regardless of this setting)
+/// @returns the previous setting.
+bool ic_enable_inline_help(bool enable);
+
+/// Disable or enable hinting (enabled by default)
+/// Shows a hint inline when there is a single possible completion.
+/// @returns the previous setting.
+bool ic_enable_hint(bool enable);
+
+/// Set millisecond delay before a hint is displayed. Can be zero. (500ms by default).
+long ic_set_hint_delay(long delay_ms);
+
+/// Disable or enable syntax highlighting (enabled by default).
+/// This applies regardless whether a syntax highlighter callback was set (`ic_set_highlighter`)
+/// Returns the previous setting.
+bool ic_enable_highlight(bool enable);
+
+
+/// Set millisecond delay for reading escape sequences in order to distinguish
+/// a lone ESC from the start of a escape sequence. The defaults are 100ms and 10ms, 
+/// but it may be increased if working with very slow terminals.
+void ic_set_tty_esc_delay(long initial_delay_ms, long followup_delay_ms);
+
+/// Enable highlighting of matching braces (and error highlight unmatched braces).`
+bool ic_enable_brace_matching(bool enable);
+
+/// Set matching brace pairs.
+/// Pass \a NULL for the default `"()[]{}"`.
+void ic_set_matching_braces(const char* brace_pairs);
+
+/// Enable automatic brace insertion (enabled by default).
+bool ic_enable_brace_insertion(bool enable);
+
+/// Set matching brace pairs for automatic insertion.
+/// Pass \a NULL for the default `()[]{}\"\"''`
+void ic_set_insertion_braces(const char* brace_pairs);
+
+/// \}
+
+
+//--------------------------------------------------------------
+// Advanced Completion
+//--------------------------------------------------------------
+
+/// \defgroup completex Advanced Completion
+/// \{
+
+/// Get the raw current input (and cursor position if `cursor` != NULL) for the completion.
+/// Usually completer functions should look at their `prefix` though as transformers
+/// like `ic_complete_word` may modify the prefix (for example, unescape it).
+const char* ic_completion_input( ic_completion_env_t* cenv, long* cursor );
+
+/// Get the completion argument passed to `ic_set_completer`.
+void* ic_completion_arg( const ic_completion_env_t* cenv );
+
+/// Do we have already some completions?
+bool ic_has_completions( const ic_completion_env_t* cenv );
+
+/// Do we already have enough completions and should we return if possible? (for improved latency)
+bool ic_stop_completing( const ic_completion_env_t* cenv);
+
+
+/// Primitive completion, cannot be used with most transformers (like `ic_complete_word` and `ic_complete_qword`).
+/// When completed, `delete_before` _bytes_ are deleted before the cursor position,
+/// `delete_after` _bytes_ are deleted after the cursor, and finally `completion` is inserted.
+/// The `display` is used to display the completion in the completion menu, and `help` is displayed
+/// with hinting. Both `display` and `help` can be NULL.
+/// (all are copied by isocline and do not need to be preserved or allocated).
+///
+/// Returns `true` if the callback should continue trying to find more possible completions.
+/// If `false` is returned, the callback should try to return and not add more completions (for improved latency).
+bool ic_add_completion_prim( ic_completion_env_t* cenv, const char* completion, 
+                              const char* display, const char* help, 
+                               long delete_before, long delete_after);
+
+/// \}
+
+//--------------------------------------------------------------
+/// \defgroup helper Character Classes.
+/// Convenience functions for character classes, highlighting and completion.
+/// \{
+
+/// Convenience: return the position of a previous code point in a UTF-8 string `s` from postion `pos`.
+/// Returns `-1` if `pos <= 0` or `pos > strlen(s)` (or other errors).
+long ic_prev_char( const char* s, long pos );
+
+/// Convenience: return the position of the next code point in a UTF-8 string `s` from postion `pos`.
+/// Returns `-1` if `pos < 0` or `pos >= strlen(s)` (or other errors).
+long ic_next_char( const char* s, long pos );
+
+/// Convenience: does a string `s` starts with a given `prefix` ?
+bool ic_starts_with( const char* s, const char* prefix );
+
+/// Convenience: does a string `s` starts with a given `prefix` ignoring (ascii) case?
+bool ic_istarts_with( const char* s, const char* prefix );
+
+
+/// Convenience: character class for whitespace `[ \t\r\n]`.
+bool ic_char_is_white(const char* s, long len);
+
+/// Convenience: character class for non-whitespace `[^ \t\r\n]`.
+bool ic_char_is_nonwhite(const char* s, long len);
+
+/// Convenience: character class for separators.
+/// (``[ \t\r\n,.;:/\\(){}\[\]]``.)
+/// This is used for word boundaries in isocline.
+bool ic_char_is_separator(const char* s, long len);
+
+/// Convenience: character class for non-separators.
+bool ic_char_is_nonseparator(const char* s, long len);
+
+/// Convenience: character class for letters (`[A-Za-z]` and any unicode > 0x80).
+bool ic_char_is_letter(const char* s, long len);
+
+/// Convenience: character class for digits (`[0-9]`).
+bool ic_char_is_digit(const char* s, long len);
+
+/// Convenience: character class for hexadecimal digits (`[A-Fa-f0-9]`).
+bool ic_char_is_hexdigit(const char* s, long len);
+
+/// Convenience: character class for identifier letters (`[A-Za-z0-9_-]` and any unicode > 0x80).
+bool ic_char_is_idletter(const char* s, long len);
+
+/// Convenience: character class for filename letters (_not in_ " \t\r\n`@$><=;|&\{\}\(\)\[\]]").
+bool ic_char_is_filename_letter(const char* s, long len);
+
+
+/// Convenience: If this is a token start, return the length. Otherwise return 0.
+long ic_is_token(const char* s, long pos, ic_is_char_class_fun_t* is_token_char);
+
+/// Convenience: Does this match the specified token? 
+/// Ensures not to match prefixes or suffixes, and returns the length of the match (in bytes).
+/// E.g. `ic_match_token("function",0,&ic_char_is_letter,"fun")` returns 0.
+/// while `ic_match_token("fun x",0,&ic_char_is_letter,"fun"})` returns 3.
+long ic_match_token(const char* s, long pos, ic_is_char_class_fun_t* is_token_char, const char* token);
+
+
+/// Convenience: Do any of the specified tokens match? 
+/// Ensures not to match prefixes or suffixes, and returns the length of the match (in bytes).
+/// E.g. `ic_match_any_token("function",0,&ic_char_is_letter,{"fun","func",NULL})` returns 0.
+/// while `ic_match_any_token("func x",0,&ic_char_is_letter,{"fun","func",NULL})` returns 4.
+long ic_match_any_token(const char* s, long pos, ic_is_char_class_fun_t* is_token_char, const char** tokens);
+
+/// \}
+
+//--------------------------------------------------------------
+/// \defgroup term Terminal
+///
+/// Experimental: Low level terminal output.
+/// Ensures basic ANSI SGR escape sequences are processed 
+/// in a portable way (e.g. on Windows)
+/// \{
+
+/// Initialize for terminal output.
+/// Call this before using the terminal write functions (`ic_term_write`)
+/// Does nothing on most platforms but on Windows it sets the console to UTF8 output and possible 
+/// enables virtual terminal processing.
+void ic_term_init(void);
+
+/// Call this when done with the terminal functions.
+void ic_term_done(void);
+
+/// Flush the terminal output. 
+/// (happens automatically on newline characters ('\n') as well).
+void ic_term_flush(void);
+
+/// Write a string to the console (and process CSI escape sequences).
+void ic_term_write(const char* s);
+
+/// Write a string to the console and end with a newline 
+/// (and process CSI escape sequences).
+void ic_term_writeln(const char* s);
+
+/// Write a formatted string to the console.
+/// (and process CSI escape sequences)
+void ic_term_writef(const char* fmt, ...);
+
+/// Write a formatted string to the console.
+void ic_term_vwritef(const char* fmt, va_list args);
+
+/// Set text attributes from a style.
+void ic_term_style( const char* style );
+
+/// Set text attribute to bold.
+void ic_term_bold(bool enable);
+
+/// Set text attribute to underline.
+void ic_term_underline(bool enable);
+
+/// Set text attribute to italic.
+void ic_term_italic(bool enable);
+
+/// Set text attribute to reverse video.
+void ic_term_reverse(bool enable);
+
+/// Set text attribute to ansi color palette index between 0 and 255 (or 256 for the ANSI "default" color).
+/// (auto matched to smaller palette if not supported)
+void ic_term_color_ansi(bool foreground, int color);
+
+/// Set text attribute to 24-bit RGB color (between `0x000000` and `0xFFFFFF`).
+/// (auto matched to smaller palette if not supported)
+void ic_term_color_rgb(bool foreground, uint32_t color );
+
+/// Reset the text attributes.
+void ic_term_reset( void );
+
+/// Get the palette used by the terminal:
+/// This is usually initialized from the COLORTERM environment variable. The 
+/// possible values of COLORTERM for each palette are given in parenthesis.
+///
+/// - 1: monochrome (`monochrome`)
+/// - 3: old ANSI terminal with 8 colors, using bold for bright (`8color`/`3bit`)
+/// - 4: regular ANSI terminal with 16 colors.     (`16color`/`4bit`)
+/// - 8: terminal with ANSI 256 color palette.     (`256color`/`8bit`)
+/// - 24: true-color terminal with full RGB colors. (`truecolor`/`24bit`/`direct`)
+int ic_term_get_color_bits( void );
+
+/// \}
+
+//--------------------------------------------------------------
+/// \defgroup async ASync
+/// Async support
+/// \{
+
+/// Thread-safe way to asynchronously unblock a readline.
+/// Behaves as if the user pressed the `ctrl-C` character
+/// (resulting in returning NULL from `ic_readline`).
+/// Returns `true` if the event was successfully delivered.
+/// (This may not be supported on all platforms, but it is
+/// functional on Linux, macOS and Windows).
+bool ic_async_stop(void);
+
+/// \}
+
+//--------------------------------------------------------------
+/// \defgroup alloc Custom Allocation
+/// Register allocation functions for custom allocators
+/// \{
+
+typedef void* (ic_malloc_fun_t)( size_t size );
+typedef void* (ic_realloc_fun_t)( void* p, size_t newsize );
+typedef void  (ic_free_fun_t)( void* p );
+
+/// Initialize with custom allocation functions.
+/// This must be called as the first function in a program!
+void ic_init_custom_alloc( ic_malloc_fun_t* _malloc, ic_realloc_fun_t* _realloc, ic_free_fun_t* _free );
+
+/// Free a potentially custom alloc'd pointer (in particular, the result returned from `ic_readline`)
+void ic_free( void* p );
+
+/// Allocate using the current memory allocator.
+void* ic_malloc(size_t sz);
+
+/// Duplicate a string using the current memory allocator.
+const char* ic_strdup( const char* s );
+
+/// \}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /// IC_ISOCLINE_H

extern/isocline/readme.md

@@ -0,0 +1,460 @@
+<!-- <img align="right" width="350px" src="doc/completion-macos.png"/> -->
+
+<img align="left" src="doc/isocline-inline.svg"/>
+
+# Isocline: a portable readline alternative.
+ 
+Isocline is a pure C library that can be used as an alternative to the GNU readline library (latest release v1.0.9, 2022-01-15).
+
+- Small: less than 8k lines and can be compiled as a single C file without 
+  any dependencies or configuration (e.g. `gcc -c src/isocline.c`).
+  
+- Portable: works on Unix, Windows, and macOS, and uses a minimal
+  subset of ANSI escape sequences.
+    
+- Features: extensive multi-line editing mode (`shift-tab`), (24-bit) color, history, completion, unicode, 
+  undo/redo, incremental history search, inline hints, syntax highlighting, brace matching,
+  closing brace insertion, auto indentation, graceful fallback, support for custom allocators, etc.
+  
+- License: MIT. 
+
+- Comes with a Haskell binding ([`System.Console.Isocline`][hdoc].
+
+Enjoy,
+  Daan
+  
+<!--  <img align="right" width="350px" src="doc/history-win.png"/> -->
+  
+# Demo
+
+![recording](doc/record-macos.svg)  
+
+Shows in order: unicode, syntax highlighting, brace matching, jump to matching brace, auto indent, multiline editing, 24-bit colors, inline hinting, filename completion, and incremental history search.  
+<sub>(screen capture was made with [termtosvg] by Nicolas Bedos)</sub>
+
+# Usage
+
+Include the isocline header in your C or C++ source:
+```C
+#include <include/isocline.h>
+```
+
+and call `ic_readline` to get user input with rich editing abilities:
+```C
+char* input;
+while( (input = ic_readline("prompt")) != NULL ) { // ctrl+d/c or errors return NULL
+  printf("you typed:\n%s\n", input); // use the input
+  free(input);  
+}
+```
+
+See the [example] for a full example with completion, syntax highligting, history, etc.
+
+# Run the Example
+
+You can compile and run the [example] as:
+```
+$ gcc -o example -Iinclude test/example.c src/isocline.c
+$ ./example
+```
+
+or, the Haskell [example][HaskellExample]:
+```
+$ ghc -ihaskell test/Example.hs src/isocline.c
+$ ./test/Example
+```
+
+
+# Editing with Isocline
+
+Isocline tries to be as compatible as possible with standard [GNU Readline] key bindings.
+
+### Overview:
+```apl
+       home/ctrl-a       cursor     end/ctrl-e
+         ┌─────────────────┼───────────────┐    (navigate)
+         │     ctrl-left   │  ctrl-right   │
+         │         ┌───────┼──────┐        │    ctrl-r   : search history
+         ▼         ▼       ▼      ▼        ▼    tab      : complete word
+  prompt> it is the quintessential language     shift-tab: insert new line
+         ▲         ▲              ▲        ▲    esc      : delete input, done
+         │         └──────────────┘        │    ctrl-z   : undo
+         │    alt-backsp        alt-d      │
+         └─────────────────────────────────┘    (delete)
+       ctrl-u                          ctrl-k
+```
+
+<sub>Note: on macOS, the meta (alt) key is not directly available in most terminals. 
+Terminal/iTerm2 users can activate the meta key through
+`Terminal` &rarr; `Preferences` &rarr; `Settings` &rarr; `Use option as meta key`.</sub>
+
+### Key Bindings
+
+These are also shown when pressing `F1` on a Isocline prompt. We use `^` as a shorthand for `ctrl-`:
+
+| Navigation        |                                                 |
+|-------------------|-------------------------------------------------|
+| `left`,`^b`       | go one character to the left |
+| `right`,`^f   `   | go one character to the right |
+| `up           `   | go one row up, or back in the history |
+| `down         `   | go one row down, or forward in the history |
+| `^left        `   | go to the start of the previous word |
+| `^right       `   | go to the end the current word |
+| `home`,`^a    `   | go to the start of the current line |
+| `end`,`^e     `   | go to the end of the current line |
+| `pgup`,`^home `   | go to the start of the current input |
+| `pgdn`,`^end  `   | go to the end of the current input |
+| `alt-m        `   | jump to matching brace |
+| `^p           `   | go back in the history |
+| `^n           `   | go forward in the history |
+| `^r`,`^s      `   | search the history starting with the current word |
+  
+
+| Deletion        |                                                 |
+|-------------------|-------------------------------------------------|
+| `del`,`^d     `   | delete the current character |
+| `backsp`,`^h  `   | delete the previous character |
+| `^w           `   | delete to preceding white space |
+| `alt-backsp   `   | delete to the start of the current word |
+| `alt-d        `   | delete to the end of the current word |
+| `^u           `   | delete to the start of the current line |
+| `^k           `   | delete to the end of the current line |
+| `esc          `   | delete the current input, or done with empty input |
+  
+
+| Editing           |                                                 |
+|-------------------|-------------------------------------------------|
+| `enter        `   | accept current input |
+| `^enter`,`^j`,`shift-tab` | create a new line for multi-line input |
+| `^l           `   | clear screen |
+| `^t           `   | swap with previous character (move character backward) |
+| `^z`,`^_      `   | undo |
+| `^y           `   | redo |
+| `tab          `   | try to complete the current input |
+  
+
+| Completion menu   |                                                 |
+|-------------------|-------------------------------------------------|
+| `enter`,`left`    | use the currently selected completion |
+| `1` - `9`         | use completion N from the menu |
+| `tab, down    `   | select the next completion |
+| `shift-tab, up`   | select the previous completion |
+| `esc          `   | exit menu without completing |
+| `pgdn`,`^enter`,`^j`   | show all further possible completions |
+  
+
+| Incremental history search        |                                                 |
+|-------------------|-------------------------------------------------|
+| `enter        `   | use the currently found history entry |
+| `backsp`,`^z  `   | go back to the previous match (undo) |
+| `tab`,`^r`,`up`   | find the next match |
+| `shift-tab`,`^s`,`down`  | find an earlier match |
+| `esc          `   | exit search |
+
+
+# Build the Library
+
+### Build as a Single Source
+
+Copy the sources (in `include` and `src`) into your project, or add the library as a [submodule]:
+```
+$ git submodule add https://github.com/daanx/isocline
+```
+and add `isocline/src/isocline.c` to your build rules -- no configuration is needed. 
+
+### Build with CMake
+
+Clone the repository and run cmake to build a static library (`.a`/`.lib`):
+```
+$ git clone https://github.com/daanx/isocline
+$ cd isocline
+$ mkdir -p build/release
+$ cd build/release
+$ cmake ../..
+$ cmake --build .
+```
+This builds a static library `libisocline.a` (or `isocline.lib` on Windows)
+and the example program:
+```
+$ ./example
+```
+
+### Build the Haskell Library
+
+See the Haskell [readme][Haskell] for instructions to build and use the Haskell library.
+
+
+# API Reference
+
+* See the [C API reference][docapi] and the [example] for example usage of history, completion, etc.
+
+* See the [Haskell API reference][hdoc] on Hackage and the Haskell [example][HaskellExample].
+
+
+# Motivation
+
+Isocline was created for use in the [Koka] interactive compiler. 
+This required: pure C (no dependency on a C++ runtime or other libraries), 
+portable (across Linux, macOS, and Windows), unicode support, 
+a BSD-style license, and good functionality for completion and multi-line editing.
+
+Some other excellent libraries that we considered:
+[GNU readline],
+[editline](https://github.com/troglobit/editline),
+[linenoise](https://github.com/antirez/linenoise),
+[replxx](https://github.com/AmokHuginnsson/replxx), and 
+[Haskeline](https://github.com/judah/haskeline).
+
+
+# Formatted Output
+
+Isocline also exposes functions for rich terminal output
+as `ic_print` (and `ic_println` and `ic_printf`). 
+Inspired by the (Python) [Rich][RichBBcode] library, 
+this supports a form of [bbcode]'s to format the output:
+```c
+ic_println( "[b]bold [red]and red[/red][/b]" );
+```
+Each print automatically closes any open tags that were
+not yet closed. Also, you can use a general close
+tag as `[/]` to close the innermost tag, so the
+following print is equivalent to the earlier one:
+```c
+ic_println( "[b]bold [red]and red[/]" );
+```
+There can be multiple styles in one tag
+(where the first name is used for the closing tag):
+```c
+ic_println( "[u #FFD700]underlined gold[/]" );
+```
+
+Sometimes, you need to display arbitrary messages
+that may contain sequences that you would not like
+to be interpreted as bbcode tags. One way to do
+this is the `[!`_tag_`]` which ignores formatting
+up to a close tag of the form `[/`_tag_`]`.
+```c
+ic_printf( "[red]red? [!pre]%s[/pre].\n", "[blue]not blue!" );
+```
+
+Predefined styles include `b` (bold),
+`u` (underline), `i` (italic), and `r` (reverse video), but
+you can (re)define any style yourself as:
+```c
+ic_style_def("warning", "crimson u");
+```
+
+and use them like any builtin style or property:
+```c
+ic_println( "[warning]this is a warning![/]" );
+```
+which is great for adding themes to your application.
+
+Each `ic_print` function always closes any unclosed tags automatically.
+To open a style persistently, use `ic_style_open` with a matching
+`ic_style_close` which scopes over any `ic_print` statements in between.
+```c
+ic_style_open("warning");
+ic_println("[b]crimson underlined and bold[/]");
+ic_style_close();
+```
+
+# Advanced
+
+
+## BBCode Format
+
+An open tag can have multiple white space separated
+entries that are
+either a _style name_, or a primitive _property_[`=`_value_].
+
+### Styles
+
+Isocline provides the following builtin styles as property shorthands:
+`b` (bold), `u` (underline), `i` (italic), `r` (reverse video),
+and some builtin styles for syntax highlighting:
+`keyword`, `control` (control-flow keywords), `string`,
+`comment`, `number`, `type`, `constant`.
+
+Predefined styles used by Isocline itself are:
+
+- `ic-prompt`: prompt style, e.g. `ic_style_def("ic-prompt", "yellow on blue")`.
+- `ic-info`: information (like the numbers in a completion menu).    
+- `ic-diminish`: dim text (used for example in history search).
+- `ic-emphasis`: emphasized text (also used in history search).
+- `ic-hint`: color of an inline hint.
+- `ic-error`: error color (like an unmatched brace).   
+- `ic-bracematch`: color of matching parenthesis.
+
+### Properties
+
+Boolean properties are by default `on`:
+
+- `bold` [`=`(`on`|`off`)]
+- `italic` [`=`(`on`|`off`)]
+- `underline` [`=`(`on`|`off`)]
+- `reverse` [`=`(`on`|`off`)]
+
+Color properties can be assigned a _color_:
+
+- `color=`_color_
+- `bgcolor=`_color_
+- _color_: equivalent to `color=`_color_.
+- `on` _color_: equivalent to `bgcolor=`_color_.
+
+A color value can be specified in many ways:
+
+- any standard HTML [color name][htmlcolors].
+- any of the 16 standard ANSI [color names][ansicolors] by prefixing `ansi-` 
+  (like `ansi-black` or `ansi-maroon`).   
+  The actual color value of these depend on the a terminal theme.
+- `#`_rrggbb_ or `#`_rgb_ for a specific 24-bit color.
+- `ansi-color=`_idx_: where 0 <= _idx_ <= 256 specifies an entry in the
+  standard ANSI 256 [color palette][ansicolor256], where 256 is used for the ANSI 
+  default color.
+
+
+## Environment Variables
+
+- `NO_COLOR`: if present no colors are displayed.
+- `CLICOLOR=1`: if set, the `LSCOLORS` or `LS_COLORS` environment variables are used to colorize
+  filename completions.
+- `COLORTERM=`(`truecolor`|`256color`|`16color`|`8color`|`monochrome`): enable a certain color palette, see the next section.
+- `TERM`: used on some systems to determine the color
+
+## Colors
+
+Isocline supports 24-bit colors and any RGB colors are automatically
+mapped to a reduced palette on older terminals if these do not
+support true color. Detection of full color support
+is not always possible to do automatically and you can
+set the `COLORTERM` environment variable expicitly to force Isocline to use
+a specific palette:
+- `COLORTERM=truecolor`: use 24-bit colors.  
+  <img width="500px" src="doc/color/ansi-truecolor.png"/>
+- `COLORTERM=256color`: use the ANSI 256 color palette.  
+  <img width="500px" src="doc/color/ansi-256color.png"/>
+- `COLORTERM=16color` : use the regular ANSI 16 color 
+   palette (8 normal and 8 bright colors).  
+   <img width="500px" src="doc/color/ansi-16color.png"/>
+- `COLORTERM=8color`: use bold for bright colors.
+- `COLORTERM=monochrome`: use no color.
+
+The above screenshots are made with the 
+[`test_colors.c`](https://github.com/daanx/isocline/blob/main/test/test_colors.c) program. You can test your own
+terminal as:
+```
+$ gcc -o test_colors -Iinclude test/test_colors.c src/isocline.c
+$ ./test_colors
+$ COLORTERM=truecolor ./test_colors
+$ COLORTERM=16color ./test_colors
+```
+
+## ANSI Escape Sequences
+
+Isocline uses just few ANSI escape sequences that are widely
+supported:
+- `ESC[`_n_`A`, `ESC[`_n_`B`, `ESC[`_n_`C`, and `ESC[`_n_`D`,
+  for moving the cursor _n_ places up, down, right, and left.
+- `ESC[K` to clear the line from the cursor.
+- `ESC[`_n_`m` for colors, with _n_ one of: 0 (reset), 1,22 (bold), 3,23 (italic),
+   4,24 (underline), 7,27 (reverse), 30-37,40-47,90-97,100-107 (color),
+   and 39,49 (select default color).
+- `ESC[38;5;`_n_`m`, `ESC[48;5;`_n_`m`, `ESC[38;2;`_r_`;`_g_`;`_b_`m`, `ESC[48;2;`_r_`;`_g_`;`_b_`m`: 
+  on terminals that support it, select 
+  entry _n_ from the
+  256 color ANSI palette (used with `XTERM=xterm-256color` for example), or directly specify
+  any 24-bit _rgb_ color (used with `COLORTERM=truecolor`) for the foreground or background.
+    
+On Windows the above functionality is implemented using the Windows console API
+(except if running in the new Windows Terminal which supports these escape
+sequences natively).
+
+## Async and Threads
+
+Isocline is _not_ thread-safe and `ic_readline`_xxx_ and `ic_print`_xxx_ should
+be used from one thread only.
+
+The best way to use `ic_readline` asynchronously is
+to run it in a (blocking) dedicated thread and deliver
+results from there to the async event loop. Isocline has the
+```C
+bool ic_async_stop(void)
+```
+function that is thread-safe and can deliver an
+asynchronous event to Isocline that unblocks a current
+`ic_readline` and makes it behave as if the user pressed
+`ctrl-c` (which returns NULL from the read line call).
+
+## Color Mapping
+
+To map full RGB colors to an ANSI 256 or 16-color palette
+Isocline finds a palette color with the minimal "color distance" to
+the original color. There are various
+ways of calculating this: one way is to take the euclidean distance
+in the sRGB space (_simple-rgb_), a slightly better way is to 
+take a weighted distance where the weight distribution is adjusted
+according to how big the red component is ([redmean](https://en.wikipedia.org/wiki/Color_difference),
+denoted as _delta-rgb_ in the figure), 
+this is used by Isocline),
+and finally, we can first translate into a perceptually uniform color space
+(CIElab) and calculate the distance there using the [CIEDE2000](https://en.wikipedia.org/wiki/Color_difference)
+algorithm (_ciede2000_). Here are these three methods compared on
+some colors: 
+
+![color space comparison](doc/color/colorspace-map.png)
+
+Each top row is the true 24-bit RGB color. Surprisingly,
+the sophisticated CIEDE2000 distance seems less good here compared to the 
+simpler methods (as in the upper left block for example)
+(perhaps  because this algorithm was created to find close
+perceptual colors in images where lightness differences may be given
+less weight?). CIEDE2000 also leads to more "outliers", for example as seen
+in column 5. Given these results, Isocline uses _redmean_ for
+color mapping. We also add a gray correction that makes it less
+likely to substitute a color for a gray value (and the other way
+around).
+
+
+## Possible Future Extensions
+
+- Vi key bindings.
+- kill buffer.
+- make the `ic_print`_xxx_ functions thread-safe.
+- extended low-level terminal functions.
+- status and progress bars.
+- prompt variants: confirm, etc.
+- ...
+
+Contact me if you are interested in doing any of these :-)
+
+
+# Releases
+
+* `2022-01-15`: v1.0.9: fix missing `ic_completion_arg` (issue #6), 
+   fix null ptr check in ic_print (issue #7), fix crash when using /dev/null as both input and output.
+* `2021-09-05`: v1.0.5: use our own wcwidth for consistency; 
+  thanks to Hans-Georg Breunig for helping with testing on NetBSD.
+* `2021-08-28`: v1.0.4: fix color query on Ubuntu/Gnome
+* `2021-08-27`: v1.0.3: fix duplicates in completions 
+* `2021-08-23`: v1.0.2: fix windows eol wrapping
+* `2021-08-21`: v1.0.1: fix line-buffering
+* `2021-08-20`: v1.0.0: initial release  
+  
+
+
+[GNU readline]: https://tiswww.case.edu/php/chet/readline/rltop.html
+[koka]: http://www.koka-lang.org
+[submodule]: https://git-scm.com/book/en/v2/Git-Tools-Submodules
+[Haskell]: https://github.com/daanx/isocline/tree/main/haskell
+[HaskellExample]: https://github.com/daanx/isocline/blob/main/test/Example.hs
+[example]: https://github.com/daanx/isocline/blob/main/test/example.c
+[termtosvg]: https://github.com/nbedos/termtosvg
+[Rich]: https://github.com/willmcgugan/rich
+[RichBBcode]: https://rich.readthedocs.io/en/latest/markup.html
+[bbcode]: https://en.wikipedia.org/wiki/BBCode
+[htmlcolors]: https://en.wikipedia.org/wiki/Web_colors#HTML_color_names
+[ansicolors]: https://en.wikipedia.org/wiki/Web_colors#Basic_colors
+[ansicolor256]: https://en.wikipedia.org/wiki/ANSI_escape_code#8-bit
+[docapi]: https://daanx.github.io/isocline
+[hdoc]: https://hackage.haskell.org/package/isocline/docs/System-Console-Isocline.html

extern/isocline/src/attr.c

@@ -0,0 +1,294 @@
+/* ----------------------------------------------------------------------------
+  Copyright (c) 2021, Daan Leijen
+  This is free software; you can redistribute it and/or modify it
+  under the terms of the MIT License. A copy of the license can be
+  found in the "LICENSE" file at the root of this distribution.
+-----------------------------------------------------------------------------*/
+#include <string.h>
+
+#include "common.h"
+#include "stringbuf.h" // str_next_ofs
+#include "attr.h"
+#include "term.h"      // color_from_ansi256
+
+//-------------------------------------------------------------
+// Attributes
+//-------------------------------------------------------------
+
+ic_private attr_t attr_none(void) {
+  attr_t attr;
+  attr.value = 0;
+  return attr;
+}
+
+ic_private attr_t attr_default(void) {
+  attr_t attr = attr_none();
+  attr.x.color = IC_ANSI_DEFAULT;
+  attr.x.bgcolor = IC_ANSI_DEFAULT;
+  attr.x.bold = IC_OFF;
+  attr.x.underline = IC_OFF; 
+  attr.x.reverse = IC_OFF;
+  attr.x.italic = IC_OFF; 
+  return attr;
+}
+
+ic_private bool attr_is_none(attr_t attr) {
+  return (attr.value == 0);
+}
+
+ic_private bool attr_is_eq(attr_t attr1, attr_t attr2) {
+  return (attr1.value == attr2.value);
+}
+
+ic_private attr_t attr_from_color( ic_color_t color ) {
+  attr_t attr = attr_none();
+  attr.x.color = color;
+  return attr;
+}
+
+
+ic_private attr_t attr_update_with( attr_t oldattr, attr_t newattr ) {
+  attr_t attr = oldattr;
+  if (newattr.x.color != IC_COLOR_NONE)   { attr.x.color = newattr.x.color; }
+  if (newattr.x.bgcolor != IC_COLOR_NONE) { attr.x.bgcolor = newattr.x.bgcolor; }
+  if (newattr.x.bold != IC_NONE)          { attr.x.bold = newattr.x.bold; }
+  if (newattr.x.italic != IC_NONE)        { attr.x.italic = newattr.x.italic; }
+  if (newattr.x.reverse != IC_NONE)       { attr.x.reverse = newattr.x.reverse; }
+  if (newattr.x.underline != IC_NONE)     { attr.x.underline = newattr.x.underline; }
+  return attr;
+}
+
+static bool sgr_is_digit(char c) {
+  return (c >= '0' && c <= '9');
+}
+
+static bool sgr_is_sep( char c ) {
+  return (c==';' || c==':');
+}
+
+static bool sgr_next_par(const char* s, ssize_t* pi, ssize_t* par) {
+  const ssize_t i = *pi;
+  ssize_t n = 0;
+  while( sgr_is_digit(s[i+n])) { 
+    n++; 
+  }
+  if (n==0) { 
+    *par = 0;
+    return true;
+  }
+  else {
+    *pi = i+n;
+    return ic_atoz(s+i, par);    
+  }
+}
+
+static bool sgr_next_par3(const char* s, ssize_t* pi, ssize_t* p1, ssize_t* p2, ssize_t* p3) {
+  bool ok = false;
+  ssize_t i = *pi;
+  if (sgr_next_par(s,&i,p1) && sgr_is_sep(s[i])) {
+    i++;
+    if (sgr_next_par(s,&i,p2) && sgr_is_sep(s[i])) {
+      i++;
+      if (sgr_next_par(s,&i,p3)) {
+        ok = true;
+      };
+    }
+  }
+  *pi = i;
+  return ok;
+}
+
+ic_private attr_t attr_from_sgr( const char* s, ssize_t len) {
+  attr_t attr = attr_none();
+  for( ssize_t i = 0; i < len && s[i] != 0; i++) {
+    ssize_t cmd = 0;
+    if (!sgr_next_par(s,&i,&cmd)) continue;
+    switch(cmd) {
+      case  0: attr = attr_default(); break;
+      case  1: attr.x.bold = IC_ON; break;
+      case  3: attr.x.italic = IC_ON; break;
+      case  4: attr.x.underline = IC_ON; break;
+      case  7: attr.x.reverse = IC_ON; break;
+      case 22: attr.x.bold = IC_OFF; break;
+      case 23: attr.x.italic = IC_OFF; break;
+      case 24: attr.x.underline = IC_OFF; break;
+      case 27: attr.x.reverse = IC_OFF; break;
+      case 39: attr.x.color = IC_ANSI_DEFAULT; break;
+      case 49: attr.x.bgcolor = IC_ANSI_DEFAULT; break;
+      default: {
+        if (cmd >= 30 && cmd <= 37) {
+          attr.x.color = IC_ANSI_BLACK + (unsigned)(cmd - 30);
+        }
+        else if (cmd >= 40 && cmd <= 47) {
+          attr.x.bgcolor = IC_ANSI_BLACK + (unsigned)(cmd - 40);
+        }
+        else if (cmd >= 90 && cmd <= 97) {
+          attr.x.color = IC_ANSI_DARKGRAY + (unsigned)(cmd - 90);
+        }
+        else if (cmd >= 100 && cmd <= 107) {
+          attr.x.bgcolor = IC_ANSI_DARKGRAY + (unsigned)(cmd - 100);
+        }
+        else if ((cmd == 38 || cmd == 48) && sgr_is_sep(s[i])) {
+          // non-associative SGR :-(          
+          ssize_t par = 0;
+          i++;
+          if (sgr_next_par(s, &i, &par)) {
+            if (par==5 && sgr_is_sep(s[i])) {
+              // ansi 256 index
+              i++;
+              if (sgr_next_par(s, &i, &par) && par >= 0 && par <= 0xFF) {
+                ic_color_t color = color_from_ansi256(par);
+                if (cmd==38) { attr.x.color = color; }
+                        else { attr.x.bgcolor = color; }
+              }
+            }
+            else if (par == 2 && sgr_is_sep(s[i])) {
+              // rgb value
+              i++;
+              ssize_t r,g,b;
+              if (sgr_next_par3(s, &i, &r,&g,&b)) {
+                ic_color_t color = ic_rgbx(r,g,b);
+                if (cmd==38) { attr.x.color = color; }
+                        else { attr.x.bgcolor = color; }
+              }
+            }
+          }
+        }
+        else {
+          debug_msg("attr: unknow ANSI SGR code: %zd\n", cmd );
+        }
+      }
+    }
+  }
+  return attr;
+}
+
+ic_private attr_t attr_from_esc_sgr( const char* s, ssize_t len) {
+  if (len <= 2 || s[0] != '\x1B' || s[1] != '[' || s[len-1] != 'm') return attr_none();
+  return attr_from_sgr(s+2, len-2);
+}
+
+
+//-------------------------------------------------------------
+// Attribute buffer
+//-------------------------------------------------------------
+struct attrbuf_s {
+  attr_t*  attrs;
+  ssize_t  capacity;
+  ssize_t  count;
+  alloc_t* mem;
+};
+
+static bool attrbuf_ensure_capacity( attrbuf_t* ab, ssize_t needed ) {
+  if (needed <= ab->capacity) return true;
+  ssize_t newcap = (ab->capacity <= 0 ? 240 : (ab->capacity > 1000 ? ab->capacity + 1000 : 2*ab->capacity));
+  if (needed > newcap) { newcap = needed; }
+  attr_t* newattrs = mem_realloc_tp( ab->mem, attr_t, ab->attrs, newcap );
+  if (newattrs == NULL) return false;
+  ab->attrs = newattrs;
+  ab->capacity = newcap;
+  assert(needed <= ab->capacity);
+  return true;
+}
+
+static bool attrbuf_ensure_extra( attrbuf_t* ab, ssize_t extra ) {
+  const ssize_t needed = ab->count + extra;
+  return attrbuf_ensure_capacity( ab, needed );
+}
+
+
+ic_private attrbuf_t* attrbuf_new( alloc_t* mem ) {
+  attrbuf_t* ab = mem_zalloc_tp(mem,attrbuf_t);
+  if (ab == NULL) return NULL;
+  ab->mem = mem;
+  attrbuf_ensure_extra(ab,1);
+  return ab;
+}
+
+ic_private void attrbuf_free( attrbuf_t* ab ) {
+  if (ab==NULL) return;
+  mem_free(ab->mem, ab->attrs);
+  mem_free(ab->mem, ab);
+}
+
+ic_private void attrbuf_clear(attrbuf_t* ab) {
+  if (ab == NULL) return;
+  ab->count = 0;
+}
+
+ic_private ssize_t attrbuf_len( attrbuf_t* ab ) {
+  return (ab==NULL ? 0 : ab->count);
+}
+
+ic_private const attr_t* attrbuf_attrs( attrbuf_t* ab, ssize_t expected_len ) {
+  assert(expected_len <= ab->count );
+  // expand if needed
+  if (ab->count < expected_len) {    
+    if (!attrbuf_ensure_capacity(ab,expected_len)) return NULL;
+    for(ssize_t i = ab->count; i < expected_len; i++) {
+      ab->attrs[i] = attr_none();  
+    }
+    ab->count = expected_len;
+  }
+  return ab->attrs;
+}
+
+
+
+static void attrbuf_update_set_at( attrbuf_t* ab, ssize_t pos, ssize_t count, attr_t attr, bool update ) {
+  const ssize_t end = pos + count;
+  if (!attrbuf_ensure_capacity(ab, end)) return;
+  ssize_t i;
+  // initialize if end is beyond the count (todo: avoid duplicate init and set if update==false?)
+  if (ab->count < end) {
+    for(i = ab->count; i < end; i++) {
+      ab->attrs[i] = attr_none();  
+    }
+    ab->count = end;
+  }
+  // fill pos to end with attr 
+  for(i = pos; i < end; i++) {
+    ab->attrs[i] = (update ? attr_update_with(ab->attrs[i],attr) : attr);    
+  }  
+}
+
+ic_private void attrbuf_set_at( attrbuf_t* ab, ssize_t pos, ssize_t count, attr_t attr ) {
+  attrbuf_update_set_at(ab, pos, count, attr, false);
+}
+
+ic_private void attrbuf_update_at( attrbuf_t* ab, ssize_t pos, ssize_t count, attr_t attr ) {
+  attrbuf_update_set_at(ab, pos, count, attr, true);  
+}
+
+ic_private void attrbuf_insert_at( attrbuf_t* ab, ssize_t pos, ssize_t count, attr_t attr ) {
+  if (pos < 0 || pos > ab->count || count <= 0) return;
+  if (!attrbuf_ensure_extra(ab,count)) return;  
+  ic_memmove( ab->attrs + pos + count, ab->attrs + pos, (ab->count - pos)*ssizeof(attr_t) );
+  ab->count += count;
+  attrbuf_set_at( ab, pos, count, attr );
+}
+
+
+// note: must allow ab == NULL!
+ic_private ssize_t attrbuf_append_n( stringbuf_t* sb, attrbuf_t* ab, const char* s, ssize_t len, attr_t attr ) {
+  if (s == NULL || len == 0) return sbuf_len(sb);
+  if (ab != NULL) {
+    if (!attrbuf_ensure_extra(ab,len)) return sbuf_len(sb);
+    attrbuf_set_at(ab, ab->count, len, attr);
+  }
+  return sbuf_append_n(sb,s,len);
+}
+
+ic_private attr_t attrbuf_attr_at( attrbuf_t* ab, ssize_t pos ) {
+  if (ab==NULL || pos < 0 || pos > ab->count) return attr_none();
+  return ab->attrs[pos];
+}
+
+ic_private void attrbuf_delete_at( attrbuf_t* ab, ssize_t pos, ssize_t count ) {
+  if (ab==NULL || pos < 0 || pos > ab->count) return;
+  if (pos + count > ab->count) { count = ab->count - pos; }
+  if (count == 0) return;
+  assert(pos + count <= ab->count);
+  ic_memmove( ab->attrs + pos, ab->attrs + pos + count, ab->count - (pos + count) );
+  ab->count -= count;
+}

extern/isocline/src/attr.h

@@ -0,0 +1,70 @@
+/* ----------------------------------------------------------------------------
+  Copyright (c) 2021, Daan Leijen
+  This is free software; you can redistribute it and/or modify it
+  under the terms of the MIT License. A copy of the license can be
+  found in the "LICENSE" file at the root of this distribution.
+-----------------------------------------------------------------------------*/
+#pragma once
+#ifndef IC_ATTR_H
+#define IC_ATTR_H
+
+#include "common.h"
+#include "stringbuf.h"
+
+//-------------------------------------------------------------
+// text attributes
+//-------------------------------------------------------------
+
+#define IC_ON   (1)
+#define IC_OFF  (-1)
+#define IC_NONE (0)
+
+// try to fit in 64 bits 
+// note: order is important for some compilers
+// note: each color can actually be 25 bits
+typedef union attr_s {
+  struct {
+    unsigned int  color:28;
+    signed int    bold:2;
+    signed int    reverse:2;
+    unsigned int  bgcolor:28;
+    signed int    underline:2;
+    signed int    italic:2;
+  } x;
+  uint64_t        value;
+} attr_t;
+
+ic_private attr_t attr_none(void);
+ic_private attr_t attr_default(void);
+ic_private attr_t attr_from_color( ic_color_t color );
+
+ic_private bool attr_is_none(attr_t attr);
+ic_private bool attr_is_eq(attr_t attr1, attr_t attr2);
+
+ic_private attr_t attr_update_with( attr_t attr, attr_t newattr );
+
+ic_private attr_t attr_from_sgr( const char* s, ssize_t len);
+ic_private attr_t attr_from_esc_sgr( const char* s, ssize_t len);
+
+//-------------------------------------------------------------
+// attribute buffer used for rich rendering
+//-------------------------------------------------------------
+
+struct attrbuf_s;
+typedef struct attrbuf_s attrbuf_t;
+
+ic_private attrbuf_t*     attrbuf_new( alloc_t* mem );
+ic_private void           attrbuf_free( attrbuf_t* ab );  // ab can be NULL
+ic_private void           attrbuf_clear( attrbuf_t* ab ); // ab can be NULL
+ic_private ssize_t        attrbuf_len( attrbuf_t* ab);    // ab can be NULL
+ic_private const attr_t*  attrbuf_attrs( attrbuf_t* ab, ssize_t expected_len );
+ic_private ssize_t        attrbuf_append_n( stringbuf_t* sb, attrbuf_t* ab, const char* s, ssize_t len, attr_t attr );
+
+ic_private void           attrbuf_set_at( attrbuf_t* ab, ssize_t pos, ssize_t count, attr_t attr );
+ic_private void           attrbuf_update_at( attrbuf_t* ab, ssize_t pos, ssize_t count, attr_t attr );
+ic_private void           attrbuf_insert_at( attrbuf_t* ab, ssize_t pos, ssize_t count, attr_t attr );
+
+ic_private attr_t         attrbuf_attr_at( attrbuf_t* ab, ssize_t pos );   
+ic_private void           attrbuf_delete_at( attrbuf_t* ab, ssize_t pos, ssize_t count );
+
+#endif // IC_ATTR_H

extern/isocline/src/bbcode.c

@@ -0,0 +1,842 @@
+/* ----------------------------------------------------------------------------
+  Copyright (c) 2021, Daan Leijen
+  This is free software; you can redistribute it and/or modify it
+  under the terms of the MIT License. A copy of the license can be
+  found in the "LICENSE" file at the root of this distribution.
+-----------------------------------------------------------------------------*/
+#include <string.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <stdlib.h>  
+
+#include "common.h"
+#include "attr.h"
+#include "term.h"
+#include "bbcode.h" 
+
+//-------------------------------------------------------------
+// HTML color table
+//-------------------------------------------------------------
+
+#include "bbcode_colors.c"
+
+//-------------------------------------------------------------
+// Types
+//-------------------------------------------------------------
+
+typedef struct style_s {
+  const char*  name;  // name of the style
+  attr_t  attr;  // attribute to apply
+} style_t;
+
+typedef enum align_e {
+  IC_ALIGN_LEFT,
+  IC_ALIGN_CENTER,
+  IC_ALIGN_RIGHT
+} align_t;
+
+typedef struct width_s {
+  ssize_t w;     // > 0
+  align_t align;
+  bool    dots;  // "..."  (e.g. "sentence...")
+  char    fill;  // " "    (e.g. "hello      ")
+} width_t;
+
+typedef struct tag_s {  
+  const char* name;   // tag open name
+  attr_t  attr;       // the saved attribute before applying the style
+  width_t width;      // start sequence of at most "width" columns
+  ssize_t pos;        // start position in the output (used for width restriction)
+} tag_t;
+
+
+static void tag_init(tag_t* tag) {
+  memset(tag,0,sizeof(*tag));  
+}
+
+struct bbcode_s {
+  tag_t*       tags;              // stack of tags; one entry for each open tag
+  ssize_t      tags_capacity;
+  ssize_t      tags_nesting;   
+  style_t*     styles;            // list of used defined styles
+  ssize_t      styles_capacity;
+  ssize_t      styles_count;
+  term_t*      term;              // terminal
+  alloc_t*     mem;               // allocator
+  // caches
+  stringbuf_t*  out;              // print buffer
+  attrbuf_t*    out_attrs;
+  stringbuf_t*  vout;             // vprintf buffer 
+};
+
+
+//-------------------------------------------------------------
+// Create, helpers
+//-------------------------------------------------------------
+
+ic_private bbcode_t* bbcode_new( alloc_t* mem, term_t* term ) {
+  bbcode_t* bb = mem_zalloc_tp(mem,bbcode_t);
+  if (bb==NULL) return NULL;
+  bb->mem = mem;
+  bb->term = term;
+  bb->out = sbuf_new(mem);
+  bb->out_attrs = attrbuf_new(mem);
+  bb->vout = sbuf_new(mem);
+  return bb;
+}
+
+ic_private void bbcode_free( bbcode_t* bb ) {
+  for(ssize_t i = 0; i < bb->styles_count; i++) {
+    mem_free(bb->mem, bb->styles[i].name);
+  }
+  mem_free(bb->mem, bb->tags);
+  mem_free(bb->mem, bb->styles);
+  sbuf_free(bb->vout);
+  sbuf_free(bb->out);
+  attrbuf_free(bb->out_attrs);
+  mem_free(bb->mem, bb);
+}
+
+ic_private void bbcode_style_add( bbcode_t* bb, const char* style_name, attr_t attr ) {
+  if (bb->styles_count >= bb->styles_capacity) {
+    ssize_t newlen = bb->styles_capacity + 32;
+    style_t* p = mem_realloc_tp( bb->mem, style_t, bb->styles, newlen );
+    if (p == NULL) return;
+    bb->styles = p;
+    bb->styles_capacity = newlen;
+  }
+  assert(bb->styles_count < bb->styles_capacity);
+  bb->styles[bb->styles_count].name = mem_strdup( bb->mem, style_name );
+  bb->styles[bb->styles_count].attr = attr;
+  bb->styles_count++;
+}
+
+static ssize_t bbcode_tag_push( bbcode_t* bb, const tag_t* tag ) {
+  if (bb->tags_nesting >= bb->tags_capacity) {
+    ssize_t newcap = bb->tags_capacity + 32;
+    tag_t* p = mem_realloc_tp( bb->mem, tag_t, bb->tags, newcap );
+    if (p == NULL) return -1;
+    bb->tags = p;
+    bb->tags_capacity = newcap;    
+  }
+  assert(bb->tags_nesting < bb->tags_capacity);
+  bb->tags[bb->tags_nesting] = *tag;
+  bb->tags_nesting++;
+  return (bb->tags_nesting-1);
+}
+
+static void bbcode_tag_pop( bbcode_t* bb, tag_t* tag ) {
+  if (bb->tags_nesting <= 0) {
+    if (tag != NULL) { tag_init(tag); }
+  }
+  else {
+    bb->tags_nesting--;
+    if (tag != NULL) {
+      *tag = bb->tags[bb->tags_nesting];
+    }    
+  }
+}
+
+//-------------------------------------------------------------
+// Invalid parse/values/balance
+//-------------------------------------------------------------
+
+static void bbcode_invalid(const char* fmt, ... ) {
+  if (getenv("ISOCLINE_BBCODE_DEBUG") != NULL) {
+    va_list args;
+    va_start(args,fmt);
+    vfprintf(stderr,fmt,args);
+    va_end(args);
+  }
+}
+
+//-------------------------------------------------------------
+// Set attributes
+//-------------------------------------------------------------
+
+
+static attr_t bbcode_open( bbcode_t* bb, ssize_t out_pos, const tag_t* tag, attr_t current ) { 
+  // save current and set
+  tag_t cur;
+  tag_init(&cur);
+  cur.name  = tag->name;
+  cur.attr  = current;  
+  cur.width = tag->width;
+  cur.pos   = out_pos;
+  bbcode_tag_push(bb,&cur);
+  return attr_update_with( current, tag->attr );
+}
+
+static bool bbcode_close( bbcode_t* bb, ssize_t base, const char* name, tag_t* pprev ) {
+  // pop until match
+  while (bb->tags_nesting > base) {
+    tag_t prev;
+    bbcode_tag_pop(bb,&prev);
+    if (name==NULL || prev.name==NULL || ic_stricmp(prev.name,name) == 0) {
+      // matched
+      if (pprev != NULL) { *pprev = prev; }
+      return true;
+    }
+    else {
+      // unbalanced: we either continue popping or restore the tags depending if there is a matching open tag in our tags.
+      bool has_open_tag = false;
+      if (name != NULL) {
+        for( ssize_t i = bb->tags_nesting - 1; i > base; i--) {
+          if (bb->tags[i].name != NULL && ic_stricmp(bb->tags[i].name, name) == 0) {
+            has_open_tag = true;
+            break;
+          }
+        }
+      }
+      bbcode_invalid("bbcode: unbalanced tags: open [%s], close [/%s]\n", prev.name, name);            
+      if (!has_open_tag) {
+        bbcode_tag_push( bb, &prev ); // restore the tags and ignore this close tag
+        break;
+      }
+      else {
+        // continue until we hit our open tag
+      }
+    }
+  }
+  if (pprev != NULL) { memset(pprev,0,sizeof(*pprev)); }
+  return false;
+}
+
+//-------------------------------------------------------------
+// Update attributes
+//-------------------------------------------------------------
+
+static const char* attr_update_bool( const char* fname, signed int* field, const char* value ) {
+  if (value == NULL || value[0] == 0 || strcmp(value,"on") || strcmp(value,"true") || strcmp(value,"1")) {
+    *field = IC_ON;
+  }
+  else if (strcmp(value,"off") || strcmp(value,"false") || strcmp(value,"0")) {
+    *field = IC_OFF;
+  }
+  else {
+    bbcode_invalid("bbcode: invalid %s value: %s\n", fname, value );
+  }
+  return fname;
+}
+
+static const char* attr_update_color( const char* fname, ic_color_t* field, const char* value ) {
+  if (value == NULL || value[0] == 0 || strcmp(value,"none") == 0) {
+    *field = IC_COLOR_NONE;
+    return fname;
+  }
+  
+  // hex value
+  if (value[0] == '#') {
+    uint32_t rgb = 0;
+    if (sscanf(value,"#%x",&rgb) == 1) {
+      *field = ic_rgb(rgb);
+    } 
+    else {
+      bbcode_invalid("bbcode: invalid color code: %s\n", value);
+    }
+    return fname;
+  }
+
+  // search color names
+  ssize_t lo = 0;
+  ssize_t hi = IC_HTML_COLOR_COUNT-1;
+  while( lo <= hi ) {
+    ssize_t mid = (lo + hi) / 2;
+    style_color_t* info = &html_colors[mid];
+    int cmp = strcmp(info->name,value);
+    if (cmp < 0) {
+      lo = mid+1;
+    }
+    else if (cmp > 0) {
+      hi = mid-1;
+    }
+    else { 
+      *field = info->color;
+      return fname;
+    }    
+  }
+  bbcode_invalid("bbcode: unknown %s: %s\n", fname, value);
+  *field = IC_COLOR_NONE;
+  return fname;
+}
+
+static const char* attr_update_sgr( const char* fname, attr_t* attr, const char* value ) {
+  *attr = attr_update_with(*attr, attr_from_sgr(value, ic_strlen(value)));
+  return fname;
+}
+
+static void attr_update_width( width_t* pwidth, char default_fill, const char* value ) {
+  // parse width value: <width>;<left|center|right>;<fill>;<cut>
+  width_t width;
+  memset(&width, 0, sizeof(width));
+  width.fill = default_fill;   // use 0 for no-fill (as for max-width)
+  if (ic_atoz(value, &width.w)) {     
+    ssize_t i = 0;
+    while( value[i] != ';' && value[i] != 0 ) { i++; }
+    if (value[i] == ';') {
+      i++;
+      ssize_t len = 0;    
+      while( value[i+len] != ';' && value[i+len] != 0 ) { len++; }
+      if (len == 4 && ic_istarts_with(value+i,"left")) {
+        width.align = IC_ALIGN_LEFT;
+      }
+      else if (len == 5 && ic_istarts_with(value+i,"right")) {
+        width.align = IC_ALIGN_RIGHT;
+      }
+      else if (len == 6 && ic_istarts_with(value+i,"center")) {
+        width.align = IC_ALIGN_CENTER;
+      }
+      i += len;
+      if (value[i] == ';') {
+        i++; len = 0;
+        while( value[i+len] != ';' && value[i+len] != 0 ) { len++; }
+        if (len == 1) { width.fill = value[i]; }
+        i+= len;
+        if (value[i] == ';') {
+          i++; len = 0;
+          while( value[i+len] != ';' && value[i+len] != 0 ) { len++; }
+          if ((len == 2 && ic_istarts_with(value+i,"on")) || (len == 1 && value[i] == '1')) { width.dots = true; }
+          i += len;
+        }
+      }
+    }
+  }
+  else {
+    bbcode_invalid("bbcode: illegal width: %s\n", value);
+  }
+  *pwidth = width;
+}
+
+static const char* attr_update_ansi_color( const char* fname, ic_color_t* color, const char* value ) {
+  ssize_t num = 0;
+  if (ic_atoz(value, &num) && num >= 0 && num <= 256) {
+    *color = color_from_ansi256(num);
+  }
+  return fname;
+}
+
+
+static const char* attr_update_property( tag_t* tag, const char* attr_name, const char* value ) {
+  const char* fname = NULL;
+  fname = "bold";
+  if (strcmp(attr_name,fname) == 0) {    
+    signed int b = IC_NONE;    
+    attr_update_bool(fname,&b, value); 
+    if (b != IC_NONE) { tag->attr.x.bold = b; }
+    return fname;
+  }
+  fname = "italic";
+  if (strcmp(attr_name,fname) == 0) {    
+    signed int b = IC_NONE;      
+    attr_update_bool(fname,&b, value); 
+    if (b != IC_NONE) { tag->attr.x.italic = b; }
+    return fname;
+  }
+  fname = "underline";
+  if (strcmp(attr_name,fname) == 0) {  
+    signed int b = IC_NONE;        
+    attr_update_bool(fname,&b, value); 
+    if (b != IC_NONE) { tag->attr.x.underline = b; }
+    return fname;
+  }
+  fname = "reverse";
+  if (strcmp(attr_name,fname) == 0) {
+    signed int b = IC_NONE;          
+    attr_update_bool(fname,&b, value); 
+    if (b != IC_NONE) { tag->attr.x.reverse = b; }
+    return fname;
+  }
+  fname = "color";
+  if (strcmp(attr_name,fname) == 0) {
+    unsigned int color = IC_COLOR_NONE;
+    attr_update_color(fname, &color, value);
+    if (color != IC_COLOR_NONE) { tag->attr.x.color = color; }
+    return fname;
+  }
+  fname = "bgcolor";
+  if (strcmp(attr_name,fname) == 0) {
+    unsigned int color = IC_COLOR_NONE;
+    attr_update_color(fname, &color, value);
+    if (color != IC_COLOR_NONE) { tag->attr.x.bgcolor = color; }
+    return fname;
+  }
+  fname = "ansi-sgr";
+  if (strcmp(attr_name,fname) == 0) {
+    attr_update_sgr(fname, &tag->attr, value);
+    return fname;
+  }
+  fname = "ansi-color";
+  if (strcmp(attr_name,fname) == 0) {
+    ic_color_t color = IC_COLOR_NONE;;
+    attr_update_ansi_color(fname, &color, value);
+    if (color != IC_COLOR_NONE) { tag->attr.x.color = color; }
+    return fname;
+  }
+  fname = "ansi-bgcolor";
+  if (strcmp(attr_name,fname) == 0) {
+    ic_color_t color = IC_COLOR_NONE;;
+    attr_update_ansi_color(fname, &color, value);
+    if (color != IC_COLOR_NONE) { tag->attr.x.bgcolor = color; }
+    return fname;
+  }  
+  fname = "width";
+  if (strcmp(attr_name,fname) == 0) {
+    attr_update_width(&tag->width, ' ', value);
+    return fname;
+  }
+  fname = "max-width";
+  if (strcmp(attr_name,fname) == 0) {
+    attr_update_width(&tag->width, 0, value);
+    return "width";
+  }    
+  else {
+    return NULL;
+  }
+}
+
+static const style_t builtin_styles[] = {
+  { "b",  { { IC_COLOR_NONE, IC_ON  , IC_NONE, IC_COLOR_NONE, IC_NONE, IC_NONE } } },
+  { "r",  { { IC_COLOR_NONE, IC_NONE, IC_ON  , IC_COLOR_NONE, IC_NONE, IC_NONE } } },
+  { "u",  { { IC_COLOR_NONE, IC_NONE, IC_NONE, IC_COLOR_NONE, IC_ON  , IC_NONE } } },
+  { "i",  { { IC_COLOR_NONE, IC_NONE, IC_NONE, IC_COLOR_NONE, IC_NONE, IC_ON   } } },
+  { "em", { { IC_COLOR_NONE, IC_ON  , IC_NONE, IC_COLOR_NONE, IC_NONE, IC_NONE } } }, // bold
+  { "url",{ { IC_COLOR_NONE, IC_NONE, IC_NONE, IC_COLOR_NONE, IC_ON,   IC_NONE } } }, // underline
+  { NULL, { { IC_COLOR_NONE, IC_NONE, IC_NONE, IC_COLOR_NONE, IC_NONE, IC_NONE } } }
+};
+
+static void attr_update_with_styles( tag_t* tag, const char* attr_name, const char* value, 
+                                             bool usebgcolor, const style_t* styles, ssize_t count ) 
+{
+  // direct hex color?
+  if (attr_name[0] == '#' && (value == NULL || value[0]==0)) {
+    value = attr_name;
+    attr_name = (usebgcolor ? "bgcolor" : "color");
+  }
+  // first try if it is a builtin property
+  const char* name;
+  if ((name = attr_update_property(tag,attr_name,value)) != NULL) {
+    if (tag->name != NULL) tag->name = name;
+    return;
+  }
+  // then check all styles
+  while( count-- > 0 ) {
+    const style_t* style = styles + count;
+    if (strcmp(style->name,attr_name) == 0) {
+      tag->attr = attr_update_with(tag->attr,style->attr);
+      if (tag->name != NULL) tag->name = style->name;
+      return;
+    }    
+  }
+  // check builtin styles; todo: binary search?
+  for( const style_t* style = builtin_styles; style->name != NULL; style++) {
+    if (strcmp(style->name,attr_name) == 0) {
+      tag->attr = attr_update_with(tag->attr,style->attr);
+      if (tag->name != NULL) tag->name = style->name;
+      return;
+    }
+  }
+  // check colors as a style
+  ssize_t lo = 0;
+  ssize_t hi = IC_HTML_COLOR_COUNT-1;
+  while( lo <= hi ) {
+    ssize_t mid = (lo + hi) / 2;
+    style_color_t* info = &html_colors[mid];
+    int cmp = strcmp(info->name,attr_name);    
+    if (cmp < 0) {
+      lo = mid+1;
+    }
+    else if (cmp > 0) {
+      hi = mid-1;
+    }
+    else {
+      attr_t cattr = attr_none();
+      if (usebgcolor) { cattr.x.bgcolor = info->color; }
+                else  { cattr.x.color = info->color; }
+      tag->attr = attr_update_with(tag->attr,cattr);
+      if (tag->name != NULL) tag->name = info->name;
+      return;
+    }
+  }
+  // not found
+  bbcode_invalid("bbcode: unknown style: %s\n", attr_name);  
+}
+
+
+ic_private attr_t bbcode_style( bbcode_t* bb, const char* style_name ) {
+  tag_t tag;
+  tag_init(&tag);
+  attr_update_with_styles( &tag, style_name, NULL, false, bb->styles, bb->styles_count );
+  return tag.attr;
+}
+
+//-------------------------------------------------------------
+// Parse tags
+//-------------------------------------------------------------
+
+ic_private const char* parse_skip_white(const char* s) {
+  while( *s != 0 && *s != ']') {
+    if (!(*s == ' ' || *s == '\t' || *s == '\n' || *s == '\r')) break;
+    s++;
+  }
+  return s;
+}
+
+ic_private const char* parse_skip_to_white(const char* s) {
+  while( *s != 0 && *s != ']') {  
+    if (*s == ' ' || *s == '\t' || *s == '\n' || *s == '\r') break;
+    s++;
+  }
+  return parse_skip_white(s);
+}
+
+ic_private const char* parse_skip_to_end(const char* s) {
+  while( *s != 0 && *s != ']' ) { s++; }    
+  return s;
+}
+
+ic_private const char* parse_attr_name(const char* s) {
+  if (*s == '#') {
+    s++; // hex rgb color as id
+    while( *s != 0 && *s != ']') {
+      if (!((*s >= 'a' && *s <= 'f') || (*s >= 'A' && *s <= 'Z') || (*s >= '0' && *s <= '9'))) break;
+      s++;
+    }
+  }
+  else {
+    while( *s != 0 && *s != ']') {
+      if (!((*s >= 'a' && *s <= 'z') || (*s >= 'A' && *s <= 'Z') || 
+            (*s >= '0' && *s <= '9') || *s == '_' || *s == '-')) break;
+      s++;
+    }
+  }    
+  return s;
+}
+
+ic_private const char* parse_value(const char* s, const char** start, const char** end) {
+  if (*s == '"') {
+    s++;
+    *start = s;
+    while( *s != 0 ) {
+      if (*s == '"') break;
+      s++;
+    }
+    *end = s;      
+    if (*s == '"') { s++; }
+  }
+  else if (*s == '#') {
+    *start = s;
+    s++;
+    while( *s != 0 ) {
+      if (!((*s >= 'a' && *s <= 'f') || (*s >= 'A' && *s <= 'Z') || (*s >= '0' && *s <= '9'))) break;
+      s++;
+    }
+    *end = s;
+  }
+  else {
+    *start = s;
+    while( *s != 0 ) {
+      if (!((*s >= 'a' && *s <= 'z') || (*s >= 'A' && *s <= 'F') || (*s >= '0' && *s <= '9') || *s == '-' || *s == '_')) break;
+      s++;
+    }
+    *end = s;
+  }  
+  return s;  
+}
+
+ic_private const char* parse_tag_value( tag_t* tag, char* idbuf, const char* s, const style_t* styles, ssize_t scount ) {
+  // parse: \s*[\w-]+\s*(=\s*<value>)
+  bool usebgcolor = false;
+  const char* id = s;
+  const char* idend = parse_attr_name(id);
+  const char* val = NULL;
+  const char* valend = NULL;  
+  if (id == idend) {
+    bbcode_invalid("bbcode: empty identifier? %.10s...\n", id );
+    return parse_skip_to_white(id);
+  }
+  // "on" bgcolor?
+  s = parse_skip_white(idend);
+  if (idend - id == 2 && ic_strnicmp(id,"on",2) == 0 && *s != '=') {
+    usebgcolor = true;
+    id = s;
+    idend = parse_attr_name(id);
+    if (id == idend) {
+      bbcode_invalid("bbcode: empty identifier follows 'on'? %.10s...\n", id );
+      return parse_skip_to_white(id);
+    }
+    s = parse_skip_white(idend);      
+  }
+  // value
+  if (*s == '=') {
+    s++;
+    s = parse_skip_white(s);
+    s = parse_value(s, &val, &valend);
+    s = parse_skip_white(s);
+  }  
+  // limit name and attr to 128 bytes
+  char valbuf[128];
+  ic_strncpy( idbuf, 128, id, idend - id);
+  ic_strncpy( valbuf, 128, val, valend - val);
+  ic_str_tolower(idbuf);
+  ic_str_tolower(valbuf);
+  attr_update_with_styles( tag, idbuf, valbuf, usebgcolor, styles, scount );  
+  return s;
+}
+
+static const char* parse_tag_values( tag_t* tag, char* idbuf, const char* s, const style_t* styles, ssize_t scount ) {
+  s = parse_skip_white(s);  
+  idbuf[0] = 0;
+  ssize_t count = 0;
+  while( *s != 0 && *s != ']') {
+    char idbuf_next[128];
+    s = parse_tag_value(tag, (count==0 ? idbuf : idbuf_next), s, styles, scount);
+    count++;
+  }
+  if (*s == ']') { s++; }
+  return s;
+}
+
+static const char* parse_tag( tag_t* tag, char* idbuf, bool* open, bool* pre, const char* s, const style_t* styles, ssize_t scount ) {
+  *open = true;
+  *pre = false;
+  if (*s != '[') return s;
+  s = parse_skip_white(s+1);
+  if (*s == '!') { // pre
+    *pre = true;
+    s = parse_skip_white(s+1);  
+  }  
+  else if (*s == '/') { 
+    *open = false; 
+    s = parse_skip_white(s+1); 
+  };
+  s = parse_tag_values( tag, idbuf, s, styles, scount);
+  return s;
+}
+
+
+//---------------------------------------------------------
+// Styles
+//---------------------------------------------------------
+
+static void bbcode_parse_tag_content( bbcode_t* bb, const char* s, tag_t* tag ) {
+  tag_init(tag);
+  if (s != NULL) { 
+    char idbuf[128];
+    parse_tag_values(tag, idbuf, s, bb->styles, bb->styles_count);
+  }
+}
+
+ic_private void bbcode_style_def( bbcode_t* bb, const char* style_name, const char* s ) {
+  tag_t tag;
+  bbcode_parse_tag_content( bb, s, &tag);
+  bbcode_style_add(bb, style_name, tag.attr);
+}
+
+ic_private void bbcode_style_open( bbcode_t* bb, const char* fmt ) {
+  tag_t tag;
+  bbcode_parse_tag_content(bb, fmt, &tag);
+  term_set_attr( bb->term, bbcode_open(bb, 0, &tag, term_get_attr(bb->term)) );
+}
+
+ic_private void bbcode_style_close( bbcode_t* bb, const char* fmt ) {
+  const ssize_t base = bb->tags_nesting - 1; // as we end a style
+  tag_t tag;
+  bbcode_parse_tag_content(bb, fmt, &tag);  
+  tag_t prev;
+  if (bbcode_close(bb, base, tag.name, &prev)) {
+    term_set_attr( bb->term, prev.attr );
+  }
+}
+
+//---------------------------------------------------------
+// Restrict to width
+//---------------------------------------------------------
+
+static void bbcode_restrict_width( ssize_t start, width_t width, stringbuf_t* out, attrbuf_t* attr_out ) {
+  if (width.w <= 0) return;
+  assert(start <= sbuf_len(out));
+  assert(attr_out == NULL || sbuf_len(out) == attrbuf_len(attr_out));
+  const char*   s   = sbuf_string(out) + start;
+  const ssize_t len = sbuf_len(out) - start;
+  const ssize_t w   = str_column_width(s);
+  if (w == width.w) return; // fits exactly
+  if (w > width.w) {
+    // too large
+    ssize_t innerw = (width.dots && width.w > 3 ? width.w-3 : width.w);
+    if (width.align == IC_ALIGN_RIGHT) {
+      // right align
+      const ssize_t ndel = str_skip_until_fit( s, innerw );
+      sbuf_delete_at( out, start, ndel );
+      attrbuf_delete_at( attr_out, start, ndel );
+      if (innerw < width.w) {
+        // add dots
+        sbuf_insert_at( out, "...", start );
+        attr_t attr = attrbuf_attr_at(attr_out, start);
+        attrbuf_insert_at( attr_out, start, 3, attr);
+      }
+    }
+    else {
+      // left or center align
+      ssize_t count = str_take_while_fit( s, innerw );
+      sbuf_delete_at( out, start + count, len - count );
+      attrbuf_delete_at( attr_out, start + count, len - count );
+      if (innerw < width.w) {
+        // add dots
+        attr_t attr = attrbuf_attr_at(attr_out,start);
+        attrbuf_append_n( out, attr_out, "...", 3, attr );
+      }
+    }
+  }
+  else {
+    // too short, pad to width
+    const ssize_t diff = (width.w - w);
+    const ssize_t pad_left  = (width.align == IC_ALIGN_RIGHT ? diff : (width.align == IC_ALIGN_LEFT  ? 0 : diff / 2));
+    const ssize_t pad_right = (width.align == IC_ALIGN_LEFT  ? diff : (width.align == IC_ALIGN_RIGHT ? 0 : diff - pad_left));
+    if (width.fill != 0 && pad_left > 0) {
+      const attr_t attr = attrbuf_attr_at(attr_out,start);
+      for( ssize_t i = 0; i < pad_left; i++) {  // todo: optimize
+        sbuf_insert_char_at(out, width.fill, start);
+      }
+      attrbuf_insert_at( attr_out, start, pad_left, attr );
+    }
+    if (width.fill != 0 && pad_right > 0) {
+      const attr_t attr = attrbuf_attr_at(attr_out,sbuf_len(out) - 1);
+      char buf[2];
+      buf[0] = width.fill;
+      buf[1] = 0;        
+      for( ssize_t i = 0; i < pad_right; i++) {  // todo: optimize
+        attrbuf_append_n( out, attr_out, buf, 1, attr );
+      }      
+    }
+  }
+}
+
+//---------------------------------------------------------
+// Print
+//---------------------------------------------------------
+
+ic_private ssize_t bbcode_process_tag( bbcode_t* bb, const char* s, const ssize_t nesting_base, 
+                                        stringbuf_t* out, attrbuf_t* attr_out, attr_t* cur_attr ) {
+  assert(*s == '[');
+  tag_t tag;
+  tag_init(&tag);  
+  bool open = true;
+  bool ispre = false;
+  char idbuf[128];
+  const char* end = parse_tag( &tag, idbuf, &open, &ispre, s, bb->styles, bb->styles_count ); // todo: styles
+  assert(end > s);
+  if (open) {
+    if (!ispre) {
+      // open tag
+      *cur_attr = bbcode_open( bb, sbuf_len(out), &tag, *cur_attr );
+    }
+    else {
+      // scan pre to end tag
+      attr_t attr = attr_update_with(*cur_attr, tag.attr);
+      char pre[132];
+      if (snprintf(pre, 132, "[/%s]", idbuf) < ssizeof(pre)) {
+        const char* etag = strstr(end,pre);
+        if (etag == NULL) {
+          const ssize_t len = ic_strlen(end);
+          attrbuf_append_n(out, attr_out, end, len, attr);
+          end += len;
+        }
+        else {
+          attrbuf_append_n(out, attr_out, end, (etag - end), attr);
+          end = etag + ic_strlen(pre);
+        }
+      }
+    }
+  }
+  else {
+    // pop the tag
+    tag_t prev;
+    if (bbcode_close( bb, nesting_base, tag.name, &prev)) {
+      *cur_attr = prev.attr;
+      if (prev.width.w > 0) {
+        // closed a width tag; restrict the output to width
+        bbcode_restrict_width( prev.pos, prev.width, out, attr_out);
+      }
+    }
+  }  
+  return (end - s);
+}
+
+ic_private void bbcode_append( bbcode_t* bb, const char* s, stringbuf_t* out, attrbuf_t* attr_out ) {
+  if (bb == NULL || s == NULL) return;
+  attr_t attr = attr_none();
+  const ssize_t base = bb->tags_nesting; // base; will not be popped
+  ssize_t i = 0;
+  while( s[i] != 0 ) {
+    // handle no tags in bulk
+    ssize_t nobb = 0;
+    char c;
+    while( (c = s[i+nobb]) != 0) {
+      if (c == '[' || c == '\\') { break; }
+      if (c == '\x1B' && s[i+nobb+1] == '[') {
+        nobb++; // don't count 'ESC[' as a tag opener
+      }
+      nobb++;
+    }
+    if (nobb > 0) { attrbuf_append_n(out, attr_out, s+i, nobb, attr); }
+    i += nobb;
+    // tag
+    if (s[i] == '[') {
+      i += bbcode_process_tag(bb, s+i, base, out, attr_out, &attr);
+    }
+    else if (s[i] == '\\') {
+      if (s[i+1] == '\\' || s[i+1] == '[') {
+        attrbuf_append_n(out, attr_out, s+i+1, 1, attr); // escape '\[' and '\\' 
+        i += 2;
+      }
+      else {
+        attrbuf_append_n(out, attr_out, s+i, 1, attr);  // pass '\\' as is
+        i++;
+      }
+    }
+  }
+  // pop unclosed openings
+  assert(bb->tags_nesting >= base);
+  while( bb->tags_nesting > base ) {
+    bbcode_tag_pop(bb,NULL);
+  };
+}
+
+ic_private void bbcode_print( bbcode_t* bb, const char* s ) {
+  if (bb->out == NULL || bb->out_attrs == NULL || s == NULL) return;
+  assert(sbuf_len(bb->out) == 0 && attrbuf_len(bb->out_attrs) == 0);
+  bbcode_append( bb, s, bb->out, bb->out_attrs );
+  term_write_formatted( bb->term, sbuf_string(bb->out), attrbuf_attrs(bb->out_attrs,sbuf_len(bb->out)) );
+  attrbuf_clear(bb->out_attrs);
+  sbuf_clear(bb->out);
+}
+
+ic_private void bbcode_println( bbcode_t* bb, const char* s ) {
+  bbcode_print(bb,s);
+  term_writeln(bb->term, "");
+}
+
+ic_private void bbcode_vprintf( bbcode_t* bb, const char* fmt, va_list args  ) {
+  if (bb->vout == NULL || fmt == NULL) return;
+  assert(sbuf_len(bb->vout) == 0);
+  sbuf_append_vprintf(bb->vout,fmt,args);
+  bbcode_print(bb, sbuf_string(bb->vout));
+  sbuf_clear(bb->vout);
+}
+
+ic_private void bbcode_printf( bbcode_t* bb, const char* fmt, ... ) {
+  va_list args;
+  va_start(args,fmt);
+  bbcode_vprintf(bb,fmt,args);
+  va_end(args);
+}
+
+ic_private ssize_t bbcode_column_width( bbcode_t* bb, const char* s ) {
+  if (s==NULL || s[0] == 0) return 0;
+  if (bb->vout == NULL) { return str_column_width(s); }
+  assert(sbuf_len(bb->vout) == 0); 
+  bbcode_append( bb, s, bb->vout, NULL);
+  const ssize_t w = str_column_width(sbuf_string(bb->vout));
+  sbuf_clear(bb->vout);
+  return w;
+}

extern/isocline/src/bbcode.h

@@ -0,0 +1,37 @@
+/* ----------------------------------------------------------------------------
+  Copyright (c) 2021, Daan Leijen
+  This is free software; you can redistribute it and/or modify it
+  under the terms of the MIT License. A copy of the license can be
+  found in the "LICENSE" file at the root of this distribution.
+-----------------------------------------------------------------------------*/
+#pragma once
+#ifndef IC_BBCODE_H
+#define IC_BBCODE_H
+
+#include <stdarg.h>
+#include "common.h"
+#include "term.h"
+
+struct bbcode_s;
+typedef struct bbcode_s bbcode_t;
+
+ic_private bbcode_t* bbcode_new( alloc_t* mem, term_t* term );
+ic_private void bbcode_free( bbcode_t* bb );
+
+ic_private void bbcode_style_add( bbcode_t* bb, const char* style_name, attr_t attr );
+ic_private void bbcode_style_def( bbcode_t* bb, const char* style_name, const char* s );
+ic_private void bbcode_style_open( bbcode_t* bb, const char* fmt );
+ic_private void bbcode_style_close( bbcode_t* bb, const char* fmt );
+ic_private attr_t bbcode_style( bbcode_t* bb, const char* style_name );
+
+ic_private void bbcode_print( bbcode_t* bb, const char* s );
+ic_private void bbcode_println( bbcode_t* bb, const char* s );
+ic_private void bbcode_printf( bbcode_t* bb, const char* fmt, ... );
+ic_private void bbcode_vprintf( bbcode_t* bb, const char* fmt, va_list args );
+
+ic_private ssize_t bbcode_column_width( bbcode_t* bb, const char* s );
+
+// allows `attr_out == NULL`.
+ic_private void bbcode_append( bbcode_t* bb, const char* s, stringbuf_t* out, attrbuf_t* attr_out );
+
+#endif // IC_BBCODE_H

extern/isocline/src/bbcode_colors.c

@@ -0,0 +1,194 @@
+/* ----------------------------------------------------------------------------
+  Copyright (c) 2021, Daan Leijen
+  This is free software; you can redistribute it and/or modify it
+  under the terms of the MIT License. A copy of the license can be
+  found in the "LICENSE" file at the root of this distribution.
+-----------------------------------------------------------------------------*/
+
+// This file is included from "bbcode.c" and contains html color names
+
+#include "common.h"
+
+typedef struct style_color_s {
+  const char* name;
+  ic_color_t color;
+} style_color_t;
+
+#define IC_HTML_COLOR_COUNT (172)
+
+// ordered list of HTML color names (so we can use binary search)
+static style_color_t html_colors[IC_HTML_COLOR_COUNT+1] = {
+  { "aliceblue",      IC_RGB(0xf0f8ff) },
+  { "ansi-aqua",      IC_ANSI_AQUA },
+  { "ansi-black",     IC_ANSI_BLACK },
+  { "ansi-blue",      IC_ANSI_BLUE },
+  { "ansi-cyan",      IC_ANSI_CYAN },
+  { "ansi-darkgray",  IC_ANSI_DARKGRAY },
+  { "ansi-darkgrey",  IC_ANSI_DARKGRAY },
+  { "ansi-default",   IC_ANSI_DEFAULT },
+  { "ansi-fuchsia",   IC_ANSI_FUCHSIA },
+  { "ansi-gray",      IC_ANSI_GRAY },
+  { "ansi-green",     IC_ANSI_GREEN },
+  { "ansi-grey",      IC_ANSI_GRAY },
+  { "ansi-lightgray", IC_ANSI_LIGHTGRAY },
+  { "ansi-lightgrey", IC_ANSI_LIGHTGRAY },
+  { "ansi-lime" ,     IC_ANSI_LIME },
+  { "ansi-magenta",   IC_ANSI_MAGENTA },
+  { "ansi-maroon",    IC_ANSI_MAROON },
+  { "ansi-navy",      IC_ANSI_NAVY },
+  { "ansi-olive",     IC_ANSI_OLIVE },
+  { "ansi-purple",    IC_ANSI_PURPLE },
+  { "ansi-red",       IC_ANSI_RED },
+  { "ansi-silver",    IC_ANSI_SILVER },
+  { "ansi-teal",      IC_ANSI_TEAL },
+  { "ansi-white",     IC_ANSI_WHITE },
+  { "ansi-yellow",    IC_ANSI_YELLOW },
+  { "antiquewhite",   IC_RGB(0xfaebd7) },
+  { "aqua", IC_RGB(0x00ffff) },
+  { "aquamarine", IC_RGB(0x7fffd4) },
+  { "azure", IC_RGB(0xf0ffff) },
+  { "beige", IC_RGB(0xf5f5dc) },
+  { "bisque", IC_RGB(0xffe4c4) },
+  { "black", IC_RGB(0x000000) },
+  { "blanchedalmond", IC_RGB(0xffebcd) },
+  { "blue", IC_RGB(0x0000ff) },
+  { "blueviolet", IC_RGB(0x8a2be2) },
+  { "brown", IC_RGB(0xa52a2a) },
+  { "burlywood", IC_RGB(0xdeb887) },
+  { "cadetblue", IC_RGB(0x5f9ea0) },
+  { "chartreuse", IC_RGB(0x7fff00) },
+  { "chocolate", IC_RGB(0xd2691e) },
+  { "coral", IC_RGB(0xff7f50) },
+  { "cornflowerblue", IC_RGB(0x6495ed) },
+  { "cornsilk", IC_RGB(0xfff8dc) },
+  { "crimson", IC_RGB(0xdc143c) },
+  { "cyan", IC_RGB(0x00ffff) },
+  { "darkblue", IC_RGB(0x00008b) },
+  { "darkcyan", IC_RGB(0x008b8b) },
+  { "darkgoldenrod", IC_RGB(0xb8860b) },
+  { "darkgray", IC_RGB(0xa9a9a9) },
+  { "darkgreen", IC_RGB(0x006400) },
+  { "darkgrey", IC_RGB(0xa9a9a9) },
+  { "darkkhaki", IC_RGB(0xbdb76b) },
+  { "darkmagenta", IC_RGB(0x8b008b) },
+  { "darkolivegreen", IC_RGB(0x556b2f) },
+  { "darkorange", IC_RGB(0xff8c00) },
+  { "darkorchid", IC_RGB(0x9932cc) },
+  { "darkred", IC_RGB(0x8b0000) },
+  { "darksalmon", IC_RGB(0xe9967a) },
+  { "darkseagreen", IC_RGB(0x8fbc8f) },
+  { "darkslateblue", IC_RGB(0x483d8b) },
+  { "darkslategray", IC_RGB(0x2f4f4f) },
+  { "darkslategrey", IC_RGB(0x2f4f4f) },
+  { "darkturquoise", IC_RGB(0x00ced1) },
+  { "darkviolet", IC_RGB(0x9400d3) },
+  { "deeppink", IC_RGB(0xff1493) },
+  { "deepskyblue", IC_RGB(0x00bfff) },
+  { "dimgray", IC_RGB(0x696969) },
+  { "dimgrey", IC_RGB(0x696969) },
+  { "dodgerblue", IC_RGB(0x1e90ff) },
+  { "firebrick", IC_RGB(0xb22222) },
+  { "floralwhite", IC_RGB(0xfffaf0) },
+  { "forestgreen", IC_RGB(0x228b22) },
+  { "fuchsia", IC_RGB(0xff00ff) },
+  { "gainsboro", IC_RGB(0xdcdcdc) },
+  { "ghostwhite", IC_RGB(0xf8f8ff) },
+  { "gold", IC_RGB(0xffd700) },
+  { "goldenrod", IC_RGB(0xdaa520) },
+  { "gray", IC_RGB(0x808080) },
+  { "green", IC_RGB(0x008000) },
+  { "greenyellow", IC_RGB(0xadff2f) },
+  { "grey", IC_RGB(0x808080) },
+  { "honeydew", IC_RGB(0xf0fff0) },
+  { "hotpink", IC_RGB(0xff69b4) },
+  { "indianred", IC_RGB(0xcd5c5c) },
+  { "indigo", IC_RGB(0x4b0082) },
+  { "ivory", IC_RGB(0xfffff0) },
+  { "khaki", IC_RGB(0xf0e68c) },
+  { "lavender", IC_RGB(0xe6e6fa) },
+  { "lavenderblush", IC_RGB(0xfff0f5) },
+  { "lawngreen", IC_RGB(0x7cfc00) },
+  { "lemonchiffon", IC_RGB(0xfffacd) },
+  { "lightblue", IC_RGB(0xadd8e6) },
+  { "lightcoral", IC_RGB(0xf08080) },
+  { "lightcyan", IC_RGB(0xe0ffff) },
+  { "lightgoldenrodyellow", IC_RGB(0xfafad2) },
+  { "lightgray", IC_RGB(0xd3d3d3) },
+  { "lightgreen", IC_RGB(0x90ee90) },
+  { "lightgrey", IC_RGB(0xd3d3d3) },
+  { "lightpink", IC_RGB(0xffb6c1) },
+  { "lightsalmon", IC_RGB(0xffa07a) },
+  { "lightseagreen", IC_RGB(0x20b2aa) },
+  { "lightskyblue", IC_RGB(0x87cefa) },
+  { "lightslategray", IC_RGB(0x778899) },
+  { "lightslategrey", IC_RGB(0x778899) },
+  { "lightsteelblue", IC_RGB(0xb0c4de) },
+  { "lightyellow", IC_RGB(0xffffe0) },
+  { "lime", IC_RGB(0x00ff00) },
+  { "limegreen", IC_RGB(0x32cd32) },
+  { "linen", IC_RGB(0xfaf0e6) },
+  { "magenta", IC_RGB(0xff00ff) },
+  { "maroon", IC_RGB(0x800000) },
+  { "mediumaquamarine", IC_RGB(0x66cdaa) },
+  { "mediumblue", IC_RGB(0x0000cd) },
+  { "mediumorchid", IC_RGB(0xba55d3) },
+  { "mediumpurple", IC_RGB(0x9370db) },
+  { "mediumseagreen", IC_RGB(0x3cb371) },
+  { "mediumslateblue", IC_RGB(0x7b68ee) },
+  { "mediumspringgreen", IC_RGB(0x00fa9a) },
+  { "mediumturquoise", IC_RGB(0x48d1cc) },
+  { "mediumvioletred", IC_RGB(0xc71585) },
+  { "midnightblue", IC_RGB(0x191970) },
+  { "mintcream", IC_RGB(0xf5fffa) },
+  { "mistyrose", IC_RGB(0xffe4e1) },
+  { "moccasin", IC_RGB(0xffe4b5) },
+  { "navajowhite", IC_RGB(0xffdead) },
+  { "navy", IC_RGB(0x000080) },
+  { "oldlace", IC_RGB(0xfdf5e6) },
+  { "olive", IC_RGB(0x808000) },
+  { "olivedrab", IC_RGB(0x6b8e23) },
+  { "orange", IC_RGB(0xffa500) },
+  { "orangered", IC_RGB(0xff4500) },
+  { "orchid", IC_RGB(0xda70d6) },
+  { "palegoldenrod", IC_RGB(0xeee8aa) },
+  { "palegreen", IC_RGB(0x98fb98) },
+  { "paleturquoise", IC_RGB(0xafeeee) },
+  { "palevioletred", IC_RGB(0xdb7093) },
+  { "papayawhip", IC_RGB(0xffefd5) },
+  { "peachpuff", IC_RGB(0xffdab9) },
+  { "peru", IC_RGB(0xcd853f) },
+  { "pink", IC_RGB(0xffc0cb) },
+  { "plum", IC_RGB(0xdda0dd) },
+  { "powderblue", IC_RGB(0xb0e0e6) },
+  { "purple", IC_RGB(0x800080) },
+  { "rebeccapurple", IC_RGB(0x663399) },
+  { "red", IC_RGB(0xff0000) },
+  { "rosybrown", IC_RGB(0xbc8f8f) },
+  { "royalblue", IC_RGB(0x4169e1) },
+  { "saddlebrown", IC_RGB(0x8b4513) },
+  { "salmon", IC_RGB(0xfa8072) },
+  { "sandybrown", IC_RGB(0xf4a460) },
+  { "seagreen", IC_RGB(0x2e8b57) },
+  { "seashell", IC_RGB(0xfff5ee) },
+  { "sienna", IC_RGB(0xa0522d) },
+  { "silver", IC_RGB(0xc0c0c0) },
+  { "skyblue", IC_RGB(0x87ceeb) },
+  { "slateblue", IC_RGB(0x6a5acd) },
+  { "slategray", IC_RGB(0x708090) },
+  { "slategrey", IC_RGB(0x708090) },
+  { "snow", IC_RGB(0xfffafa) },
+  { "springgreen", IC_RGB(0x00ff7f) },
+  { "steelblue", IC_RGB(0x4682b4) },
+  { "tan", IC_RGB(0xd2b48c) },
+  { "teal", IC_RGB(0x008080) },
+  { "thistle", IC_RGB(0xd8bfd8) },
+  { "tomato", IC_RGB(0xff6347) },
+  { "turquoise", IC_RGB(0x40e0d0) },
+  { "violet", IC_RGB(0xee82ee) },
+  { "wheat", IC_RGB(0xf5deb3) },
+  { "white", IC_RGB(0xffffff) },
+  { "whitesmoke", IC_RGB(0xf5f5f5) },
+  { "yellow", IC_RGB(0xffff00) },
+  { "yellowgreen", IC_RGB(0x9acd32) },
+  {NULL, 0}
+}; 

extern/isocline/src/common.c

@@ -0,0 +1,347 @@
+/* ----------------------------------------------------------------------------
+  Copyright (c) 2021, Daan Leijen
+  This is free software; you can redistribute it and/or modify it
+  under the terms of the MIT License. A copy of the license can be
+  found in the "LICENSE" file at the root of this distribution.
+-----------------------------------------------------------------------------*/
+
+#include <string.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include "common.h"
+
+
+//-------------------------------------------------------------
+// String wrappers for ssize_t
+//-------------------------------------------------------------
+
+ic_private ssize_t ic_strlen( const char* s ) {
+  if (s==NULL) return 0;
+  return to_ssize_t(strlen(s));
+}
+
+ic_private void ic_memmove( void* dest, const void* src, ssize_t n ) {
+  assert(dest!=NULL && src != NULL);
+  if (n <= 0) return;
+  memmove(dest,src,to_size_t(n));
+}
+
+
+ic_private void ic_memcpy( void* dest, const void* src, ssize_t n ) {
+  assert(dest!=NULL && src != NULL);
+  if (dest == NULL || src == NULL || n <= 0) return;
+  memcpy(dest,src,to_size_t(n));
+}
+
+ic_private void ic_memset(void* dest, uint8_t value, ssize_t n) {
+  assert(dest!=NULL);
+  if (dest == NULL || n <= 0) return;
+  memset(dest,(int8_t)value,to_size_t(n));
+}
+
+ic_private bool ic_memnmove( void* dest, ssize_t dest_size, const void* src, ssize_t n ) {
+  assert(dest!=NULL && src != NULL);
+  if (n <= 0) return true;
+  if (dest_size < n) { assert(false); return false; }
+  memmove(dest,src,to_size_t(n));
+  return true;
+}
+
+ic_private bool ic_strcpy( char* dest, ssize_t dest_size /* including 0 */, const char* src) {
+  assert(dest!=NULL && src != NULL);
+  if (dest == NULL || dest_size <= 0) return false;
+  ssize_t slen = ic_strlen(src);
+  if (slen >= dest_size) return false;
+  strcpy(dest,src);
+  assert(dest[slen] == 0);
+  return true;
+}
+
+
+ic_private bool ic_strncpy( char* dest, ssize_t dest_size /* including 0 */, const char* src, ssize_t n) {
+  assert(dest!=NULL && n < dest_size);
+  if (dest == NULL || dest_size <= 0) return false;
+  if (n >= dest_size) return false;
+  if (src==NULL || n <= 0) {
+    dest[0] = 0;
+  }
+  else {
+    strncpy(dest,src,to_size_t(n));
+    dest[n] = 0;  
+  }
+  return true;
+}
+
+//-------------------------------------------------------------
+// String matching
+//-------------------------------------------------------------
+
+ic_public bool ic_starts_with( const char* s, const char* prefix ) {
+  if (s==prefix) return true;
+  if (prefix==NULL) return true;
+  if (s==NULL) return false;
+
+  ssize_t i;
+  for( i = 0; s[i] != 0 && prefix[i] != 0; i++) {
+    if (s[i] != prefix[i]) return false;
+  }
+  return (prefix[i] == 0);
+}
+
+ic_private char ic_tolower( char c ) {
+  return (c >= 'A' && c <= 'Z'  ?  c - 'A' + 'a' : c);
+}
+
+ic_private void ic_str_tolower(char* s) {
+  while(*s != 0) {
+    *s = ic_tolower(*s);
+    s++;
+  }
+}
+
+ic_public bool ic_istarts_with( const char* s, const char* prefix ) {
+  if (s==prefix) return true;
+  if (prefix==NULL) return true;
+  if (s==NULL) return false;
+
+  ssize_t i;
+  for( i = 0; s[i] != 0 && prefix[i] != 0; i++) {
+    if (ic_tolower(s[i]) != ic_tolower(prefix[i])) return false;
+  }
+  return (prefix[i] == 0);
+}
+
+
+ic_private int ic_strnicmp(const char* s1, const char* s2, ssize_t n) {
+  if (s1 == NULL && s2 == NULL) return 0;
+  if (s1 == NULL) return -1;
+  if (s2 == NULL) return 1;
+  ssize_t i;
+  for (i = 0; s1[i] != 0 && i < n; i++) {  // note: if s2[i] == 0 the loop will stop as c1 != c2
+    char c1 = ic_tolower(s1[i]);
+    char c2 = ic_tolower(s2[i]);
+    if (c1 < c2) return -1;
+    if (c1 > c2) return 1;
+  }
+  return ((i >= n || s2[i] == 0) ? 0 : -1);
+}
+
+ic_private int ic_stricmp(const char* s1, const char* s2) {
+  ssize_t len1 = ic_strlen(s1);
+  ssize_t len2 = ic_strlen(s2);
+  if (len1 < len2) return -1;
+  if (len1 > len2) return 1;
+  return (ic_strnicmp(s1, s2, (len1 >= len2 ? len1 : len2)));
+}
+
+
+static const char* ic_stristr(const char* s, const char* pat) {
+  if (s==NULL) return NULL;
+  if (pat==NULL || pat[0] == 0) return s;
+  ssize_t patlen = ic_strlen(pat);
+  for (ssize_t i = 0; s[i] != 0; i++) {
+    if (ic_strnicmp(s + i, pat, patlen) == 0) return (s+i);
+  }
+  return NULL;
+}
+
+ic_private bool ic_contains(const char* big, const char* s) {
+  if (big == NULL) return false;
+  if (s == NULL) return true;
+  return (strstr(big,s) != NULL);
+}
+
+ic_private bool ic_icontains(const char* big, const char* s) {
+  if (big == NULL) return false;
+  if (s == NULL) return true;
+  return (ic_stristr(big,s) != NULL);
+}
+
+
+//-------------------------------------------------------------
+// Unicode
+// QUTF-8: See <https://github.com/koka-lang/koka/blob/master/kklib/include/kklib/string.h>
+// Raw bytes are code points 0xEE000 - 0xEE0FF
+//-------------------------------------------------------------
+#define IC_UNICODE_RAW   ((unicode_t)(0xEE000U))
+
+ic_private unicode_t unicode_from_raw(uint8_t c) {
+  return (IC_UNICODE_RAW + c);
+}
+
+ic_private bool unicode_is_raw(unicode_t u, uint8_t* c) {
+  if (u >= IC_UNICODE_RAW && u <= IC_UNICODE_RAW + 0xFF) {
+    *c = (uint8_t)(u - IC_UNICODE_RAW);
+    return true;
+  }
+  else {
+    return false;
+  }
+}
+
+ic_private void unicode_to_qutf8(unicode_t u, uint8_t buf[5]) {
+  memset(buf, 0, 5);
+  if (u <= 0x7F) {
+    buf[0] = (uint8_t)u;
+  }
+  else if (u <= 0x07FF) {
+    buf[0] = (0xC0 | ((uint8_t)(u >> 6)));
+    buf[1] = (0x80 | (((uint8_t)u) & 0x3F));
+  }
+  else if (u <= 0xFFFF) {
+    buf[0] = (0xE0 |  ((uint8_t)(u >> 12)));
+    buf[1] = (0x80 | (((uint8_t)(u >>  6)) & 0x3F));
+    buf[2] = (0x80 | (((uint8_t)u) & 0x3F));
+  }
+  else if (u <= 0x10FFFF) {
+    if (unicode_is_raw(u, &buf[0])) {
+      buf[1] = 0;
+    }
+    else {
+      buf[0] = (0xF0 |  ((uint8_t)(u >> 18)));
+      buf[1] = (0x80 | (((uint8_t)(u >> 12)) & 0x3F));
+      buf[2] = (0x80 | (((uint8_t)(u >>  6)) & 0x3F));
+      buf[3] = (0x80 | (((uint8_t)u) & 0x3F));
+    }
+  }
+}
+
+// is this a utf8 continuation byte?
+ic_private bool utf8_is_cont(uint8_t c) {
+  return ((c & 0xC0) == 0x80);
+}
+
+ic_private unicode_t unicode_from_qutf8(const uint8_t* s, ssize_t len, ssize_t* count) {
+  unicode_t c0 = 0;
+  if (len <= 0 || s == NULL) {
+    goto fail;
+  }
+  // 1 byte
+  c0 = s[0];
+  if (c0 <= 0x7F && len >= 1) {
+    if (count != NULL) *count = 1;
+    return c0; 
+  }
+  else if (c0 <= 0xC1) { // invalid continuation byte or invalid 0xC0, 0xC1
+    goto fail;
+  }
+  // 2 bytes
+  else if (c0 <= 0xDF && len >= 2 && utf8_is_cont(s[1])) { 
+    if (count != NULL) *count = 2;
+    return (((c0 & 0x1F) << 6) | (s[1] & 0x3F));
+  }
+  // 3 bytes: reject overlong and surrogate halves
+  else if (len >= 3 && 
+           ((c0 == 0xE0 && s[1] >= 0xA0 && s[1] <= 0xBF && utf8_is_cont(s[2])) ||
+            (c0 >= 0xE1 && c0 <= 0xEC && utf8_is_cont(s[1]) && utf8_is_cont(s[2])) 
+          ))
+  {
+    if (count != NULL) *count = 3;
+    return (((c0 & 0x0F) << 12) | ((unicode_t)(s[1] & 0x3F) << 6) | (s[2] & 0x3F));
+  }
+  // 4 bytes: reject overlong
+  else if (len >= 4 && 
+           (((c0 == 0xF0 && s[1] >= 0x90 && s[1] <= 0xBF && utf8_is_cont(s[2]) && utf8_is_cont(s[3])) ||
+            (c0 >= 0xF1 && c0 <= 0xF3 && utf8_is_cont(s[1]) && utf8_is_cont(s[2]) && utf8_is_cont(s[3])) ||
+            (c0 == 0xF4 && s[1] >= 0x80 && s[1] <= 0x8F && utf8_is_cont(s[2]) && utf8_is_cont(s[3]))) 
+          )) 
+  {
+    if (count != NULL) *count = 4;
+    return (((c0 & 0x07) << 18) | ((unicode_t)(s[1] & 0x3F) << 12) | ((unicode_t)(s[2] & 0x3F) << 6) | (s[3] & 0x3F));
+  }  
+fail:
+  if (count != NULL) *count = 1;
+  return unicode_from_raw(s[0]);
+}
+
+
+//-------------------------------------------------------------
+// Debug
+//-------------------------------------------------------------
+
+#if defined(IC_NO_DEBUG_MSG) 
+// nothing
+#elif !defined(IC_DEBUG_TO_FILE)
+ic_private void debug_msg(const char* fmt, ...) {
+  if (getenv("ISOCLINE_DEBUG")) {
+    va_list args;
+    va_start(args, fmt);
+    vfprintf(stderr, fmt, args);
+    va_end(args);
+  }
+}
+#else
+ic_private void debug_msg(const char* fmt, ...) {
+  static int debug_init;
+  static const char* debug_fname = "isocline.debug.txt";
+  // initialize?
+  if (debug_init==0) {
+    debug_init = -1;
+    const char* rdebug = getenv("ISOCLINE_DEBUG");
+    if (rdebug!=NULL && strcmp(rdebug,"1") == 0) {
+      FILE* fdbg = fopen(debug_fname, "w");
+      if (fdbg!=NULL) {
+        debug_init = 1;
+        fclose(fdbg);
+      }
+    }
+  }
+  if (debug_init <= 0) return;
+
+  // write debug messages
+  FILE* fdbg = fopen(debug_fname, "a");
+  if (fdbg==NULL) return;
+  va_list args;
+  va_start(args, fmt);
+  vfprintf(fdbg, fmt, args);
+  fclose(fdbg);
+  va_end(args);
+}
+#endif
+
+
+//-------------------------------------------------------------
+// Allocation
+//-------------------------------------------------------------
+
+ic_private void* mem_malloc(alloc_t* mem, ssize_t sz) {
+  return mem->malloc(to_size_t(sz));
+}
+
+ic_private void* mem_zalloc(alloc_t* mem, ssize_t sz) {
+  void* p = mem_malloc(mem, sz);
+  if (p != NULL) memset(p, 0, to_size_t(sz));
+  return p;
+}
+
+ic_private void* mem_realloc(alloc_t* mem, void* p, ssize_t newsz) {
+  return mem->realloc(p, to_size_t(newsz));
+}
+
+ic_private void mem_free(alloc_t* mem, const void* p) {
+  mem->free((void*)p);
+}
+
+ic_private char* mem_strdup(alloc_t* mem, const char* s) {
+  if (s==NULL) return NULL;
+  ssize_t n = ic_strlen(s);
+  char* p = mem_malloc_tp_n(mem, char, n+1);
+  if (p == NULL) return NULL;
+  ic_memcpy(p, s, n+1);
+  return p;
+}
+
+ic_private char* mem_strndup(alloc_t* mem, const char* s, ssize_t n) {
+  if (s==NULL || n < 0) return NULL;
+  char* p = mem_malloc_tp_n(mem, char, n+1);
+  if (p == NULL) return NULL;
+  ssize_t i;
+  for (i = 0; i < n && s[i] != 0; i++) {
+    p[i] = s[i];
+  }
+  assert(i <= n);
+  p[i] = 0;
+  return p;
+}
+

extern/isocline/src/common.h

@@ -0,0 +1,187 @@
+/* ----------------------------------------------------------------------------
+  Copyright (c) 2021, Daan Leijen
+  This is free software; you can redistribute it and/or modify it
+  under the terms of the MIT License. A copy of the license can be
+  found in the "LICENSE" file at the root of this distribution.
+-----------------------------------------------------------------------------*/
+
+#pragma once
+#ifndef IC_COMMON_H
+#define IC_COMMON_H
+
+//-------------------------------------------------------------
+// Headers and defines
+//-------------------------------------------------------------
+
+#include <sys/types.h>  // ssize_t
+#include <limits.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <assert.h>
+#include "../include/isocline.h"  // ic_malloc_fun_t, ic_color_t etc.
+
+# ifdef __cplusplus
+#  define ic_extern_c   extern "C"
+# else
+#  define ic_extern_c
+# endif
+
+#if defined(IC_SEPARATE_OBJS)
+#  define ic_public     ic_extern_c 
+# if defined(__GNUC__) // includes clang and icc      
+#  define ic_private    __attribute__((visibility("hidden")))
+# else
+#  define ic_private  
+# endif
+#else
+# define ic_private     static
+# define ic_public      ic_extern_c
+#endif
+
+#define ic_unused(x)    (void)(x)
+
+
+//-------------------------------------------------------------
+// ssize_t
+//-------------------------------------------------------------
+
+#if defined(_MSC_VER)
+typedef intptr_t ssize_t;
+#endif
+
+#define ssizeof(tp)   (ssize_t)(sizeof(tp))
+static inline size_t  to_size_t(ssize_t sz) { return (sz >= 0 ? (size_t)sz : 0); }
+static inline ssize_t to_ssize_t(size_t sz) { return (sz <= SIZE_MAX/2 ? (ssize_t)sz : 0); }
+
+ic_private void    ic_memmove(void* dest, const void* src, ssize_t n);
+ic_private void    ic_memcpy(void* dest, const void* src, ssize_t n);
+ic_private void    ic_memset(void* dest, uint8_t value, ssize_t n);
+ic_private bool    ic_memnmove(void* dest, ssize_t dest_size, const void* src, ssize_t n);
+
+ic_private ssize_t ic_strlen(const char* s);
+ic_private bool    ic_strcpy(char* dest, ssize_t dest_size /* including 0 */, const char* src);
+ic_private bool    ic_strncpy(char* dest, ssize_t dest_size /* including 0 */, const char* src, ssize_t n);
+
+ic_private bool    ic_contains(const char* big, const char* s);
+ic_private bool    ic_icontains(const char* big, const char* s);
+ic_private char    ic_tolower(char c);
+ic_private void    ic_str_tolower(char* s);
+ic_private int     ic_stricmp(const char* s1, const char* s2);
+ic_private int     ic_strnicmp(const char* s1, const char* s2, ssize_t n);
+
+
+
+//---------------------------------------------------------------------
+// Unicode
+//
+// We use "qutf-8" (quite like utf-8) encoding and decoding. 
+// Internally we always use valid utf-8. If we encounter invalid
+// utf-8 bytes (or bytes >= 0x80 from any other encoding) we encode
+// these as special code points in the "raw plane" (0xEE000 - 0xEE0FF).
+// When decoding we are then able to restore such raw bytes as-is.
+// See <https://github.com/koka-lang/koka/blob/master/kklib/include/kklib/string.h>
+//---------------------------------------------------------------------
+
+typedef uint32_t  unicode_t;
+
+ic_private void      unicode_to_qutf8(unicode_t u, uint8_t buf[5]);
+ic_private unicode_t unicode_from_qutf8(const uint8_t* s, ssize_t len, ssize_t* nread); // validating
+
+ic_private unicode_t unicode_from_raw(uint8_t c);
+ic_private bool      unicode_is_raw(unicode_t u, uint8_t* c);
+
+ic_private bool      utf8_is_cont(uint8_t c);
+
+
+//-------------------------------------------------------------
+// Colors
+//-------------------------------------------------------------
+
+// A color is either RGB or an ANSI code.
+// (RGB colors have bit 24 set to distinguish them from the ANSI color palette colors.)
+// (Isocline will automatically convert from RGB on terminals that do not support full colors)
+typedef uint32_t ic_color_t;
+
+// Create a color from a 24-bit color value.
+ic_private ic_color_t ic_rgb(uint32_t hex);
+
+// Create a color from a 8-bit red/green/blue components.
+// The value of each component is capped between 0 and 255.
+ic_private ic_color_t ic_rgbx(ssize_t r, ssize_t g, ssize_t b);
+
+#define IC_COLOR_NONE     (0)
+#define IC_RGB(rgb)       (0x1000000 | (uint32_t)(rgb)) // ic_rgb(rgb)  // define to it can be used as a constant
+
+// ANSI colors.
+// The actual colors used is usually determined by the terminal theme
+// See <https://en.wikipedia.org/wiki/ANSI_escape_code#3-bit_and_4-bit>
+#define IC_ANSI_BLACK     (30)
+#define IC_ANSI_MAROON    (31)
+#define IC_ANSI_GREEN     (32)
+#define IC_ANSI_OLIVE     (33)
+#define IC_ANSI_NAVY      (34)
+#define IC_ANSI_PURPLE    (35)
+#define IC_ANSI_TEAL      (36)
+#define IC_ANSI_SILVER    (37)
+#define IC_ANSI_DEFAULT   (39)
+
+#define IC_ANSI_GRAY      (90)
+#define IC_ANSI_RED       (91)
+#define IC_ANSI_LIME      (92)
+#define IC_ANSI_YELLOW    (93)
+#define IC_ANSI_BLUE      (94)
+#define IC_ANSI_FUCHSIA   (95)
+#define IC_ANSI_AQUA      (96)
+#define IC_ANSI_WHITE     (97)
+
+#define IC_ANSI_DARKGRAY  IC_ANSI_GRAY
+#define IC_ANSI_LIGHTGRAY IC_ANSI_SILVER
+#define IC_ANSI_MAGENTA   IC_ANSI_FUCHSIA
+#define IC_ANSI_CYAN      IC_ANSI_AQUA
+
+
+
+//-------------------------------------------------------------
+// Debug
+//-------------------------------------------------------------
+
+#if defined(IC_NO_DEBUG_MSG) 
+#define debug_msg(fmt,...)   (void)(0)
+#else
+ic_private void debug_msg( const char* fmt, ... );
+#endif
+
+
+//-------------------------------------------------------------
+// Abstract environment
+//-------------------------------------------------------------
+struct ic_env_s;
+typedef struct ic_env_s ic_env_t;
+
+
+//-------------------------------------------------------------
+// Allocation
+//-------------------------------------------------------------
+
+typedef struct alloc_s {
+  ic_malloc_fun_t*  malloc;
+  ic_realloc_fun_t* realloc;
+  ic_free_fun_t*    free;
+} alloc_t;
+
+
+ic_private void* mem_malloc( alloc_t* mem, ssize_t sz );
+ic_private void* mem_zalloc( alloc_t* mem, ssize_t sz );
+ic_private void* mem_realloc( alloc_t* mem, void* p, ssize_t newsz );
+ic_private void  mem_free( alloc_t* mem, const void* p );
+ic_private char* mem_strdup( alloc_t* mem, const char* s);
+ic_private char* mem_strndup( alloc_t* mem, const char* s, ssize_t n);
+
+#define mem_zalloc_tp(mem,tp)        (tp*)mem_zalloc(mem,ssizeof(tp))
+#define mem_malloc_tp_n(mem,tp,n)    (tp*)mem_malloc(mem,(n)*ssizeof(tp))
+#define mem_zalloc_tp_n(mem,tp,n)    (tp*)mem_zalloc(mem,(n)*ssizeof(tp))
+#define mem_realloc_tp(mem,tp,p,n)   (tp*)mem_realloc(mem,p,(n)*ssizeof(tp))
+
+
+#endif // IC_COMMON_H

extern/isocline/src/completers.c

@@ -0,0 +1,675 @@
+/* ----------------------------------------------------------------------------
+  Copyright (c) 2021, Daan Leijen
+  This is free software; you can redistribute it and/or modify it
+  under the terms of the MIT License. A copy of the license can be
+  found in the "LICENSE" file at the root of this distribution.
+-----------------------------------------------------------------------------*/
+#include <string.h>
+#include <stdio.h>
+
+#include "../include/isocline.h"
+#include "common.h"
+#include "env.h"
+#include "stringbuf.h"
+#include "completions.h"
+
+
+
+//-------------------------------------------------------------
+// Word completion 
+//-------------------------------------------------------------
+
+// free variables for word completion
+typedef struct word_closure_s {
+  long                  delete_before_adjust;
+  void*                 prev_env;
+  ic_completion_fun_t*  prev_complete;
+} word_closure_t;
+
+
+// word completion callback
+static bool token_add_completion_ex(ic_env_t* env, void* closure, const char* replacement, const char* display, const char* help, long delete_before, long delete_after) {
+  word_closure_t* wenv = (word_closure_t*)(closure);
+  // call the previous completer with an adjusted delete-before
+  return (*wenv->prev_complete)(env, wenv->prev_env, replacement, display, help, wenv->delete_before_adjust + delete_before, delete_after);
+}
+
+
+ic_public void ic_complete_word(ic_completion_env_t* cenv, const char* prefix, ic_completer_fun_t* fun,
+                                    ic_is_char_class_fun_t* is_word_char) 
+{
+  if (is_word_char == NULL) is_word_char = &ic_char_is_nonseparator;
+  
+  ssize_t len = ic_strlen(prefix);
+  ssize_t pos = len; // will be start of the 'word' (excluding a potential start quote)
+  while (pos > 0) {
+    // go back one code point
+    ssize_t ofs = str_prev_ofs(prefix, pos, NULL);
+    if (ofs <= 0) break;
+    if (!(*is_word_char)(prefix + (pos - ofs), (long)ofs)) { 
+      break;
+    }
+    pos -= ofs;
+  }
+  if (pos < 0) { pos = 0; }
+  
+  // stop if empty word
+  // if (len == pos) return;
+  
+  // set up the closure
+  word_closure_t wenv;
+  wenv.delete_before_adjust = (long)(len - pos);
+  wenv.prev_complete = cenv->complete;
+  wenv.prev_env = cenv->env;
+  cenv->complete = &token_add_completion_ex;
+  cenv->closure = &wenv;
+
+  // and call the user completion routine
+  (*fun)(cenv, prefix + pos);
+
+  // restore the original environment
+  cenv->complete = wenv.prev_complete;
+  cenv->closure = wenv.prev_env;
+}
+
+
+//-------------------------------------------------------------
+// Quoted word completion (with escape characters)
+//-------------------------------------------------------------
+
+// free variables for word completion
+typedef struct qword_closure_s {
+  char         escape_char;
+  char         quote;
+  long         delete_before_adjust;
+  stringbuf_t* sbuf;
+  void*        prev_env;
+  ic_is_char_class_fun_t* is_word_char;
+  ic_completion_fun_t*    prev_complete;
+} qword_closure_t;
+
+
+// word completion callback
+static bool qword_add_completion_ex(ic_env_t* env, void* closure, const char* replacement, const char* display, const char* help, 
+                                       long delete_before, long delete_after) {
+  qword_closure_t* wenv = (qword_closure_t*)(closure);
+  sbuf_replace( wenv->sbuf, replacement );   
+  if (wenv->quote != 0) {
+    // add end quote
+    sbuf_append_char( wenv->sbuf, wenv->quote);
+  }
+  else {
+    // escape non-word characters if it was not quoted
+    ssize_t pos = 0;
+    ssize_t next;
+    while ( (next = sbuf_next_ofs(wenv->sbuf, pos, NULL)) > 0 ) 
+    {
+      if (!(*wenv->is_word_char)(sbuf_string(wenv->sbuf) + pos, (long)next)) { // strchr(wenv->non_word_char, sbuf_char_at( wenv->sbuf, pos )) != NULL) {
+        sbuf_insert_char_at( wenv->sbuf, wenv->escape_char, pos);
+        pos++;
+      }
+      pos += next;
+    }
+  }
+  // and call the previous completion function
+  return (*wenv->prev_complete)( env, wenv->prev_env, sbuf_string(wenv->sbuf), display, help, wenv->delete_before_adjust + delete_before, delete_after );  
+}
+
+
+ic_public void ic_complete_qword( ic_completion_env_t* cenv, const char* prefix, ic_completer_fun_t* fun, ic_is_char_class_fun_t* is_word_char ) {
+  ic_complete_qword_ex( cenv, prefix, fun, is_word_char, '\\', NULL);
+}
+
+
+ic_public void ic_complete_qword_ex( ic_completion_env_t* cenv, const char* prefix, ic_completer_fun_t* fun, 
+                                        ic_is_char_class_fun_t* is_word_char, char escape_char, const char* quote_chars ) {
+  if (is_word_char == NULL) is_word_char = &ic_char_is_nonseparator ;  
+  if (quote_chars == NULL) quote_chars = "'\"";
+
+  ssize_t len = ic_strlen(prefix);
+  ssize_t pos; // will be start of the 'word' (excluding a potential start quote)
+  char quote = 0;
+  ssize_t quote_len = 0;
+  
+  // 1. look for a starting quote
+  if (quote_chars[0] != 0) {
+    // we go forward and count all quotes; if it is uneven, we need to complete quoted.
+    ssize_t qpos_open = -1;
+    ssize_t qpos_close = -1;
+    ssize_t qcount = 0;
+    pos = 0; 
+    while(pos < len) {
+      if (prefix[pos] == escape_char && prefix[pos+1] != 0 && 
+           !(*is_word_char)(prefix + pos + 1, 1)) // strchr(non_word_char, prefix[pos+1]) != NULL
+      {       
+        pos++; // skip escape and next char
+      }
+      else if (qcount % 2 == 0 && strchr(quote_chars, prefix[pos]) != NULL) {
+        // open quote 
+        qpos_open = pos;
+        quote = prefix[pos];
+        qcount++;
+      }
+      else if (qcount % 2 == 1 && prefix[pos] == quote) {
+        // close quote
+        qpos_close = pos;
+        qcount++;
+      }
+      else if (!(*is_word_char)(prefix + pos, 1)) { //  strchr(non_word_char, prefix[pos]) != NULL) {
+        qpos_close = -1;
+      }
+      ssize_t ofs = str_next_ofs( prefix, len, pos, NULL );
+      if (ofs <= 0) break;
+      pos += ofs;
+    }    
+    if ((qcount % 2 == 0 && qpos_close >= 0) || // if the last quote is only followed by word chars, we still complete it
+        (qcount % 2 == 1))                     // opening quote found
+    {
+      quote_len = (len - qpos_open - 1);
+      pos = qpos_open + 1;  // pos points to the word start just after the quote.
+    }
+    else {
+      quote = 0;
+    }
+  }
+
+  // 2. if we did not find a quoted word, look for non-word-chars
+  if (quote == 0) {
+    pos = len;
+    while(pos > 0) {
+      // go back one code point
+      ssize_t ofs = str_prev_ofs(prefix, pos, NULL );
+      if (ofs <= 0) break;
+      if (!(*is_word_char)(prefix + (pos - ofs), (long)ofs)) { // strchr(non_word_char, prefix[pos - ofs]) != NULL) {
+        // non word char, break if it is not escaped
+        if (pos <= ofs || prefix[pos - ofs - 1] != escape_char) break; 
+        // otherwise go on
+        pos--; // skip escaped char
+      }
+      pos -= ofs;
+    }
+  }
+
+  // stop if empty word
+  // if (len == pos) return;
+
+  // allocate new unescaped word prefix
+  char* word = mem_strndup( cenv->env->mem, prefix + pos, (quote==0 ? len - pos : quote_len));
+  if (word == NULL) return;
+
+  if (quote == 0) {
+    // unescape prefix
+    ssize_t wlen = len - pos;
+    ssize_t wpos = 0;
+    while (wpos < wlen) {
+      ssize_t ofs = str_next_ofs(word, wlen, wpos, NULL);
+      if (ofs <= 0) break;
+      if (word[wpos] == escape_char && word[wpos+1] != 0 &&
+           !(*is_word_char)(word + wpos + 1, (long)ofs)) // strchr(non_word_char, word[wpos+1]) != NULL) {
+      {
+        ic_memmove(word + wpos, word + wpos + 1, wlen - wpos /* including 0 */);
+      }
+      wpos += ofs;
+    }
+  }
+  #ifdef _WIN32
+  else {
+    // remove inner quote: "c:\Program Files\"Win
+    ssize_t wlen = len - pos;
+    ssize_t wpos = 0;
+    while (wpos < wlen) {
+      ssize_t ofs = str_next_ofs(word, wlen, wpos, NULL);
+      if (ofs <= 0) break;
+      if (word[wpos] == escape_char && word[wpos+1] == quote) {
+        word[wpos+1] = escape_char;
+        ic_memmove(word + wpos, word + wpos + 1, wlen - wpos /* including 0 */);
+      }
+      wpos += ofs;
+    }
+  }
+  #endif
+
+  // set up the closure
+  qword_closure_t wenv;
+  wenv.quote          = quote;
+  wenv.is_word_char   = is_word_char;
+  wenv.escape_char    = escape_char;
+  wenv.delete_before_adjust = (long)(len - pos);
+  wenv.prev_complete  = cenv->complete;
+  wenv.prev_env       =  cenv->env;
+  wenv.sbuf = sbuf_new(cenv->env->mem);
+  if (wenv.sbuf == NULL) { mem_free(cenv->env->mem, word); return; }
+  cenv->complete = &qword_add_completion_ex;
+  cenv->closure = &wenv;
+
+  // and call the user completion routine
+  (*fun)( cenv, word );
+
+  // restore the original environment
+  cenv->complete = wenv.prev_complete;
+  cenv->closure = wenv.prev_env;
+
+  sbuf_free(wenv.sbuf);
+  mem_free(cenv->env->mem, word);  
+}
+
+
+
+
+//-------------------------------------------------------------
+// Complete file names
+// Listing files
+//-------------------------------------------------------------
+#include <stdlib.h>
+
+typedef enum file_type_e {
+  // must follow BSD style LSCOLORS order
+  FT_DEFAULT = 0,
+  FT_DIR,
+  FT_SYM,
+  FT_SOCK,
+  FT_PIPE,
+  FT_BLOCK,
+  FT_CHAR,
+  FT_SETUID,
+  FT_SETGID,
+  FT_DIR_OW_STICKY,
+  FT_DIR_OW,
+  FT_DIR_STICKY,
+  FT_EXE,
+  FT_LAST
+} file_type_t;
+
+static int         cli_color; // 1 enabled, 0 not initialized, -1 disabled
+static const char* lscolors  = "exfxcxdxbxegedabagacad";  // default BSD setting
+static const char* ls_colors;
+static const char* ls_colors_names[] = { "no=","di=","ln=","so=","pi=","bd=","cd=","su=","sg=","tw=","ow=","st=","ex=", NULL };
+
+static bool ls_colors_init(void) {
+  if (cli_color != 0) return (cli_color >= 1);
+  // colors enabled?
+  const char* s = getenv("CLICOLOR");
+  if (s==NULL || (strcmp(s, "1")!=0 && strcmp(s, "") != 0)) {
+    cli_color = -1;
+    return false;
+  }
+  cli_color = 1;
+  s = getenv("LS_COLORS");
+  if (s != NULL) { ls_colors = s;  }
+  s = getenv("LSCOLORS");
+  if (s != NULL) { lscolors = s; }  
+  return true;
+}
+
+static bool ls_valid_esc(ssize_t c) {
+  return ((c==0 || c==1 || c==4 || c==7 || c==22 || c==24  || c==27) ||
+    (c >= 30 && c <= 37) || (c >= 40 && c <= 47) ||
+    (c >= 90 && c <= 97) || (c >= 100 && c <= 107));
+}
+
+static bool ls_colors_from_key(stringbuf_t* sb, const char* key) {
+  // find key
+  ssize_t keylen = ic_strlen(key);
+  if (keylen <= 0) return false;
+  const char* p = strstr(ls_colors, key);
+  if (p == NULL) return false;
+  p += keylen;
+  if (key[keylen-1] != '=') {
+    if (*p != '=') return false;
+    p++;
+  }
+  ssize_t len = 0;
+  while (p[len] != 0 && p[len] != ':') {
+    len++;
+  }
+  if (len <= 0) return false;
+  sbuf_append(sb, "[ansi-sgr=\"" );
+  sbuf_append_n(sb, p, len );
+  sbuf_append(sb, "\"]");
+  return true;
+}
+
+static int ls_colors_from_char(char c) {
+  if (c >= 'a' && c <= 'h')      { return (c - 'a'); }
+  else if (c >= 'A' && c <= 'H') { return (c - 'A') + 8; }
+  else if (c == 'x')             { return 256; }
+  else return 256; // default
+}
+
+static bool ls_colors_append(stringbuf_t* sb, file_type_t ft, const char* ext) {
+  if (!ls_colors_init()) return false;
+  if (ls_colors != NULL) {
+    // GNU style
+    if (ft == FT_DEFAULT && ext != NULL) {
+      // first try extension match
+      if (ls_colors_from_key(sb, ext)) return true;
+    }
+    if (ft >= FT_DEFAULT && ft < FT_LAST) {
+      // then a filetype match
+      const char* key = ls_colors_names[ft];
+      if (ls_colors_from_key(sb, key)) return true;
+    }    
+  }
+  else if (lscolors != NULL) {
+    // BSD style
+    char fg = 'x';
+    char bg = 'x';
+    if (ic_strlen(lscolors) > (2*(ssize_t)ft)+1) {
+      fg = lscolors[2*ft];
+      bg = lscolors[2*ft + 1];
+    }
+    sbuf_appendf(sb, "[ansi-color=%d ansi-bgcolor=%d]", ls_colors_from_char(fg), ls_colors_from_char(bg) );
+    return true;
+  }
+  return false;
+}
+
+static void ls_colorize(bool no_lscolor, stringbuf_t* sb, file_type_t ft, const char* name, const char* ext, char dirsep) {
+  bool close = (no_lscolor ? false : ls_colors_append( sb, ft, ext));
+  sbuf_append(sb, "[!pre]" );
+  sbuf_append(sb, name);
+  if (dirsep != 0) sbuf_append_char(sb, dirsep);
+  sbuf_append(sb,"[/pre]" );
+  if (close) { sbuf_append(sb, "[/]"); }
+}
+
+#if defined(_WIN32)
+#include <io.h>
+#include <sys/stat.h>
+
+static bool os_is_dir(const char* cpath) {
+  struct _stat64 st = { 0 };
+  _stat64(cpath, &st);
+  return ((st.st_mode & _S_IFDIR) != 0);
+}
+
+static file_type_t os_get_filetype(const char* cpath) {
+  struct _stat64 st = { 0 };
+  _stat64(cpath, &st);
+  if (((st.st_mode) & _S_IFDIR) != 0) return FT_DIR;
+  if (((st.st_mode) & _S_IFCHR) != 0) return FT_CHAR;
+  if (((st.st_mode) & _S_IFIFO) != 0) return FT_PIPE;
+  if (((st.st_mode) & _S_IEXEC) != 0) return FT_EXE;
+  return FT_DEFAULT;
+}
+
+
+#define dir_cursor intptr_t
+#define dir_entry  struct __finddata64_t
+
+static bool os_findfirst(alloc_t* mem, const char* path, dir_cursor* d, dir_entry* entry) {
+  stringbuf_t* spath = sbuf_new(mem);
+  if (spath == NULL) return false;
+  sbuf_append(spath, path);
+  sbuf_append(spath, "\\*");
+  *d = _findfirsti64(sbuf_string(spath), entry);
+  mem_free(mem,spath);
+  return (*d != -1);
+}
+
+static bool os_findnext(dir_cursor d, dir_entry* entry) {
+  return (_findnexti64(d, entry) == 0);  
+}
+
+static void os_findclose(dir_cursor d) {
+  _findclose(d);
+}
+
+static const char* os_direntry_name(dir_entry* entry) {
+  return entry->name;  
+}
+
+static bool os_path_is_absolute( const char* path ) {
+  if (path != NULL && path[0] != 0 && path[1] == ':' && (path[2] == '\\' || path[2] == '/' || path[2] == 0)) {
+    char drive = path[0];
+    return ((drive >= 'A' && drive <= 'Z') || (drive >= 'a' && drive <= 'z'));
+  }
+  else return false;
+}
+
+ic_private char ic_dirsep(void) {
+  return '\\';
+}
+#else
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <dirent.h>
+#include <errno.h>
+
+static bool os_is_dir(const char* cpath) {
+  struct stat st;
+  memset(&st, 0, sizeof(st));
+  stat(cpath, &st);
+  return (S_ISDIR(st.st_mode));
+}
+
+static file_type_t os_get_filetype(const char* cpath) {
+  struct stat st;
+  memset(&st, 0, sizeof(st));
+  lstat(cpath, &st);
+  switch ((st.st_mode)&S_IFMT) {
+    case S_IFSOCK: return FT_SOCK;
+    case S_IFLNK: {
+      return FT_SYM;
+    }
+    case S_IFIFO:  return FT_PIPE;
+    case S_IFCHR:  return FT_CHAR;
+    case S_IFBLK:  return FT_BLOCK;
+    case S_IFDIR: {
+      if ((st.st_mode & S_ISUID) != 0) return FT_SETUID;
+      if ((st.st_mode & S_ISGID) != 0) return FT_SETGID;
+      if ((st.st_mode & S_IWGRP) != 0 && (st.st_mode & S_ISVTX) != 0) return FT_DIR_OW_STICKY;
+      if ((st.st_mode & S_IWGRP)) return FT_DIR_OW;
+      if ((st.st_mode & S_ISVTX)) return FT_DIR_STICKY;
+      return FT_DIR;
+    }
+    case S_IFREG:
+    default: {
+      if ((st.st_mode & S_IXUSR) != 0) return FT_EXE;
+      return FT_DEFAULT;
+    }
+  }  
+}
+
+
+#define dir_cursor DIR*
+#define dir_entry  struct dirent*
+
+static bool os_findnext(dir_cursor d, dir_entry* entry) {
+  *entry = readdir(d);
+  return (*entry != NULL);
+}
+
+static bool os_findfirst(alloc_t* mem, const char* cpath, dir_cursor* d, dir_entry* entry) {
+  ic_unused(mem);
+  *d = opendir(cpath);
+  if (*d == NULL) {
+    return false;
+  }
+  else {
+    return os_findnext(*d, entry);
+  }
+}
+
+static void os_findclose(dir_cursor d) {
+  closedir(d);
+}
+
+static const char* os_direntry_name(dir_entry* entry) {
+  return (*entry)->d_name;  
+}
+
+static bool os_path_is_absolute( const char* path ) {
+  return (path != NULL && path[0] == '/');
+}
+
+ic_private char ic_dirsep(void) {
+  return '/';
+}
+#endif
+
+
+
+//-------------------------------------------------------------
+// File completion 
+//-------------------------------------------------------------
+
+static bool ends_with_n(const char* name, ssize_t name_len, const char* ending, ssize_t len) {
+  if (name_len < len) return false;
+  if (ending == NULL || len <= 0) return true;
+  for (ssize_t i = 1; i <= len; i++) {
+    char c1 = name[name_len - i];
+    char c2 = ending[len - i];
+    #ifdef _WIN32
+    if (ic_tolower(c1) != ic_tolower(c2)) return false;
+    #else
+    if (c1 != c2) return false;
+    #endif
+  }
+  return true;
+}
+
+static bool match_extension(const char* name, const char* extensions) {
+  if (extensions == NULL || extensions[0] == 0) return true;
+  if (name == NULL) return false;
+  ssize_t name_len = ic_strlen(name);
+  ssize_t len = ic_strlen(extensions);
+  ssize_t cur = 0;  
+  //debug_msg("match extensions: %s ~ %s", name, extensions);
+  for (ssize_t end = 0; end <= len; end++) {
+    if (extensions[end] == ';' || extensions[end] == 0) {
+      if (ends_with_n(name, name_len, extensions+cur, (end - cur))) {
+        return true;
+      }
+      cur = end+1;
+    }
+  }
+  return false;
+}
+
+static bool filename_complete_indir( ic_completion_env_t* cenv, stringbuf_t* dir, 
+                                      stringbuf_t* dir_prefix, stringbuf_t* display,
+                                       const char* base_prefix, 
+                                        char dir_sep, const char* extensions ) 
+{
+  dir_cursor d = 0;
+  dir_entry entry;
+  bool cont = true;
+  if (os_findfirst(cenv->env->mem, sbuf_string(dir), &d, &entry)) {
+    do {
+      const char* name = os_direntry_name(&entry);
+      if (name != NULL && strcmp(name, ".") != 0 && strcmp(name, "..") != 0 && 
+          ic_istarts_with(name, base_prefix))
+      {
+        // possible match, first check if it is a directory
+        file_type_t ft;
+        bool isdir;
+        const ssize_t plen = sbuf_len(dir_prefix);
+        sbuf_append(dir_prefix, name);
+        { // check directory and potentially add a dirsep to the dir_prefix
+          const ssize_t dlen = sbuf_len(dir);
+          sbuf_append_char(dir,ic_dirsep());
+          sbuf_append(dir,name);
+          ft = os_get_filetype(sbuf_string(dir));
+          isdir = os_is_dir(sbuf_string(dir));
+          if (isdir && dir_sep != 0) {
+            sbuf_append_char(dir_prefix,dir_sep); 
+          }
+          sbuf_delete_from(dir,dlen);  // restore dir
+        }
+        if (isdir || match_extension(name, extensions)) {
+          // add completion
+          sbuf_clear(display);
+          ls_colorize(cenv->env->no_lscolors, display, ft, name, NULL, (isdir ? dir_sep : 0));
+          cont = ic_add_completion_ex(cenv, sbuf_string(dir_prefix), sbuf_string(display), NULL);
+        }
+        sbuf_delete_from( dir_prefix, plen ); // restore dir_prefix
+      }
+    } while (cont && os_findnext(d, &entry));
+    os_findclose(d);
+  }
+  return cont;
+}
+
+typedef struct filename_closure_s {
+  const char* roots;
+  const char* extensions;
+  char        dir_sep;
+} filename_closure_t;
+
+static void filename_completer( ic_completion_env_t* cenv, const char* prefix ) {
+  if (prefix == NULL) return;
+  filename_closure_t* fclosure = (filename_closure_t*)cenv->arg;  
+  stringbuf_t* root_dir   = sbuf_new(cenv->env->mem);
+  stringbuf_t* dir_prefix = sbuf_new(cenv->env->mem);
+  stringbuf_t* display    = sbuf_new(cenv->env->mem);  
+  if (root_dir!=NULL && dir_prefix != NULL && display != NULL) 
+  {
+    // split prefix in dir_prefix / base.
+    const char* base = strrchr(prefix,'/');
+    #ifdef _WIN32
+    const char* base2 = strrchr(prefix,'\\');
+    if (base == NULL || base2 > base) base = base2;
+    #endif
+    if (base != NULL) {
+      base++; 
+      sbuf_append_n(dir_prefix, prefix, base - prefix ); // includes dir separator
+    }
+
+    // absolute path
+    if (os_path_is_absolute(prefix)) {
+      // do not use roots but try to complete directly
+      if (base != NULL) {
+        sbuf_append_n( root_dir, prefix, (base - prefix));  // include dir separator
+      }
+      filename_complete_indir( cenv, root_dir, dir_prefix, display,  
+                                (base != NULL ? base : prefix), 
+                                 fclosure->dir_sep, fclosure->extensions );   
+    }
+    else {
+      // relative path, complete with respect to every root.
+      const char* next;
+      const char* root = fclosure->roots;
+      while ( root != NULL ) {
+        // create full root in `root_dir`
+        sbuf_clear(root_dir);
+        next = strchr(root,';');
+        if (next == NULL) {
+          sbuf_append( root_dir, root );
+          root = NULL;
+        }
+        else {
+          sbuf_append_n( root_dir, root, next - root );
+          root = next + 1;
+        }      
+        sbuf_append_char( root_dir, ic_dirsep());
+          
+        // add the dir_prefix to the root
+        if (base != NULL) {
+          sbuf_append_n( root_dir, prefix, (base - prefix) - 1);
+        }
+
+        // and complete in this directory    
+        filename_complete_indir( cenv, root_dir, dir_prefix, display,
+                                  (base != NULL ? base : prefix), 
+                                   fclosure->dir_sep, fclosure->extensions);
+      }
+    }
+  }
+  sbuf_free(display);
+  sbuf_free(root_dir);
+  sbuf_free(dir_prefix);
+}
+
+ic_public void ic_complete_filename( ic_completion_env_t* cenv, const char* prefix, char dir_sep, const char* roots, const char* extensions ) {
+  if (roots == NULL) roots = ".";
+  if (extensions == NULL) extensions = "";
+  if (dir_sep == 0) dir_sep = ic_dirsep();
+  filename_closure_t fclosure;
+  fclosure.dir_sep = dir_sep;
+  fclosure.roots = roots; 
+  fclosure.extensions = extensions;
+  cenv->arg = &fclosure;
+  ic_complete_qword_ex( cenv, prefix, &filename_completer, &ic_char_is_filename_letter, '\\', "'\"");  
+}

extern/isocline/src/completions.c

@@ -0,0 +1,326 @@
+/* ----------------------------------------------------------------------------
+  Copyright (c) 2021, Daan Leijen
+  This is free software; you can redistribute it and/or modify it
+  under the terms of the MIT License. A copy of the license can be
+  found in the "LICENSE" file at the root of this distribution.
+-----------------------------------------------------------------------------*/
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "../include/isocline.h"
+#include "common.h"
+#include "env.h"
+#include "stringbuf.h"
+#include "completions.h"
+
+
+//-------------------------------------------------------------
+// Completions
+//-------------------------------------------------------------
+
+typedef struct completion_s {
+  const char* replacement;
+  const char* display;
+  const char* help;
+  ssize_t     delete_before;
+  ssize_t     delete_after;
+} completion_t;
+
+struct completions_s {
+  ic_completer_fun_t* completer;
+  void* completer_arg;
+  ssize_t completer_max;
+  ssize_t count;
+  ssize_t len;
+  completion_t* elems;
+  alloc_t* mem;
+};
+
+static void default_filename_completer( ic_completion_env_t* cenv, const char* prefix );
+
+ic_private completions_t* completions_new(alloc_t* mem) {
+  completions_t* cms = mem_zalloc_tp(mem, completions_t);
+  if (cms == NULL) return NULL;
+  cms->mem = mem;
+  cms->completer = &default_filename_completer;
+  return cms;
+}
+
+ic_private void completions_free(completions_t* cms) {
+  if (cms == NULL) return;
+  completions_clear(cms);  
+  if (cms->elems != NULL) {
+    mem_free(cms->mem, cms->elems);
+    cms->elems = NULL;
+    cms->count = 0;
+    cms->len = 0;
+  }
+  mem_free(cms->mem, cms); // free ourselves
+}
+
+
+ic_private void completions_clear(completions_t* cms) {  
+  while (cms->count > 0) {
+    completion_t* cm = cms->elems + cms->count - 1;
+    mem_free( cms->mem, cm->display);
+    mem_free( cms->mem, cm->replacement);
+    mem_free( cms->mem, cm->help);
+    memset(cm,0,sizeof(*cm));
+    cms->count--;    
+  }
+}
+
+static void completions_push(completions_t* cms, const char* replacement, const char* display, const char* help, ssize_t delete_before, ssize_t delete_after) 
+{
+  if (cms->count >= cms->len) {
+    ssize_t newlen = (cms->len <= 0 ? 32 : cms->len*2);
+    completion_t* newelems = mem_realloc_tp(cms->mem, completion_t, cms->elems, newlen );
+    if (newelems == NULL) return;
+    cms->elems = newelems;
+    cms->len   = newlen;
+  }
+  assert(cms->count < cms->len);
+  completion_t* cm  = cms->elems + cms->count;
+  cm->replacement   = mem_strdup(cms->mem,replacement);
+  cm->display       = mem_strdup(cms->mem,display);
+  cm->help          = mem_strdup(cms->mem,help);
+  cm->delete_before = delete_before;
+  cm->delete_after  = delete_after;
+  cms->count++;
+}
+
+ic_private ssize_t completions_count(completions_t* cms) {
+  return cms->count;
+}
+
+static bool completions_contains(completions_t* cms, const char* replacement) {
+  for( ssize_t i = 0; i < cms->count; i++ ) {
+    const completion_t* c = cms->elems + i;
+    if (strcmp(replacement,c->replacement) == 0) { return true; }
+  }
+  return false;
+} 
+
+ic_private bool completions_add(completions_t* cms, const char* replacement, const char* display, const char* help, ssize_t delete_before, ssize_t delete_after) {
+  if (cms->completer_max <= 0) return false;
+  cms->completer_max--;
+  //debug_msg("completion: add: %d,%d, %s\n", delete_before, delete_after, replacement);
+  if (!completions_contains(cms,replacement)) {
+    completions_push(cms, replacement, display, help, delete_before, delete_after);
+  }
+  return true;
+}
+
+static completion_t* completions_get(completions_t* cms, ssize_t index) {
+  if (index < 0 || cms->count <= 0 || index >= cms->count) return NULL;
+  return &cms->elems[index];
+}
+
+ic_private const char* completions_get_display( completions_t* cms, ssize_t index, const char** help ) {
+  if (help != NULL) { *help = NULL;  }
+  completion_t* cm = completions_get(cms, index);
+  if (cm == NULL) return NULL;
+  if (help != NULL) { *help = cm->help; }
+  return (cm->display != NULL ? cm->display : cm->replacement);
+}
+
+ic_private const char* completions_get_help( completions_t* cms, ssize_t index ) {
+  completion_t* cm = completions_get(cms, index);
+  if (cm == NULL) return NULL;
+  return cm->help;
+}
+
+ic_private const char* completions_get_hint(completions_t* cms, ssize_t index, const char** help) {
+  if (help != NULL) { *help = NULL; }
+  completion_t* cm = completions_get(cms, index);
+  if (cm == NULL) return NULL;
+  ssize_t len = ic_strlen(cm->replacement);
+  if (len < cm->delete_before) return NULL;
+  const char* hint = (cm->replacement + cm->delete_before);
+  if (*hint == 0 || utf8_is_cont((uint8_t)(*hint))) return NULL;  // utf8 boundary?
+  if (help != NULL) { *help = cm->help; }
+  return hint;
+}
+
+ic_private void completions_set_completer(completions_t* cms, ic_completer_fun_t* completer, void* arg) {
+  cms->completer = completer;
+  cms->completer_arg = arg;
+}
+
+ic_private void completions_get_completer(completions_t* cms, ic_completer_fun_t** completer, void** arg) {
+  *completer = cms->completer;
+  *arg = cms->completer_arg;
+}
+
+
+ic_public void* ic_completion_arg( const ic_completion_env_t* cenv ) {
+  return (cenv == NULL ? NULL : cenv->env->completions->completer_arg);
+}
+
+ic_public bool ic_has_completions( const ic_completion_env_t* cenv ) {
+  return (cenv == NULL ? false : cenv->env->completions->count > 0);
+}
+
+ic_public bool ic_stop_completing( const ic_completion_env_t* cenv) {
+  return (cenv == NULL ? true : cenv->env->completions->completer_max <= 0);
+}
+
+
+static ssize_t completion_apply( completion_t* cm, stringbuf_t* sbuf, ssize_t pos ) {
+  if (cm == NULL) return -1;  
+  debug_msg( "completion: apply: %s at %zd\n", cm->replacement, pos);
+  ssize_t start = pos - cm->delete_before;
+  if (start < 0) start = 0;
+  ssize_t n = cm->delete_before + cm->delete_after;
+  if (ic_strlen(cm->replacement) == n && strncmp(sbuf_string_at(sbuf,start), cm->replacement, to_size_t(n)) == 0) {
+    // no changes
+    return -1;
+  }
+  else {
+    sbuf_delete_from_to( sbuf, start, pos + cm->delete_after );
+    return sbuf_insert_at(sbuf, cm->replacement, start); 
+  }
+}
+
+ic_private ssize_t completions_apply( completions_t* cms, ssize_t index, stringbuf_t* sbuf, ssize_t pos ) {
+  completion_t* cm = completions_get(cms, index);
+  return completion_apply( cm, sbuf, pos );
+}
+
+
+static int completion_compare(const void* p1, const void* p2) {
+  if (p1 == NULL || p2 == NULL) return 0;
+  const completion_t* cm1 = (const completion_t*)p1;
+  const completion_t* cm2 = (const completion_t*)p2;  
+  return ic_stricmp(cm1->replacement, cm2->replacement);
+}
+
+ic_private void completions_sort(completions_t* cms) {
+  if (cms->count <= 0) return;
+  qsort(cms->elems, to_size_t(cms->count), sizeof(cms->elems[0]), &completion_compare);
+}
+
+#define IC_MAX_PREFIX  (256)
+
+// find longest common prefix and complete with that.
+ic_private ssize_t completions_apply_longest_prefix(completions_t* cms, stringbuf_t* sbuf, ssize_t pos) {
+  if (cms->count <= 1) {
+    return completions_apply(cms,0,sbuf,pos);
+  }
+
+  // set initial prefix to the first entry
+  completion_t* cm = completions_get(cms, 0);
+  if (cm == NULL) return -1;
+
+  char prefix[IC_MAX_PREFIX+1];
+  ssize_t delete_before = cm->delete_before;
+  ic_strncpy( prefix, IC_MAX_PREFIX+1, cm->replacement, IC_MAX_PREFIX );
+  prefix[IC_MAX_PREFIX] = 0;
+  
+  // and visit all others to find the longest common prefix
+  for(ssize_t i = 1; i < cms->count; i++) {
+    cm = completions_get(cms,i);
+    if (cm->delete_before != delete_before) {  // deletions must match delete_before
+      prefix[0] = 0;
+      break;
+    }
+    // check if it is still a prefix
+    const char* r = cm->replacement;    
+    ssize_t j;
+    for(j = 0; prefix[j] != 0 && r[j] != 0; j++) {
+      if (prefix[j] != r[j]) break;
+    }
+    prefix[j] = 0;
+    if (j <= 0) break;
+  }
+
+  // check the length
+  ssize_t len = ic_strlen(prefix);
+  if (len <= 0 || len < delete_before) return -1;
+
+  // we found a prefix :-)
+  completion_t cprefix;
+  memset(&cprefix,0,sizeof(cprefix));
+  cprefix.delete_before = delete_before;
+  cprefix.replacement   = prefix;
+  ssize_t newpos = completion_apply( &cprefix, sbuf, pos);
+  if (newpos < 0) return newpos;  
+
+  // adjust all delete_before for the new replacement
+  for( ssize_t i = 0; i < cms->count; i++) {
+    cm = completions_get(cms,i);
+    cm->delete_before = len;
+  }
+
+  return newpos;
+}
+
+
+//-------------------------------------------------------------
+// Completer functions
+//-------------------------------------------------------------
+
+ic_public bool ic_add_completions(ic_completion_env_t* cenv, const char* prefix, const char** completions) {
+  for (const char** pc = completions; *pc != NULL; pc++) {
+    if (ic_istarts_with(*pc, prefix)) {
+      if (!ic_add_completion_ex(cenv, *pc, NULL, NULL)) return false;
+    }
+  }
+  return true;
+}
+
+ic_public bool ic_add_completion(ic_completion_env_t* cenv, const char* replacement) {
+  return ic_add_completion_ex(cenv, replacement, NULL, NULL);
+}
+
+ic_public bool ic_add_completion_ex( ic_completion_env_t* cenv, const char* replacement, const char* display, const char* help ) {
+  return ic_add_completion_prim(cenv,replacement,display,help,0,0);
+}
+
+ic_public bool ic_add_completion_prim(ic_completion_env_t* cenv, const char* replacement, const char* display, const char* help, long delete_before, long delete_after) {
+  return (*cenv->complete)(cenv->env, cenv->closure, replacement, display, help, delete_before, delete_after );
+}
+
+static bool prim_add_completion(ic_env_t* env, void* funenv, const char* replacement, const char* display, const char* help, long delete_before, long delete_after) {
+  ic_unused(funenv);
+  return completions_add(env->completions, replacement, display, help, delete_before, delete_after);
+}
+
+ic_public void ic_set_default_completer(ic_completer_fun_t* completer, void* arg) {
+  ic_env_t* env = ic_get_env(); if (env == NULL) return;
+  completions_set_completer(env->completions, completer, arg);
+}
+
+ic_private ssize_t completions_generate(struct ic_env_s* env, completions_t* cms, const char* input, ssize_t pos, ssize_t max) {
+  completions_clear(cms);
+  if (cms->completer == NULL || input == NULL || ic_strlen(input) < pos) return 0;
+
+  // set up env
+  ic_completion_env_t cenv;
+  cenv.env = env;
+  cenv.input = input,
+  cenv.cursor = (long)pos;
+  cenv.arg = cms->completer_arg;
+  cenv.complete = &prim_add_completion;
+  cenv.closure  = NULL;
+  const char* prefix = mem_strndup(cms->mem, input, pos);
+  cms->completer_max = max;
+  
+  // and complete
+  cms->completer(&cenv,prefix);
+
+  // restore
+  mem_free(cms->mem,prefix);
+  return completions_count(cms);
+}
+
+// The default completer is no completion is set
+static void default_filename_completer( ic_completion_env_t* cenv, const char* prefix ) {
+  #ifdef _WIN32
+  const char sep = '\\';
+  #else
+  const char sep = '/';
+  #endif
+  ic_complete_filename( cenv, prefix, sep, ".", NULL);
+}

extern/isocline/src/completions.h

@@ -0,0 +1,52 @@
+/* ----------------------------------------------------------------------------
+  Copyright (c) 2021, Daan Leijen
+  This is free software; you can redistribute it and/or modify it
+  under the terms of the MIT License. A copy of the license can be
+  found in the "LICENSE" file at the root of this distribution.
+-----------------------------------------------------------------------------*/
+#pragma once
+#ifndef IC_COMPLETIONS_H
+#define IC_COMPLETIONS_H
+
+#include "common.h"
+#include "stringbuf.h"
+
+
+//-------------------------------------------------------------
+// Completions
+//-------------------------------------------------------------
+#define IC_MAX_COMPLETIONS_TO_SHOW  (1000)
+#define IC_MAX_COMPLETIONS_TO_TRY   (IC_MAX_COMPLETIONS_TO_SHOW/4)
+
+typedef struct completions_s completions_t;
+
+ic_private completions_t* completions_new(alloc_t* mem);
+ic_private void        completions_free(completions_t* cms);
+ic_private void        completions_clear(completions_t* cms);
+ic_private bool        completions_add(completions_t* cms , const char* replacement, const char* display, const char* help, ssize_t delete_before, ssize_t delete_after);
+ic_private ssize_t     completions_count(completions_t* cms);
+ic_private ssize_t     completions_generate(struct ic_env_s* env, completions_t* cms , const char* input, ssize_t pos, ssize_t max);
+ic_private void        completions_sort(completions_t* cms);
+ic_private void        completions_set_completer(completions_t* cms, ic_completer_fun_t* completer, void* arg);
+ic_private const char* completions_get_display(completions_t* cms , ssize_t index, const char** help);
+ic_private const char* completions_get_hint(completions_t* cms, ssize_t index, const char** help);
+ic_private void        completions_get_completer(completions_t* cms, ic_completer_fun_t** completer, void** arg);
+
+ic_private ssize_t     completions_apply(completions_t* cms, ssize_t index, stringbuf_t* sbuf, ssize_t pos);
+ic_private ssize_t     completions_apply_longest_prefix(completions_t* cms, stringbuf_t* sbuf, ssize_t pos);
+
+//-------------------------------------------------------------
+// Completion environment
+//-------------------------------------------------------------
+typedef bool (ic_completion_fun_t)( ic_env_t* env, void* funenv, const char* replacement, const char* display, const char* help, long delete_before, long delete_after );
+
+struct ic_completion_env_s {
+  ic_env_t*   env;       // the isocline environment
+  const char* input;     // current full input
+  long        cursor;    // current cursor position
+  void*       arg;       // argument given to `ic_set_completer`
+  void*       closure;   // free variables for function composition
+  ic_completion_fun_t* complete;  // function that adds a completion
+};
+
+#endif // IC_COMPLETIONS_H

extern/isocline/src/editline_completion.c

@@ -0,0 +1,277 @@
+/* ----------------------------------------------------------------------------
+  Copyright (c) 2021, Daan Leijen
+  This is free software; you can redistribute it and/or modify it
+  under the terms of the MIT License. A copy of the license can be
+  found in the "LICENSE" file at the root of this distribution.
+-----------------------------------------------------------------------------*/
+
+//-------------------------------------------------------------
+// Completion menu: this file is included in editline.c
+//-------------------------------------------------------------
+
+// return true if anything changed
+static bool edit_complete(ic_env_t* env, editor_t* eb, ssize_t idx) {
+  editor_start_modify(eb);
+  ssize_t newpos = completions_apply(env->completions, idx, eb->input, eb->pos);
+  if (newpos < 0) {
+    editor_undo_restore(eb,false);
+    return false;
+  }
+  eb->pos = newpos;
+  edit_refresh(env,eb);  
+  return true;
+}
+
+static bool edit_complete_longest_prefix(ic_env_t* env, editor_t* eb ) {
+  editor_start_modify(eb);
+  ssize_t newpos = completions_apply_longest_prefix( env->completions, eb->input, eb->pos );
+  if (newpos < 0) {
+    editor_undo_restore(eb,false);
+    return false;
+  }
+  eb->pos = newpos;
+  edit_refresh(env,eb);
+  return true;
+}
+
+ic_private void sbuf_append_tagged( stringbuf_t* sb, const char* tag, const char* content ) {
+  sbuf_appendf(sb, "[%s]", tag);  
+  sbuf_append(sb,content);
+  sbuf_append(sb,"[/]");
+}
+
+static void editor_append_completion(ic_env_t* env, editor_t* eb, ssize_t idx, ssize_t width, bool numbered, bool selected ) {
+  const char* help = NULL;
+  const char* display = completions_get_display(env->completions, idx, &help);
+  if (display == NULL) return;
+  if (numbered) {
+    sbuf_appendf(eb->extra, "[ic-info]%s%zd [/]", (selected ? (tty_is_utf8(env->tty) ? "\xE2\x86\x92" : "*") : " "), 1 + idx);
+    width -= 3;
+  }
+
+  if (width > 0) {
+    sbuf_appendf(eb->extra, "[width=\"%zd;left; ;on\"]", width );
+  }
+  if (selected) {
+    sbuf_append(eb->extra, "[ic-emphasis]");
+  }
+  sbuf_append(eb->extra, display);
+  if (selected) { sbuf_append(eb->extra,"[/ic-emphasis]"); }
+  if (help != NULL) {
+    sbuf_append(eb->extra, "  ");
+    sbuf_append_tagged(eb->extra, "ic-info", help );      
+  }
+  if (width > 0) { sbuf_append(eb->extra,"[/width]"); }  
+}
+
+// 2 and 3 column output up to 80 wide
+#define IC_DISPLAY2_MAX    34
+#define IC_DISPLAY2_COL    (3+IC_DISPLAY2_MAX)
+#define IC_DISPLAY2_WIDTH  (2*IC_DISPLAY2_COL + 2)    // 75
+
+#define IC_DISPLAY3_MAX    21
+#define IC_DISPLAY3_COL    (3+IC_DISPLAY3_MAX)
+#define IC_DISPLAY3_WIDTH  (3*IC_DISPLAY3_COL + 2*2)  // 76
+
+static void editor_append_completion2(ic_env_t* env, editor_t* eb, ssize_t col_width, ssize_t idx1, ssize_t idx2, ssize_t selected ) {  
+  editor_append_completion(env, eb, idx1, col_width, true, (idx1 == selected) );
+  sbuf_append( eb->extra, "  ");
+  editor_append_completion(env, eb, idx2, col_width, true, (idx2 == selected) );
+}
+
+static void editor_append_completion3(ic_env_t* env, editor_t* eb, ssize_t col_width, ssize_t idx1, ssize_t idx2, ssize_t idx3, ssize_t selected ) {  
+  editor_append_completion(env, eb, idx1, col_width, true, (idx1 == selected) );
+  sbuf_append( eb->extra, "  ");
+  editor_append_completion(env, eb, idx2, col_width, true, (idx2 == selected));
+  sbuf_append( eb->extra, "  ");
+  editor_append_completion(env, eb, idx3, col_width, true, (idx3 == selected) );
+}
+
+static ssize_t edit_completions_max_width( ic_env_t* env, ssize_t count ) {
+  ssize_t max_width = 0;
+  for( ssize_t i = 0; i < count; i++) {
+    const char* help = NULL;
+    ssize_t w = bbcode_column_width(env->bbcode, completions_get_display(env->completions, i, &help));
+    if (help != NULL) {
+      w += 2 + bbcode_column_width(env->bbcode, help);
+    }
+    if (w > max_width) {
+      max_width = w;
+    }
+  }
+  return max_width;
+}
+
+static void edit_completion_menu(ic_env_t* env, editor_t* eb, bool more_available) {
+  ssize_t count = completions_count(env->completions);
+  ssize_t count_displayed = count;
+  assert(count > 1);
+  ssize_t selected = (env->complete_nopreview ? 0 : -1); // select first or none
+  ssize_t percolumn = count;
+
+again:
+  // show first 9 (or 8) completions
+  sbuf_clear(eb->extra);
+  ssize_t twidth = term_get_width(env->term) - 1;
+  ssize_t colwidth;
+  if (count > 3 && ((colwidth = 3 + edit_completions_max_width(env, 9))*3 + 2*2) < twidth) {
+    // display as a 3 column block
+    count_displayed = (count > 9 ? 9 : count);
+    percolumn = 3;
+    for (ssize_t rw = 0; rw < percolumn; rw++) {
+      if (rw > 0) sbuf_append(eb->extra, "\n");
+      editor_append_completion3(env, eb, colwidth, rw, percolumn+rw, (2*percolumn)+rw, selected);
+    }
+  }
+  else if (count > 4 && ((colwidth = 3 + edit_completions_max_width(env, 8))*2 + 2) < twidth) {
+    // display as a 2 column block if some entries are too wide for three columns
+    count_displayed = (count > 8 ? 8 : count);
+    percolumn = (count_displayed <= 6 ? 3 : 4);
+    for (ssize_t rw = 0; rw < percolumn; rw++) {
+      if (rw > 0) sbuf_append(eb->extra, "\n");
+      editor_append_completion2(env, eb, colwidth, rw, percolumn+rw, selected);
+    }
+  }
+  else {
+    // display as a list
+    count_displayed = (count > 9 ? 9 : count);
+    percolumn = count_displayed;
+    for (ssize_t i = 0; i < count_displayed; i++) {
+      if (i > 0) sbuf_append(eb->extra, "\n");
+      editor_append_completion(env, eb, i, -1, true /* numbered */, selected == i);
+    }
+  }
+  if (count > count_displayed) {
+    if (more_available) {
+      sbuf_append(eb->extra, "\n[ic-info](press page-down (or ctrl-j) to see all further completions)[/]");
+    }
+    else {
+      sbuf_appendf(eb->extra, "\n[ic-info](press page-down (or ctrl-j) to see all %zd completions)[/]", count );
+    }
+  }
+  if (!env->complete_nopreview && selected >= 0 && selected <= count_displayed) {
+    edit_complete(env,eb,selected);
+    editor_undo_restore(eb,false);
+  }
+  else {
+    edit_refresh(env, eb);
+  }
+
+  // read here; if not a valid key, push it back and return to main event loop
+  code_t c = tty_read(env->tty);
+  if (tty_term_resize_event(env->tty)) {
+    edit_resize(env, eb);
+  }
+  sbuf_clear(eb->extra);
+  
+  // direct selection?
+  if (c >= '1' && c <= '9') {
+    ssize_t i = (c - '1');
+    if (i < count) {
+      selected = i;
+      c = KEY_ENTER;
+    }
+  }
+
+  // process commands
+  if (c == KEY_DOWN || c == KEY_TAB) {
+    selected++;
+    if (selected >= count_displayed) {
+      //term_beep(env->term);
+      selected = 0;
+    }
+    goto again;
+  }
+  else if (c == KEY_UP || c == KEY_SHIFT_TAB) {
+    selected--;
+    if (selected < 0) {
+      selected = count_displayed - 1;
+      //term_beep(env->term);
+    }
+    goto again;
+  }
+  else if (c == KEY_F1) {
+    edit_show_help(env, eb);
+    goto again;
+  }
+  else if (c == KEY_ESC) {
+    completions_clear(env->completions);
+    edit_refresh(env,eb);
+    c = 0; // ignore and return
+  }
+  else if (selected >= 0 && (c == KEY_ENTER || c == KEY_RIGHT || c == KEY_END)) /* || c == KEY_TAB*/ {  
+    // select the current entry
+    assert(selected < count);
+    c = 0;      
+    edit_complete(env, eb, selected);    
+    if (env->complete_autotab) {
+      tty_code_pushback(env->tty,KEY_EVENT_AUTOTAB); // immediately try to complete again        
+    }
+  }
+  else if (!env->complete_nopreview && !code_is_virt_key(c)) {
+    // if in preview mode, select the current entry and exit the menu
+    assert(selected < count);
+    edit_complete(env, eb, selected); 
+  }
+  else if ((c == KEY_PAGEDOWN || c == KEY_LINEFEED) && count > 9) {
+    // show all completions
+    c = 0;
+    if (more_available) {
+      // generate all entries (up to the max (= 1000))
+      count = completions_generate(env, env->completions, sbuf_string(eb->input), eb->pos, IC_MAX_COMPLETIONS_TO_SHOW);
+    }
+    rowcol_t rc;
+    edit_get_rowcol(env,eb,&rc);
+    edit_clear(env,eb);
+    edit_write_prompt(env,eb,0,false);
+    term_writeln(env->term, "");
+    for(ssize_t i = 0; i < count; i++) {
+      const char* display = completions_get_display(env->completions, i, NULL);
+      if (display != NULL) {
+        bbcode_println(env->bbcode, display);
+      }
+    }
+    if (count >= IC_MAX_COMPLETIONS_TO_SHOW) {
+      bbcode_println(env->bbcode, "[ic-info]... and more.[/]");
+    }
+    else {
+      bbcode_printf(env->bbcode, "[ic-info](%zd possible completions)[/]\n", count );
+    }
+    for(ssize_t i = 0; i < rc.row+1; i++) {
+      term_write(env->term, " \n");
+    }
+    eb->cur_rows = 0;
+    edit_refresh(env,eb);      
+  }
+  else {
+    edit_refresh(env,eb);
+  }
+  // done
+  completions_clear(env->completions);      
+  if (c != 0) tty_code_pushback(env->tty,c);
+}
+
+static void edit_generate_completions(ic_env_t* env, editor_t* eb, bool autotab) {
+  debug_msg( "edit: complete: %zd: %s\n", eb->pos, sbuf_string(eb->input) );
+  if (eb->pos < 0) return;
+  ssize_t count = completions_generate(env, env->completions, sbuf_string(eb->input), eb->pos, IC_MAX_COMPLETIONS_TO_TRY);
+  bool more_available = (count >= IC_MAX_COMPLETIONS_TO_TRY);
+  if (count <= 0) {
+    // no completions
+    if (!autotab) { term_beep(env->term); }
+  }
+  else if (count == 1) {
+    // complete if only one match    
+    if (edit_complete(env,eb,0 /*idx*/) && env->complete_autotab) {
+      tty_code_pushback(env->tty,KEY_EVENT_AUTOTAB);
+    }    
+  }
+  else {
+    //term_beep(env->term); 
+    if (!more_available) { 
+      edit_complete_longest_prefix(env,eb);
+    }    
+    completions_sort(env->completions);
+    edit_completion_menu( env, eb, more_available);    
+  }
+}

extern/isocline/src/editline_help.c

@@ -0,0 +1,140 @@
+/* ----------------------------------------------------------------------------
+  Copyright (c) 2021, Daan Leijen
+  This is free software; you can redistribute it and/or modify it
+  under the terms of the MIT License. A copy of the license can be
+  found in the "LICENSE" file at the root of this distribution.
+-----------------------------------------------------------------------------*/
+
+//-------------------------------------------------------------
+// Help: this is included into editline.c
+//-------------------------------------------------------------
+
+static const char* help[] = {
+  "","Navigation:",
+  "left,"
+  "^b",         "go one character to the left",
+  "right,"
+  "^f",         "go one character to the right",
+  "up",         "go one row up, or back in the history",
+  "down",       "go one row down, or forward in the history",
+  #ifdef __APPLE__
+  "shift-left",
+  #else
+  "^left",
+  #endif
+                "go to the start of the previous word",
+  #ifdef __APPLE__
+  "shift-right",
+  #else
+  "^right",
+  #endif
+                "go to the end the current word",
+  "home,"
+  "^a",         "go to the start of the current line",
+  "end,"
+  "^e",         "go to the end of the current line",
+  "pgup,"
+  "^home",       "go to the start of the current input",
+  "pgdn,"
+  "^end",       "go to the end of the current input",
+  "alt-m",      "jump to matching brace",
+  "^p",         "go back in the history",
+  "^n",         "go forward in the history",
+  "^r,^s",      "search the history starting with the current word",
+  "","",
+
+  "", "Deletion:",
+  "del,^d",     "delete the current character",
+  "backsp,^h",  "delete the previous character",
+  "^w",         "delete to preceding white space",
+  "alt-backsp", "delete to the start of the current word",
+  "alt-d",      "delete to the end of the current word",
+  "^u",         "delete to the start of the current line",
+  "^k",         "delete to the end of the current line",
+  "esc",        "delete the current input, or done with empty input",
+  "","",
+
+  "", "Editing:",
+  "enter",      "accept current input",
+  #ifndef __APPLE__
+  "^enter, ^j", "",
+  "shift-tab",
+  #else
+  "shift-tab,^j",
+  #endif
+                "create a new line for multi-line input",
+  //" ",          "(or type '\\' followed by enter)",
+  "^l",         "clear screen",
+  "^t",         "swap with previous character (move character backward)",
+  "^z,^_",      "undo",
+  "^y",         "redo",
+  //"^C",         "done with empty input",
+  //"F1",         "show this help",
+  "tab",        "try to complete the current input",
+  "","",
+  "","In the completion menu:",
+  "enter,left", "use the currently selected completion",
+  "1 - 9",      "use completion N from the menu",
+  "tab,down",   "select the next completion",
+  "shift-tab,up","select the previous completion",
+  "esc",        "exit menu without completing",
+  "pgdn,^j",    "show all further possible completions",
+  "","",
+  "","In incremental history search:",
+  "enter",      "use the currently found history entry",
+  "backsp,"
+  "^z",         "go back to the previous match (undo)",
+  "tab,"
+  "^r",         "find the next match",
+  "shift-tab,"
+  "^s",         "find an earlier match",
+  "esc",        "exit search",
+  " ","",
+  NULL, NULL
+};
+
+static const char* help_initial = 
+  "[ic-info]"
+  "Isocline v1.0, copyright (c) 2021 Daan Leijen.\n"
+  "This is free software; you can redistribute it and/or\n"
+  "modify it under the terms of the MIT License.\n"
+  "See <[url]https://github.com/daanx/isocline[/url]> for further information.\n"
+  "We use ^<key> as a shorthand for ctrl-<key>.\n"
+  "\n"
+  "Overview:\n"
+  "\n[ansi-lightgray]"
+  "       home,ctrl-a      cursor     end,ctrl-e\n"
+  "         ┌────────────────┼───────────────┐    (navigate)\n"
+  //"       │                │               │\n"
+  #ifndef __APPLE__
+  "         │    ctrl-left   │  ctrl-right   │\n"
+  #else
+  "         │     alt-left   │   alt-right   │\n"
+  #endif
+  "         │        ┌───────┼──────┐        │    ctrl-r   : search history\n"
+  "         ▼        ▼       ▼      ▼        ▼    tab      : complete word\n"
+  "  prompt> [ansi-darkgray]it's the quintessential language[/]     shift-tab: insert new line\n"
+  "         ▲        ▲              ▲        ▲    esc      : delete input, done\n"
+  "         │        └──────────────┘        │    ctrl-z   : undo\n"
+  "         │   alt-backsp        alt-d      │\n"
+  //"       │                │               │\n"
+  "         └────────────────────────────────┘    (delete)\n"
+  "       ctrl-u                          ctrl-k\n"
+  "[/ansi-lightgray][/ic-info]\n";
+
+static void edit_show_help(ic_env_t* env, editor_t* eb) {
+  edit_clear(env, eb);
+  bbcode_println(env->bbcode, help_initial);
+  for (ssize_t i = 0; help[i] != NULL && help[i+1] != NULL; i += 2) {
+    if (help[i][0] == 0) {  
+      bbcode_printf(env->bbcode, "[ic-info]%s[/]\n", help[i+1]);
+    }
+    else {
+      bbcode_printf(env->bbcode, "  [ic-emphasis]%-13s[/][ansi-lightgray]%s%s[/]\n", help[i], (help[i+1][0] == 0 ? "" : ": "), help[i+1]);
+    }
+  }
+
+  eb->cur_rows = 0;
+  eb->cur_row = 0;
+  edit_refresh(env, eb);
+}

extern/isocline/src/editline_history.c

@@ -0,0 +1,260 @@
+/* ----------------------------------------------------------------------------
+  Copyright (c) 2021, Daan Leijen
+  This is free software; you can redistribute it and/or modify it
+  under the terms of the MIT License. A copy of the license can be
+  found in the "LICENSE" file at the root of this distribution.
+-----------------------------------------------------------------------------*/
+
+//-------------------------------------------------------------
+// History search: this file is included in editline.c
+//-------------------------------------------------------------
+
+static void edit_history_at(ic_env_t* env, editor_t* eb, int ofs ) 
+{
+  if (eb->modified) { 
+    history_update(env->history, sbuf_string(eb->input)); // update first entry if modified
+    eb->history_idx = 0;          // and start again 
+    eb->modified = false;    
+  }
+  const char* entry = history_get(env->history,eb->history_idx + ofs);
+  // debug_msg( "edit: history: at: %d + %d, found: %s\n", eb->history_idx, ofs, entry);
+  if (entry == NULL) {
+    term_beep(env->term);
+  }
+  else {
+    eb->history_idx += ofs;
+    sbuf_replace(eb->input, entry);
+    if (ofs > 0) {
+      // at end of first line when scrolling up
+      ssize_t end = sbuf_find_line_end(eb->input,0);
+      eb->pos = (end < 0 ? 0 : end);
+    }
+    else {
+      eb->pos = sbuf_len(eb->input);    // at end of last line when scrolling down
+    }
+    edit_refresh(env, eb);
+  }
+}
+
+static void edit_history_prev(ic_env_t* env, editor_t* eb) {
+  edit_history_at(env,eb, 1 );
+}
+
+static void edit_history_next(ic_env_t* env, editor_t* eb) {
+  edit_history_at(env,eb, -1 );
+}
+
+typedef struct hsearch_s {
+  struct hsearch_s* next;
+  ssize_t hidx;
+  ssize_t match_pos;
+  ssize_t match_len;
+  bool cinsert;
+} hsearch_t;
+
+static void hsearch_push( alloc_t* mem, hsearch_t** hs, ssize_t hidx, ssize_t mpos, ssize_t mlen, bool cinsert ) {
+  hsearch_t* h = mem_zalloc_tp( mem, hsearch_t );
+  if (h == NULL) return;
+  h->hidx = hidx;
+  h->match_pos = mpos;
+  h->match_len = mlen;
+  h->cinsert = cinsert;
+  h->next = *hs;
+  *hs = h;
+}
+
+static bool hsearch_pop( alloc_t* mem, hsearch_t** hs, ssize_t* hidx, ssize_t* match_pos, ssize_t* match_len, bool* cinsert ) {
+  hsearch_t* h = *hs;
+  if (h == NULL) return false;
+  *hs = h->next;
+  if (hidx != NULL)      *hidx = h->hidx;
+  if (match_pos != NULL) *match_pos = h->match_pos;
+  if (match_len != NULL) *match_len = h->match_len;
+  if (cinsert != NULL)   *cinsert = h->cinsert;
+  mem_free(mem, h);
+  return true;
+}
+
+static void hsearch_done( alloc_t* mem, hsearch_t* hs ) {
+  while (hs != NULL) {
+    hsearch_t* next = hs->next;
+    mem_free(mem, hs);
+    hs = next;
+  }
+}
+
+static void edit_history_search(ic_env_t* env, editor_t* eb, char* initial ) {
+  if (history_count( env->history ) <= 0) {
+    term_beep(env->term);
+    return;
+  }
+
+  // update history
+  if (eb->modified) { 
+    history_update(env->history, sbuf_string(eb->input)); // update first entry if modified
+    eb->history_idx = 0;               // and start again 
+    eb->modified = false;
+  }
+
+  // set a search prompt and remember the previous state
+  editor_undo_capture(eb);
+  eb->disable_undo = true;
+  bool old_hint = ic_enable_hint(false);  
+  const char* prompt_text = eb->prompt_text;
+  eb->prompt_text = "history search";
+  
+  // search state
+  hsearch_t* hs = NULL;        // search undo 
+  ssize_t hidx = 1;            // current history entry
+  ssize_t match_pos = 0;       // current matched position
+  ssize_t match_len = 0;       // length of the match
+  const char* hentry = NULL;   // current history entry
+  
+  // Simulate per character searches for each letter in `initial` (so backspace works)
+  if (initial != NULL) {
+    const ssize_t initial_len = ic_strlen(initial);
+    ssize_t ipos = 0;
+    while( ipos < initial_len ) {
+      ssize_t next = str_next_ofs( initial, initial_len, ipos, NULL );
+      if (next < 0) break;
+      hsearch_push( eb->mem, &hs, hidx, match_pos, match_len, true);
+      char c = initial[ipos + next];  // terminate temporarily
+      initial[ipos + next] = 0;
+      if (history_search( env->history, hidx, initial, true, &hidx, &match_pos )) {
+        match_len = ipos + next;
+      }      
+      else if (ipos + next >= initial_len) {
+        term_beep(env->term);
+      }
+      initial[ipos + next] = c;       // restore
+      ipos += next;
+    }
+    sbuf_replace( eb->input, initial);
+    eb->pos = ipos;
+  }
+  else {
+    sbuf_clear( eb->input );
+    eb->pos = 0;
+  }
+
+  // Incremental search
+again:
+  hentry = history_get(env->history,hidx);
+  if (hentry != NULL) {
+    sbuf_appendf(eb->extra, "[ic-info]%zd. [/][ic-diminish][!pre]", hidx);
+    sbuf_append_n( eb->extra, hentry, match_pos );      
+    sbuf_append(eb->extra, "[/pre][u ic-emphasis][!pre]" ); 
+    sbuf_append_n( eb->extra, hentry + match_pos, match_len );
+    sbuf_append(eb->extra, "[/pre][/u][!pre]" ); 
+    sbuf_append(eb->extra, hentry + match_pos + match_len );
+    sbuf_append(eb->extra, "[/pre][/ic-diminish]");
+    if (!env->no_help) {
+      sbuf_append(eb->extra, "\n[ic-info](use tab for the next match)[/]");
+    }
+    sbuf_append(eb->extra, "\n" );
+  }
+  edit_refresh(env, eb);
+
+  // Wait for input
+  code_t c = (hentry == NULL ? KEY_ESC : tty_read(env->tty));
+  if (tty_term_resize_event(env->tty)) {
+    edit_resize(env, eb);
+  }
+  sbuf_clear(eb->extra);
+
+  // Process commands
+  if (c == KEY_ESC || c == KEY_BELL /* ^G */ || c == KEY_CTRL_C) {
+    c = 0;  
+    eb->disable_undo = false;
+    editor_undo_restore(eb, false);
+  } 
+  else if (c == KEY_ENTER) {
+    c = 0;
+    editor_undo_forget(eb);
+    sbuf_replace( eb->input, hentry );
+    eb->pos = sbuf_len(eb->input);
+    eb->modified = false;
+    eb->history_idx = hidx;
+  }  
+  else if (c == KEY_BACKSP || c == KEY_CTRL_Z) {
+    // undo last search action
+    bool cinsert;
+    if (hsearch_pop(env->mem,&hs, &hidx, &match_pos, &match_len, &cinsert)) {
+      if (cinsert) edit_backspace(env,eb);
+    }
+    goto again;
+  }
+  else if (c == KEY_CTRL_R || c == KEY_TAB || c == KEY_UP) {    
+    // search backward
+    hsearch_push(env->mem, &hs, hidx, match_pos, match_len, false);
+    if (!history_search( env->history, hidx+1, sbuf_string(eb->input), true, &hidx, &match_pos )) {
+      hsearch_pop(env->mem,&hs,NULL,NULL,NULL,NULL);
+      term_beep(env->term);
+    };
+    goto again;
+  }  
+  else if (c == KEY_CTRL_S || c == KEY_SHIFT_TAB || c == KEY_DOWN) {    
+    // search forward
+    hsearch_push(env->mem, &hs, hidx, match_pos, match_len, false);
+    if (!history_search( env->history, hidx-1, sbuf_string(eb->input), false, &hidx, &match_pos )) {
+      hsearch_pop(env->mem, &hs,NULL,NULL,NULL,NULL);
+      term_beep(env->term);
+    };
+    goto again;
+  }
+  else if (c == KEY_F1) {
+    edit_show_help(env, eb);
+    goto again;
+  }
+  else {
+    // insert character and search further backward
+    char chr;
+    unicode_t uchr;
+    if (code_is_ascii_char(c,&chr)) {
+      hsearch_push(env->mem, &hs, hidx, match_pos, match_len, true);
+      edit_insert_char(env,eb,chr);      
+    }
+    else if (code_is_unicode(c,&uchr)) {
+      hsearch_push(env->mem, &hs, hidx, match_pos, match_len, true);
+      edit_insert_unicode(env,eb,uchr);
+    }
+    else {
+      // ignore command
+      term_beep(env->term);
+      goto again;
+    }
+    // search for the new input
+    if (history_search( env->history, hidx, sbuf_string(eb->input), true, &hidx, &match_pos )) {
+      match_len = sbuf_len(eb->input);
+    }
+    else {
+      term_beep(env->term);
+    };
+    goto again;
+  }
+
+  // done
+  eb->disable_undo = false;
+  hsearch_done(env->mem,hs);
+  eb->prompt_text = prompt_text;
+  ic_enable_hint(old_hint);
+  edit_refresh(env,eb);
+  if (c != 0) tty_code_pushback(env->tty, c);
+}
+
+// Start an incremental search with the current word 
+static void edit_history_search_with_current_word(ic_env_t* env, editor_t* eb) {
+  char* initial = NULL;
+  ssize_t start = sbuf_find_word_start( eb->input, eb->pos );
+  if (start >= 0) {
+    const ssize_t next = sbuf_next(eb->input, start, NULL);
+    if (!ic_char_is_idletter(sbuf_string(eb->input) + start, (long)(next - start))) { 
+      start = next; 
+    }
+    if (start >= 0 && start < eb->pos) {
+      initial = mem_strndup(eb->mem, sbuf_string(eb->input) + start, eb->pos - start);
+    }
+  }
+  edit_history_search( env, eb, initial);
+  mem_free(env->mem, initial);
+}

extern/isocline/src/env.h

@@ -0,0 +1,60 @@
+/* ----------------------------------------------------------------------------
+  Copyright (c) 2021, Daan Leijen
+  This is free software; you can redistribute it and/or modify it
+  under the terms of the MIT License. A copy of the license can be
+  found in the "LICENSE" file at the root of this distribution.
+-----------------------------------------------------------------------------*/
+#pragma once
+#ifndef IC_ENV_H
+#define IC_ENV_H
+
+#include "../include/isocline.h"
+#include "common.h"
+#include "term.h"
+#include "tty.h"
+#include "stringbuf.h"
+#include "history.h"
+#include "completions.h"
+#include "bbcode.h"
+
+//-------------------------------------------------------------
+// Environment
+//-------------------------------------------------------------
+
+struct ic_env_s {
+  alloc_t*        mem;              // potential custom allocator
+  ic_env_t*       next;             // next environment (used for proper deallocation)
+  term_t*         term;             // terminal
+  tty_t*          tty;              // keyboard (NULL if stdin is a pipe, file, etc)
+  completions_t*  completions;      // current completions
+  history_t*      history;          // edit history
+  bbcode_t*       bbcode;           // print with bbcodes
+  const char*     prompt_marker;    // the prompt marker (defaults to "> ")
+  const char*     cprompt_marker;   // prompt marker for continuation lines (defaults to `prompt_marker`)
+  ic_highlight_fun_t* highlighter;  // highlight callback
+  void*           highlighter_arg;  // user state for the highlighter.
+  const char*     match_braces;     // matching braces, e.g "()[]{}"
+  const char*     auto_braces;      // auto insertion braces, e.g "()[]{}\"\"''"
+  char            multiline_eol;    // character used for multiline input ("\") (set to 0 to disable)
+  bool            initialized;      // are we initialized?
+  bool            noedit;           // is rich editing possible (tty != NULL)
+  bool            singleline_only;  // allow only single line editing?
+  bool            complete_nopreview; // do not show completion preview for each selection in the completion menu?
+  bool            complete_autotab; // try to keep completing after a completion?
+  bool            no_multiline_indent; // indent continuation lines to line up under the initial prompt 
+  bool            no_help;          // show short help line for history search etc.
+  bool            no_hint;          // allow hinting?
+  bool            no_highlight;     // enable highlighting?
+  bool            no_bracematch;    // enable brace matching?
+  bool            no_autobrace;     // enable automatic brace insertion?
+  bool            no_lscolors;      // use LSCOLORS/LS_COLORS to colorize file name completions?
+  long            hint_delay;       // delay before displaying a hint in milliseconds
+};
+
+ic_private char*        ic_editline(ic_env_t* env, const char* prompt_text);
+
+ic_private ic_env_t*    ic_get_env(void);
+ic_private const char*  ic_env_get_auto_braces(ic_env_t* env);
+ic_private const char*  ic_env_get_match_braces(ic_env_t* env);
+
+#endif // IC_ENV_H

extern/isocline/src/highlight.c

@@ -0,0 +1,259 @@
+/* ----------------------------------------------------------------------------
+  Copyright (c) 2021, Daan Leijen
+  This is free software; you can redistribute it and/or modify it
+  under the terms of the MIT License. A copy of the license can be
+  found in the "LICENSE" file at the root of this distribution.
+-----------------------------------------------------------------------------*/
+
+#include <string.h>
+#include "common.h"
+#include "term.h"
+#include "stringbuf.h"
+#include "attr.h"
+#include "bbcode.h"
+
+//-------------------------------------------------------------
+// Syntax highlighting
+//-------------------------------------------------------------
+
+struct ic_highlight_env_s {
+  attrbuf_t*    attrs;
+  const char*   input;   
+  ssize_t       input_len;     
+  bbcode_t*     bbcode;
+  alloc_t*      mem;
+  ssize_t       cached_upos;  // cached unicode position
+  ssize_t       cached_cpos;  // corresponding utf-8 byte position
+};
+
+
+ic_private void highlight( alloc_t* mem, bbcode_t* bb, const char* s, attrbuf_t* attrs, ic_highlight_fun_t* highlighter, void* arg ) {
+  const ssize_t len = ic_strlen(s);
+  if (len <= 0) return;
+  attrbuf_set_at(attrs,0,len,attr_none()); // fill to length of s
+  if (highlighter != NULL) {
+    ic_highlight_env_t henv;
+    henv.attrs = attrs;
+    henv.input = s;     
+    henv.input_len = len;
+    henv.bbcode = bb;
+    henv.mem = mem;
+    henv.cached_cpos = 0;
+    henv.cached_upos = 0;
+    (*highlighter)( &henv, s, arg );    
+  }
+}
+
+
+//-------------------------------------------------------------
+// Client interface
+//-------------------------------------------------------------
+
+static void pos_adjust( ic_highlight_env_t* henv, ssize_t* ppos, ssize_t* plen ) {
+  ssize_t pos = *ppos;
+  ssize_t len = *plen;
+  if (pos >= henv->input_len) return;
+  if (pos >= 0 && len >= 0) return;   // already character positions
+  if (henv->input == NULL) return;
+
+  if (pos < 0) {
+    // negative `pos` is used as the unicode character position (for easy interfacing with Haskell)
+    ssize_t upos = -pos;
+    ssize_t cpos = 0;
+    ssize_t ucount = 0;
+    if (henv->cached_upos <= upos) {  // if we have a cached position, start from there
+      ucount = henv->cached_upos;
+      cpos = henv->cached_cpos;
+    }
+    while ( ucount < upos ) {
+      ssize_t next = str_next_ofs(henv->input, henv->input_len, cpos, NULL);
+      if (next <= 0) return;
+      ucount++;
+      cpos += next;
+    }
+    *ppos = pos = cpos;
+    // and cache it to avoid quadratic behavior
+    henv->cached_upos = upos;
+    henv->cached_cpos = cpos;
+  }
+  if (len < 0) {
+    // negative `len` is used as a unicode character length
+    len = -len;
+    ssize_t ucount = 0;
+    ssize_t clen   = 0;    
+    while (ucount < len) {
+      ssize_t next = str_next_ofs(henv->input, henv->input_len, pos + clen, NULL);
+      if (next <= 0) return;
+      ucount++;
+      clen += next;
+    }
+    *plen = len = clen;
+    // and update cache if possible
+    if (henv->cached_cpos == pos) {
+      henv->cached_upos += ucount;
+      henv->cached_cpos += clen;
+    }
+  } 
+}
+
+static void highlight_attr(ic_highlight_env_t* henv, ssize_t pos, ssize_t count, attr_t attr ) {
+  if (henv==NULL) return;
+  pos_adjust(henv,&pos,&count);
+  if (pos < 0 || count <= 0) return;
+  attrbuf_update_at(henv->attrs, pos, count, attr);
+}
+
+ic_public void ic_highlight(ic_highlight_env_t* henv, long pos, long count, const char* style ) {
+  if (henv == NULL || style==NULL || style[0]==0 || pos < 0) return;  
+  highlight_attr(henv,pos,count,bbcode_style( henv->bbcode, style ));
+}
+
+ic_public void ic_highlight_formatted(ic_highlight_env_t* henv, const char* s, const char* fmt) {
+  if (s==NULL || s[0] == 0 || fmt==NULL) return;
+  attrbuf_t* attrs = attrbuf_new(henv->mem);
+  stringbuf_t* out = sbuf_new(henv->mem);  // todo: avoid allocating out?
+  if (attrs!=NULL && out != NULL) {
+    bbcode_append( henv->bbcode, fmt, out, attrs);
+    const ssize_t len = ic_strlen(s);
+    if (sbuf_len(out) != len) {
+      debug_msg("highlight: formatted string content differs from the original input:\n  original: %s\n  formatted: %s\n", s, fmt);
+    }
+    for( ssize_t i = 0; i < len; i++) {
+      attrbuf_update_at(henv->attrs, i, 1, attrbuf_attr_at(attrs,i));
+    }
+  }
+  sbuf_free(out);
+  attrbuf_free(attrs);
+}
+
+//-------------------------------------------------------------
+// Brace matching
+//-------------------------------------------------------------
+#define MAX_NESTING (64)
+
+typedef struct brace_s {
+  char    close;
+  bool    at_cursor;
+  ssize_t pos;
+} brace_t;
+
+ic_private void highlight_match_braces(const char* s, attrbuf_t* attrs, ssize_t cursor_pos, const char* braces, attr_t match_attr, attr_t error_attr) 
+{
+  brace_t open[MAX_NESTING+1];
+  ssize_t nesting = 0;
+  const ssize_t brace_len = ic_strlen(braces);
+  for (long i = 0; i < ic_strlen(s); i++) {
+    const char c = s[i];
+    // push open brace
+    bool found_open = false;
+    for (ssize_t b = 0; b < brace_len; b += 2) {
+      if (c == braces[b]) {
+        // open brace
+        if (nesting >= MAX_NESTING) return; // give up
+        open[nesting].close = braces[b+1];
+        open[nesting].pos = i;
+        open[nesting].at_cursor = (i == cursor_pos - 1);
+        nesting++;
+        found_open = true;
+        break;
+      }
+    }
+    if (found_open) continue;
+
+    // pop to closing brace and potentially highlight
+    for (ssize_t b = 1; b < brace_len; b += 2) {
+      if (c == braces[b]) {
+        // close brace
+        if (nesting <= 0) {
+          // unmatched close brace
+          attrbuf_update_at( attrs, i, 1, error_attr);
+        }
+        else {
+          // can we fix an unmatched brace where we can match by popping just one?
+          if (open[nesting-1].close != c && nesting > 1 && open[nesting-2].close == c) {
+            // assume previous open brace was wrong
+            attrbuf_update_at(attrs, open[nesting-1].pos, 1, error_attr);
+            nesting--;
+          }
+          if (open[nesting-1].close != c) {
+            // unmatched open brace
+            attrbuf_update_at( attrs, i, 1, error_attr);
+          }
+          else {
+            // matching brace
+            nesting--;
+            if (i == cursor_pos - 1 || (open[nesting].at_cursor && open[nesting].pos != i - 1)) {
+              // highlight matching brace
+              attrbuf_update_at(attrs, open[nesting].pos, 1, match_attr);
+              attrbuf_update_at(attrs, i, 1, match_attr);              
+            }
+          }
+        }
+        break;
+      }
+    }
+  }
+  // note: don't mark further unmatched open braces as in error
+}
+
+
+ic_private ssize_t find_matching_brace(const char* s, ssize_t cursor_pos, const char* braces, bool* is_balanced) 
+{
+  if (is_balanced != NULL) { *is_balanced = false; }
+  bool balanced = true;
+  ssize_t match = -1;
+  brace_t open[MAX_NESTING+1];
+  ssize_t nesting = 0;
+  const ssize_t brace_len = ic_strlen(braces);
+  for (long i = 0; i < ic_strlen(s); i++) {
+    const char c = s[i];
+    // push open brace
+    bool found_open = false;
+    for (ssize_t b = 0; b < brace_len; b += 2) {
+      if (c == braces[b]) {
+        // open brace
+        if (nesting >= MAX_NESTING) return -1; // give up
+        open[nesting].close = braces[b+1];
+        open[nesting].pos = i;
+        open[nesting].at_cursor = (i == cursor_pos - 1);
+        nesting++;
+        found_open = true;
+        break;
+      }
+    }
+    if (found_open) continue;
+
+    // pop to closing brace 
+    for (ssize_t b = 1; b < brace_len; b += 2) {
+      if (c == braces[b]) {
+        // close brace
+        if (nesting <= 0) {
+          // unmatched close brace
+          balanced = false;          
+        }
+        else {
+          if (open[nesting-1].close != c) {
+            // unmatched open brace
+            balanced = false;
+          }
+          else {
+            // matching brace
+            nesting--;
+            if (i == cursor_pos - 1) {
+              // found matching open brace
+              match = open[nesting].pos + 1;
+            }
+            else if (open[nesting].at_cursor) {
+              // found matching close brace
+              match = i + 1;
+            }
+          }
+        }
+        break; 
+      }
+    }
+  }
+  if (nesting != 0) { balanced = false; }
+  if (is_balanced != NULL) { *is_balanced = balanced; }
+  return match;
+}

extern/isocline/src/highlight.h

@@ -0,0 +1,24 @@
+/* ----------------------------------------------------------------------------
+  Copyright (c) 2021, Daan Leijen
+  This is free software; you can redistribute it and/or modify it
+  under the terms of the MIT License. A copy of the license can be
+  found in the "LICENSE" file at the root of this distribution.
+-----------------------------------------------------------------------------*/
+#pragma once
+#ifndef IC_HIGHLIGHT_H
+#define IC_HIGHLIGHT_H
+
+#include "common.h"
+#include "attr.h"
+#include "term.h"
+#include "bbcode.h"
+
+//-------------------------------------------------------------
+// Syntax highlighting
+//-------------------------------------------------------------
+
+ic_private void highlight( alloc_t* mem, bbcode_t* bb, const char* s, attrbuf_t* attrs, ic_highlight_fun_t* highlighter, void* arg );
+ic_private void highlight_match_braces(const char* s, attrbuf_t* attrs, ssize_t cursor_pos, const char* braces, attr_t match_attr, attr_t error_attr);
+ic_private ssize_t find_matching_brace(const char* s, ssize_t cursor_pos, const char* braces, bool* is_balanced);
+
+#endif // IC_HIGHLIGHT_H

extern/isocline/src/history.c

@@ -0,0 +1,269 @@
+/* ----------------------------------------------------------------------------
+  Copyright (c) 2021, Daan Leijen
+  This is free software; you can redistribute it and/or modify it
+  under the terms of the MIT License. A copy of the license can be
+  found in the "LICENSE" file at the root of this distribution.
+-----------------------------------------------------------------------------*/
+#include <stdio.h>
+#include <string.h>  
+#include <sys/stat.h>
+
+#include "../include/isocline.h"
+#include "common.h"
+#include "history.h"
+#include "stringbuf.h"
+
+#define IC_MAX_HISTORY (200)
+
+struct history_s {
+  ssize_t  count;              // current number of entries in use
+  ssize_t  len;                // size of elems 
+  const char** elems;         // history items (up to count)
+  const char*  fname;         // history file
+  alloc_t* mem;
+  bool     allow_duplicates;   // allow duplicate entries?
+};
+
+ic_private history_t* history_new(alloc_t* mem) {
+  history_t* h = mem_zalloc_tp(mem,history_t);
+  h->mem = mem;
+  return h;
+}
+
+ic_private void history_free(history_t* h) {
+  if (h == NULL) return;
+  history_clear(h);
+  if (h->len > 0) {
+    mem_free( h->mem, h->elems );
+    h->elems = NULL;
+    h->len = 0;
+  }
+  mem_free(h->mem, h->fname);
+  h->fname = NULL;
+  mem_free(h->mem, h); // free ourselves
+}
+
+ic_private bool history_enable_duplicates( history_t* h, bool enable ) {
+  bool prev = h->allow_duplicates;
+  h->allow_duplicates = enable;
+  return prev;
+}
+
+ic_private ssize_t  history_count(const history_t* h) {
+  return h->count;
+}
+
+//-------------------------------------------------------------
+// push/clear
+//-------------------------------------------------------------
+
+ic_private bool history_update( history_t* h, const char* entry ) {
+  if (entry==NULL) return false;
+  history_remove_last(h);
+  history_push(h,entry);
+  //debug_msg("history: update: with %s; now at %s\n", entry, history_get(h,0));
+  return true;
+}
+
+static void history_delete_at( history_t* h, ssize_t idx ) {
+  if (idx < 0 || idx >= h->count) return;
+  mem_free(h->mem, h->elems[idx]);
+  for(ssize_t i = idx+1; i < h->count; i++) {
+    h->elems[i-1] = h->elems[i];
+  }
+  h->count--;
+}
+
+ic_private bool history_push( history_t* h, const char* entry ) {
+  if (h->len <= 0 || entry==NULL)  return false;
+  // remove any older duplicate
+  if (!h->allow_duplicates) {
+    for( int i = 0; i < h->count; i++) {
+      if (strcmp(h->elems[i],entry) == 0) {
+        history_delete_at(h,i);
+      }
+    }
+  }
+  // insert at front
+  if (h->count == h->len) {
+    // delete oldest entry
+    history_delete_at(h,0);    
+  }
+  assert(h->count < h->len);
+  h->elems[h->count] = mem_strdup(h->mem,entry);
+  h->count++;
+  return true;
+}
+
+
+static void history_remove_last_n( history_t* h, ssize_t n ) {
+  if (n <= 0) return;
+  if (n > h->count) n = h->count;
+  for( ssize_t i = h->count - n; i < h->count; i++) {
+    mem_free( h->mem, h->elems[i] );
+  }
+  h->count -= n;
+  assert(h->count >= 0);    
+}
+
+ic_private void history_remove_last(history_t* h) {
+  history_remove_last_n(h,1);
+}
+
+ic_private void history_clear(history_t* h) {
+  history_remove_last_n( h, h->count );
+}
+
+ic_private const char* history_get( const history_t* h, ssize_t n ) {
+  if (n < 0 || n >= h->count) return NULL;
+  return h->elems[h->count - n - 1];
+}
+
+ic_private bool history_search( const history_t* h, ssize_t from /*including*/, const char* search, bool backward, ssize_t* hidx, ssize_t* hpos ) {
+  const char* p = NULL;
+  ssize_t i;
+  if (backward) {
+    for( i = from; i < h->count; i++ ) {
+      p = strstr( history_get(h,i), search);
+      if (p != NULL) break;
+    }
+  }
+  else {
+    for( i = from; i >= 0; i-- ) {
+      p = strstr( history_get(h,i), search);
+      if (p != NULL) break;
+    }
+  }
+  if (p == NULL) return false;
+  if (hidx != NULL) *hidx = i;
+  if (hpos != NULL) *hpos = (p - history_get(h,i));
+  return true;
+}
+
+//-------------------------------------------------------------
+// 
+//-------------------------------------------------------------
+
+ic_private void history_load_from(history_t* h, const char* fname, long max_entries ) {
+  history_clear(h);
+  h->fname = mem_strdup(h->mem,fname);
+  if (max_entries == 0) {
+    assert(h->elems == NULL);
+    return;
+  }
+  if (max_entries < 0 || max_entries > IC_MAX_HISTORY) max_entries = IC_MAX_HISTORY;
+  h->elems = (const char**)mem_zalloc_tp_n(h->mem, char*, max_entries );
+  if (h->elems == NULL) return;
+  h->len = max_entries;
+  history_load(h);
+}
+
+
+
+
+//-------------------------------------------------------------
+// save/load history to file
+//-------------------------------------------------------------
+
+static char from_xdigit( int c ) {
+  if (c >= '0' && c <= '9') return (char)(c - '0');
+  if (c >= 'A' && c <= 'F') return (char)(10 + (c - 'A'));
+  if (c >= 'a' && c <= 'f') return (char)(10 + (c - 'a'));
+  return 0;
+}
+
+static char to_xdigit( uint8_t c ) {
+  if (c <= 9) return ((char)c + '0');
+  if (c >= 10 && c <= 15) return ((char)c - 10 + 'A');
+  return '0';
+}
+
+static bool ic_isxdigit( int c ) {
+  return ((c >= 'a' && c <= 'f') || (c >= 'A' && c <= 'F') || (c >= '0' && c <= '9'));
+}
+
+static bool history_read_entry( history_t* h, FILE* f, stringbuf_t* sbuf ) {
+  sbuf_clear(sbuf);
+  while( !feof(f)) {
+    int c = fgetc(f);
+    if (c == EOF || c == '\n') break;
+    if (c == '\\') {
+      c = fgetc(f);
+      if (c == 'n')       { sbuf_append(sbuf,"\n"); }
+      else if (c == 'r')  { /* ignore */ }  // sbuf_append(sbuf,"\r");
+      else if (c == 't')  { sbuf_append(sbuf,"\t"); }
+      else if (c == '\\') { sbuf_append(sbuf,"\\"); }
+      else if (c == 'x') {
+        int c1 = fgetc(f);         
+        int c2 = fgetc(f);
+        if (ic_isxdigit(c1) && ic_isxdigit(c2)) {
+          char chr = from_xdigit(c1)*16 + from_xdigit(c2);
+          sbuf_append_char(sbuf,chr);
+        }
+        else return false;
+      }
+      else return false;
+    }
+    else sbuf_append_char(sbuf,(char)c);
+  }
+  if (sbuf_len(sbuf)==0 || sbuf_string(sbuf)[0] == '#') return true;
+  return history_push(h, sbuf_string(sbuf));
+}
+
+static bool history_write_entry( const char* entry, FILE* f, stringbuf_t* sbuf ) {
+  sbuf_clear(sbuf);
+  //debug_msg("history: write: %s\n", entry);
+  while( entry != NULL && *entry != 0 ) {
+    char c = *entry++;
+    if (c == '\\')      { sbuf_append(sbuf,"\\\\"); }
+    else if (c == '\n') { sbuf_append(sbuf,"\\n"); }
+    else if (c == '\r') { /* ignore */ } // sbuf_append(sbuf,"\\r"); }
+    else if (c == '\t') { sbuf_append(sbuf,"\\t"); }
+    else if (c < ' ' || c > '~' || c == '#') {
+      char c1 = to_xdigit( (uint8_t)c / 16 );
+      char c2 = to_xdigit( (uint8_t)c % 16 );
+      sbuf_append(sbuf,"\\x"); 
+      sbuf_append_char(sbuf,c1); 
+      sbuf_append_char(sbuf,c2);            
+    }
+    else sbuf_append_char(sbuf,c);
+  }
+  //debug_msg("history: write buf: %s\n", sbuf_string(sbuf));
+  
+  if (sbuf_len(sbuf) > 0) {
+    sbuf_append(sbuf,"\n");
+    fputs(sbuf_string(sbuf),f);
+  }
+  return true;
+}
+
+ic_private void history_load( history_t* h ) {
+  if (h->fname == NULL) return;
+  FILE* f = fopen(h->fname, "r");
+  if (f == NULL) return;
+  stringbuf_t* sbuf = sbuf_new(h->mem);
+  if (sbuf != NULL) {
+    while (!feof(f)) {
+      if (!history_read_entry(h,f,sbuf)) break; // error
+    }
+    sbuf_free(sbuf);
+  }
+  fclose(f);
+}
+
+ic_private void history_save( const history_t* h ) {
+  if (h->fname == NULL) return;
+  FILE* f = fopen(h->fname, "w");
+  if (f == NULL) return;
+  #ifndef _WIN32
+  chmod(h->fname,S_IRUSR|S_IWUSR);
+  #endif
+  stringbuf_t* sbuf = sbuf_new(h->mem);
+  if (sbuf != NULL) {
+    for( int i = 0; i < h->count; i++ )  {
+      if (!history_write_entry(h->elems[i],f,sbuf)) break;  // error
+    }
+    sbuf_free(sbuf);
+  }
+  fclose(f);  
+}

extern/isocline/src/history.h

@@ -0,0 +1,38 @@
+/* ----------------------------------------------------------------------------
+  Copyright (c) 2021, Daan Leijen
+  This is free software; you can redistribute it and/or modify it
+  under the terms of the MIT License. A copy of the license can be
+  found in the "LICENSE" file at the root of this distribution.
+-----------------------------------------------------------------------------*/
+#pragma once
+#ifndef IC_HISTORY_H
+#define IC_HISTORY_H
+
+#include "common.h"
+
+//-------------------------------------------------------------
+// History
+//-------------------------------------------------------------
+
+struct history_s;
+typedef struct history_s history_t;
+
+ic_private history_t* history_new(alloc_t* mem);
+ic_private void     history_free(history_t* h);
+ic_private void     history_clear(history_t* h);
+ic_private bool     history_enable_duplicates( history_t* h, bool enable );
+ic_private ssize_t  history_count(const history_t* h);
+
+ic_private void     history_load_from(history_t* h, const char* fname, long max_entries);
+ic_private void     history_load( history_t* h );
+ic_private void     history_save( const history_t* h );
+
+ic_private bool     history_push( history_t* h, const char* entry );
+ic_private bool     history_update( history_t* h, const char* entry );
+ic_private const char* history_get( const history_t* h, ssize_t n );
+ic_private void     history_remove_last(history_t* h);
+
+ic_private bool     history_search( const history_t* h, ssize_t from, const char* search, bool backward, ssize_t* hidx, ssize_t* hpos);
+
+
+#endif // IC_HISTORY_H

extern/isocline/src/isocline.c

@@ -0,0 +1,594 @@
+/* ----------------------------------------------------------------------------
+  Copyright (c) 2021, Daan Leijen
+  This is free software; you can redistribute it and/or modify it
+  under the terms of the MIT License. A copy of the license can be
+  found in the "LICENSE" file at the root of this distribution.
+-----------------------------------------------------------------------------*/
+
+//-------------------------------------------------------------
+// Usually we include all sources one file so no internal 
+// symbols are public in the libray.
+// 
+// You can compile the entire library just as: 
+// $ gcc -c src/isocline.c 
+//-------------------------------------------------------------
+#if !defined(IC_SEPARATE_OBJS)
+# ifndef _CRT_NONSTDC_NO_WARNINGS
+#  define _CRT_NONSTDC_NO_WARNINGS // for msvc
+# endif
+# ifndef _CRT_SECURE_NO_WARNINGS
+#  define _CRT_SECURE_NO_WARNINGS  // for msvc
+# endif
+# define _XOPEN_SOURCE   700      // for wcwidth
+# define _DEFAULT_SOURCE          // ensure usleep stays visible with _XOPEN_SOURCE >= 700
+# include "attr.c"
+# include "bbcode.c"
+# include "editline.c"
+# include "highlight.c"
+# include "undo.c"
+# include "history.c"
+# include "completers.c"
+# include "completions.c"
+# include "term.c"
+# include "tty_esc.c"
+# include "tty.c"
+# include "stringbuf.c"
+# include "common.c"
+#endif
+
+//-------------------------------------------------------------
+// includes
+//-------------------------------------------------------------
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdarg.h>
+
+#include "../include/isocline.h"
+#include "common.h"
+#include "env.h"
+
+
+//-------------------------------------------------------------
+// Readline
+//-------------------------------------------------------------
+
+static char*  ic_getline( alloc_t* mem );
+
+ic_public char* ic_readline(const char* prompt_text) 
+{
+  ic_env_t* env = ic_get_env();
+  if (env == NULL) return NULL;
+  if (!env->noedit) {
+    // terminal editing enabled
+    return ic_editline(env, prompt_text);   // in editline.c
+  } 
+  else {
+    // no editing capability (pipe, dumb terminal, etc)
+    if (env->tty != NULL && env->term != NULL) {
+      // if the terminal is not interactive, but we are reading from the tty (keyboard), we display a prompt
+      term_start_raw(env->term);  // set utf8 mode on windows
+      if (prompt_text != NULL) {
+        term_write(env->term, prompt_text);
+      }
+      term_write(env->term, env->prompt_marker);    
+      term_end_raw(env->term, false);
+    }
+    // read directly from stdin
+    return ic_getline(env->mem);
+  }
+}
+
+
+//-------------------------------------------------------------
+// Read a line from the stdin stream if there is no editing 
+// support (like from a pipe, file, or dumb terminal).
+//-------------------------------------------------------------
+
+static char* ic_getline(alloc_t* mem)
+{  
+  // read until eof or newline
+  stringbuf_t* sb = sbuf_new(mem);
+  int c;
+  while (true) {
+    c = fgetc(stdin);
+    if (c==EOF || c=='\n') {
+      break;
+    }
+    else {
+      sbuf_append_char(sb, (char)c);
+    }
+  }
+  return sbuf_free_dup(sb);
+}
+
+
+//-------------------------------------------------------------
+// Formatted output
+//-------------------------------------------------------------
+
+
+ic_public void ic_printf(const char* fmt, ...) {
+  va_list ap;
+  va_start(ap, fmt);
+  ic_vprintf(fmt, ap);
+  va_end(ap);
+}
+
+ic_public void ic_vprintf(const char* fmt, va_list args) {
+  ic_env_t* env = ic_get_env(); if (env==NULL || env->bbcode == NULL) return;
+  bbcode_vprintf(env->bbcode, fmt, args);
+}
+
+ic_public void ic_print(const char* s) {
+  ic_env_t* env = ic_get_env(); if (env==NULL || env->bbcode==NULL) return;
+  bbcode_print(env->bbcode, s);
+}
+
+ic_public void ic_println(const char* s) {
+  ic_env_t* env = ic_get_env(); if (env==NULL || env->bbcode==NULL) return;
+  bbcode_println(env->bbcode, s);
+}
+
+void ic_style_def(const char* name, const char* fmt) {
+  ic_env_t* env = ic_get_env(); if (env==NULL || env->bbcode==NULL) return;
+  bbcode_style_def(env->bbcode, name, fmt);
+}
+
+void ic_style_open(const char* fmt) {
+  ic_env_t* env = ic_get_env(); if (env==NULL || env->bbcode==NULL) return;
+  bbcode_style_open(env->bbcode, fmt);
+}
+
+void ic_style_close(void) {
+  ic_env_t* env = ic_get_env(); if (env==NULL || env->bbcode==NULL) return;
+  bbcode_style_close(env->bbcode, NULL);
+}
+
+
+//-------------------------------------------------------------
+// Interface
+//-------------------------------------------------------------
+
+ic_public bool ic_async_stop(void) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return false;
+  if (env->tty==NULL) return false;
+  return tty_async_stop(env->tty);
+}
+
+static void set_prompt_marker(ic_env_t* env, const char* prompt_marker, const char* cprompt_marker) {
+  if (prompt_marker == NULL) prompt_marker = "> ";
+  if (cprompt_marker == NULL) cprompt_marker = prompt_marker;
+  mem_free(env->mem, env->prompt_marker);
+  mem_free(env->mem, env->cprompt_marker);
+  env->prompt_marker = mem_strdup(env->mem, prompt_marker);
+  env->cprompt_marker = mem_strdup(env->mem, cprompt_marker);
+}
+
+ic_public const char* ic_get_prompt_marker(void) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return NULL;
+  return env->prompt_marker;
+}
+
+ic_public const char* ic_get_continuation_prompt_marker(void) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return NULL;
+  return env->cprompt_marker;
+}
+
+ic_public void ic_set_prompt_marker( const char* prompt_marker, const char* cprompt_marker ) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return;
+  set_prompt_marker(env, prompt_marker, cprompt_marker);
+}
+
+ic_public bool ic_enable_multiline( bool enable ) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return false;
+  bool prev = env->singleline_only;
+  env->singleline_only = !enable;
+  return !prev;
+}
+
+ic_public bool ic_enable_beep( bool enable ) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return false;
+  return term_enable_beep(env->term, enable);
+}
+
+ic_public bool ic_enable_color( bool enable ) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return false;
+  return term_enable_color( env->term, enable );
+}
+
+ic_public bool ic_enable_history_duplicates( bool enable ) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return false;
+  return history_enable_duplicates(env->history, enable);
+}
+
+ic_public void ic_set_history(const char* fname, long max_entries ) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return;
+  history_load_from(env->history, fname, max_entries );
+}
+
+ic_public void ic_history_remove_last(void) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return;
+  history_remove_last(env->history);
+}
+
+ic_public void ic_history_add( const char* entry ) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return;
+  history_push( env->history, entry );
+}
+
+ic_public void ic_history_clear(void) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return;
+  history_clear(env->history);
+}
+
+ic_public bool ic_enable_auto_tab( bool enable ) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return false;
+  bool prev = env->complete_autotab;
+  env->complete_autotab = enable;
+  return prev;
+}
+
+ic_public bool ic_enable_completion_preview( bool enable ) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return false;
+  bool prev = env->complete_nopreview;
+  env->complete_nopreview = !enable;
+  return !prev;
+}
+
+ic_public bool ic_enable_multiline_indent(bool enable) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return false;
+  bool prev = env->no_multiline_indent;
+  env->no_multiline_indent = !enable;
+  return !prev;
+}
+
+ic_public bool ic_enable_hint(bool enable) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return false;
+  bool prev = env->no_hint;
+  env->no_hint = !enable;
+  return !prev;
+}
+
+ic_public long ic_set_hint_delay(long delay_ms) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return false;
+  long prev = env->hint_delay;
+  env->hint_delay = (delay_ms < 0 ? 0 : (delay_ms > 5000 ? 5000 : delay_ms));
+  return prev;
+}
+
+ic_public void ic_set_tty_esc_delay(long initial_delay_ms, long followup_delay_ms ) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return;
+  if (env->tty == NULL) return;
+  tty_set_esc_delay(env->tty, initial_delay_ms, followup_delay_ms);
+}
+
+
+ic_public bool ic_enable_highlight(bool enable) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return false;
+  bool prev = env->no_highlight;
+  env->no_highlight = !enable;
+  return !prev;
+}
+
+ic_public bool ic_enable_inline_help(bool enable) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return false;
+  bool prev = env->no_help;
+  env->no_help = !enable;
+  return !prev;
+}
+
+ic_public bool ic_enable_brace_matching(bool enable) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return false;
+  bool prev = env->no_bracematch;
+  env->no_bracematch = !enable;
+  return !prev;
+}
+
+ic_public void ic_set_matching_braces(const char* brace_pairs) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return;
+  mem_free(env->mem, env->match_braces);
+  env->match_braces = NULL;
+  if (brace_pairs != NULL) {
+    ssize_t len = ic_strlen(brace_pairs);
+    if (len > 0 && (len % 2) == 0) {
+      env->match_braces = mem_strdup(env->mem, brace_pairs);
+    }
+  }
+}
+
+ic_public bool ic_enable_brace_insertion(bool enable) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return false;
+  bool prev = env->no_autobrace;
+  env->no_autobrace = !enable;
+  return !prev;
+}
+
+ic_public void ic_set_insertion_braces(const char* brace_pairs) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return;
+  mem_free(env->mem, env->auto_braces);
+  env->auto_braces = NULL;
+  if (brace_pairs != NULL) {
+    ssize_t len = ic_strlen(brace_pairs);
+    if (len > 0 && (len % 2) == 0) { 
+      env->auto_braces = mem_strdup(env->mem, brace_pairs);
+    }
+  }
+}
+
+ic_private const char* ic_env_get_match_braces(ic_env_t* env) {
+  return (env->match_braces == NULL ? "()[]{}" : env->match_braces);
+}
+
+ic_private const char* ic_env_get_auto_braces(ic_env_t* env) {
+  return (env->auto_braces == NULL ? "()[]{}\"\"''" : env->auto_braces);
+}
+
+ic_public void ic_set_default_highlighter(ic_highlight_fun_t* highlighter, void* arg) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return;
+  env->highlighter = highlighter;
+  env->highlighter_arg = arg;
+}
+
+
+ic_public void ic_free( void* p ) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return;
+  mem_free(env->mem, p);
+}
+
+ic_public void* ic_malloc(size_t sz) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return NULL;
+  return mem_malloc(env->mem, to_ssize_t(sz));
+}
+
+ic_public const char* ic_strdup( const char* s ) {
+  if (s==NULL) return NULL;
+  ic_env_t* env = ic_get_env(); if (env==NULL) return NULL;
+  ssize_t len = ic_strlen(s);
+  char* p = mem_malloc_tp_n( env->mem, char, len + 1 );
+  if (p == NULL) return NULL;
+  ic_memcpy( p, s, len );
+  p[len] = 0;
+  return p;
+}
+
+//-------------------------------------------------------------
+// Terminal
+//-------------------------------------------------------------
+
+ic_public void ic_term_init(void) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return;
+  if (env->term==NULL) return;
+  term_start_raw(env->term);
+}
+
+ic_public void ic_term_done(void) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return;
+  if (env->term==NULL) return;
+  term_end_raw(env->term,false);
+}
+
+ic_public void ic_term_flush(void) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return;
+  if (env->term==NULL) return;
+  term_flush(env->term);
+}
+
+ic_public void ic_term_write(const char* s) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return;
+  if (env->term == NULL) return;
+  term_write(env->term, s);
+}
+
+ic_public void ic_term_writeln(const char* s) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return;
+  if (env->term == NULL) return;
+  term_writeln(env->term, s);
+}
+
+ic_public void ic_term_writef(const char* fmt, ...) {
+  va_list ap;
+  va_start(ap, fmt);
+  ic_term_vwritef(fmt, ap);
+  va_end(ap);
+}
+
+ic_public void ic_term_vwritef(const char* fmt, va_list args) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return;
+  if (env->term == NULL) return;
+  term_vwritef(env->term, fmt, args);
+}
+
+ic_public void ic_term_reset( void )  {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return;
+  if (env->term == NULL) return;
+  term_attr_reset(env->term);
+}
+
+ic_public void ic_term_style( const char* style ) {
+  ic_env_t* env = ic_get_env(); if (env==NULL) return;
+  if (env->term == NULL || env->bbcode == NULL) return;
+  term_set_attr( env->term, bbcode_style(env->bbcode, style));
+}
+
+ic_public int ic_term_get_color_bits(void) {
+  ic_env_t* env = ic_get_env(); 
+  if (env==NULL || env->term==NULL) return 4;  
+  return term_get_color_bits(env->term);
+}
+
+ic_public void ic_term_bold(bool enable) {
+  ic_env_t* env = ic_get_env(); if (env==NULL || env->term==NULL) return;
+  term_bold(env->term, enable);
+}
+
+ic_public void ic_term_underline(bool enable) {
+  ic_env_t* env = ic_get_env(); if (env==NULL || env->term==NULL) return;
+  term_underline(env->term, enable);
+}
+
+ic_public void ic_term_italic(bool enable) {
+  ic_env_t* env = ic_get_env(); if (env==NULL || env->term==NULL) return;
+  term_italic(env->term, enable);
+}
+
+ic_public void ic_term_reverse(bool enable) {
+  ic_env_t* env = ic_get_env(); if (env==NULL || env->term==NULL) return;
+  term_reverse(env->term, enable);
+}
+
+ic_public void ic_term_color_ansi(bool foreground, int ansi_color) {
+  ic_env_t* env = ic_get_env(); if (env==NULL || env->term==NULL) return;
+  ic_color_t color = color_from_ansi256(ansi_color);
+  if (foreground) { term_color(env->term, color); }
+             else { term_bgcolor(env->term, color); }
+}
+
+ic_public void ic_term_color_rgb(bool foreground, uint32_t hcolor) {
+  ic_env_t* env = ic_get_env(); if (env==NULL || env->term==NULL) return;
+  ic_color_t color = ic_rgb(hcolor);
+  if (foreground) { term_color(env->term, color); }
+             else { term_bgcolor(env->term, color); }
+}
+
+
+//-------------------------------------------------------------
+// Readline with temporary completer and highlighter
+//-------------------------------------------------------------
+
+ic_public char* ic_readline_ex(const char* prompt_text,
+                                ic_completer_fun_t* completer, void* completer_arg,
+                                 ic_highlight_fun_t* highlighter, void* highlighter_arg )
+{
+  ic_env_t* env = ic_get_env(); if (env == NULL) return NULL;
+  // save previous
+  ic_completer_fun_t* prev_completer;
+  void* prev_completer_arg;
+  completions_get_completer(env->completions, &prev_completer, &prev_completer_arg);
+  ic_highlight_fun_t* prev_highlighter = env->highlighter;
+  void* prev_highlighter_arg = env->highlighter_arg;
+  // call with current
+  if (completer != NULL)   { ic_set_default_completer(completer, completer_arg); }
+  if (highlighter != NULL) { ic_set_default_highlighter(highlighter, highlighter_arg); }
+  char* res = ic_readline(prompt_text);
+  // restore previous
+  ic_set_default_completer(prev_completer, prev_completer_arg);
+  ic_set_default_highlighter(prev_highlighter, prev_highlighter_arg);
+  return res;
+}
+
+
+//-------------------------------------------------------------
+// Initialize
+//-------------------------------------------------------------
+
+static void ic_atexit(void);
+
+static void ic_env_free(ic_env_t* env) {
+  if (env == NULL) return;
+  history_save(env->history);
+  history_free(env->history);
+  completions_free(env->completions);
+  bbcode_free(env->bbcode);
+  term_free(env->term);
+  tty_free(env->tty);
+  mem_free(env->mem, env->cprompt_marker);
+  mem_free(env->mem,env->prompt_marker);
+  mem_free(env->mem, env->match_braces);
+  mem_free(env->mem, env->auto_braces);
+  env->prompt_marker = NULL;
+  
+  // and deallocate ourselves
+  alloc_t* mem = env->mem;  
+  mem_free(mem, env);
+
+  // and finally the custom memory allocation structure
+  mem_free(mem, mem);
+}
+
+
+static ic_env_t* ic_env_create( ic_malloc_fun_t* _malloc, ic_realloc_fun_t* _realloc, ic_free_fun_t* _free )  
+{
+  if (_malloc == NULL)  _malloc = &malloc;
+  if (_realloc == NULL) _realloc = &realloc;
+  if (_free == NULL)    _free = &free;
+  // allocate
+  alloc_t* mem = (alloc_t*)_malloc(sizeof(alloc_t));
+  if (mem == NULL) return NULL;
+  mem->malloc = _malloc;
+  mem->realloc = _realloc;
+  mem->free = _free;
+  ic_env_t* env = mem_zalloc_tp(mem, ic_env_t);
+  if (env==NULL) {
+    mem->free(mem);
+    return NULL;
+  }
+  env->mem = mem;
+
+  // Initialize
+  env->tty         = tty_new(env->mem, -1);  // can return NULL
+  env->term        = term_new(env->mem, env->tty, false, false, -1 );  
+  env->history     = history_new(env->mem);
+  env->completions = completions_new(env->mem);
+  env->bbcode      = bbcode_new(env->mem, env->term);
+  env->hint_delay  = 400;   
+  
+  if (env->tty == NULL || env->term==NULL ||
+      env->completions == NULL || env->history == NULL || env->bbcode == NULL ||
+      !term_is_interactive(env->term)) 
+  {
+    env->noedit = true;
+  }
+  env->multiline_eol = '\\';
+  
+  bbcode_style_def(env->bbcode, "ic-prompt",    "ansi-green" );
+  bbcode_style_def(env->bbcode, "ic-info",      "ansi-darkgray" );
+  bbcode_style_def(env->bbcode, "ic-diminish",  "ansi-lightgray" );
+  bbcode_style_def(env->bbcode, "ic-emphasis",  "#ffffd7" );
+  bbcode_style_def(env->bbcode, "ic-hint",      "ansi-darkgray" );
+  bbcode_style_def(env->bbcode, "ic-error",     "#d70000" );
+  bbcode_style_def(env->bbcode, "ic-bracematch","ansi-white"); //  color = #F7DC6F" );
+
+  bbcode_style_def(env->bbcode, "keyword",  "#569cd6" );
+  bbcode_style_def(env->bbcode, "control",  "#c586c0" );
+  bbcode_style_def(env->bbcode, "number",   "#b5cea8" );
+  bbcode_style_def(env->bbcode, "string",   "#ce9178" );
+  bbcode_style_def(env->bbcode, "comment",  "#6A9955" );
+  bbcode_style_def(env->bbcode, "type",     "darkcyan" );
+  bbcode_style_def(env->bbcode, "constant", "#569cd6" );
+
+  set_prompt_marker(env, NULL, NULL);
+  return env;
+}
+
+static ic_env_t* rpenv;
+
+static void ic_atexit(void) {
+  if (rpenv != NULL) {
+    ic_env_free(rpenv);
+    rpenv = NULL;
+  }
+}
+
+ic_private ic_env_t* ic_get_env(void) {  
+  if (rpenv==NULL) {
+    rpenv = ic_env_create( NULL, NULL, NULL );
+    if (rpenv != NULL) { atexit( &ic_atexit ); }
+  }
+  return rpenv;
+}
+
+ic_public void ic_init_custom_malloc( ic_malloc_fun_t* _malloc, ic_realloc_fun_t* _realloc, ic_free_fun_t* _free ) {
+  assert(rpenv == NULL);
+  if (rpenv != NULL) {
+    ic_env_free(rpenv);    
+    rpenv = ic_env_create( _malloc, _realloc, _free ); 
+  }
+  else {
+    rpenv = ic_env_create( _malloc, _realloc, _free ); 
+    if (rpenv != NULL) {
+      atexit( &ic_atexit );
+    }
+  }
+}
+

extern/isocline/src/stringbuf.h

@@ -0,0 +1,121 @@
+/* ----------------------------------------------------------------------------
+  Copyright (c) 2021, Daan Leijen
+  This is free software; you can redistribute it and/or modify it
+  under the terms of the MIT License. A copy of the license can be
+  found in the "LICENSE" file at the root of this distribution.
+-----------------------------------------------------------------------------*/
+#pragma once
+#ifndef IC_STRINGBUF_H
+#define IC_STRINGBUF_H
+
+#include <stdarg.h>
+#include "common.h"
+
+//-------------------------------------------------------------
+// string buffer
+// in-place modified buffer with edit operations 
+// that grows on demand.
+//-------------------------------------------------------------
+
+// abstract string buffer
+struct stringbuf_s;
+typedef struct stringbuf_s stringbuf_t;
+
+ic_private stringbuf_t*  sbuf_new( alloc_t* mem );
+ic_private void    sbuf_free( stringbuf_t* sbuf );
+ic_private char*   sbuf_free_dup(stringbuf_t* sbuf);
+ic_private ssize_t sbuf_len(const stringbuf_t* s);
+
+ic_private const char* sbuf_string_at( stringbuf_t* sbuf, ssize_t pos );
+ic_private const char* sbuf_string( stringbuf_t* sbuf );
+ic_private char    sbuf_char_at(stringbuf_t* sbuf, ssize_t pos);
+ic_private char*   sbuf_strdup_at( stringbuf_t* sbuf, ssize_t pos );
+ic_private char*   sbuf_strdup( stringbuf_t* sbuf );
+ic_private char*   sbuf_strdup_from_utf8(stringbuf_t* sbuf);  // decode to locale
+
+
+ic_private ssize_t sbuf_appendf(stringbuf_t* sb, const char* fmt, ...);
+ic_private ssize_t sbuf_append_vprintf(stringbuf_t* sb, const char* fmt, va_list args);
+
+ic_private stringbuf_t* sbuf_split_at( stringbuf_t* sb, ssize_t pos );
+
+// primitive edit operations (inserts return the new position)
+ic_private void    sbuf_clear(stringbuf_t* sbuf);
+ic_private void    sbuf_replace(stringbuf_t* sbuf, const char* s);
+ic_private void    sbuf_delete_at(stringbuf_t* sbuf, ssize_t pos, ssize_t count);
+ic_private void    sbuf_delete_from_to(stringbuf_t* sbuf, ssize_t pos, ssize_t end);
+ic_private void    sbuf_delete_from(stringbuf_t* sbuf, ssize_t pos );
+ic_private ssize_t sbuf_insert_at_n(stringbuf_t* sbuf, const char* s, ssize_t n, ssize_t pos );
+ic_private ssize_t sbuf_insert_at(stringbuf_t* sbuf, const char* s, ssize_t pos );
+ic_private ssize_t sbuf_insert_char_at(stringbuf_t* sbuf, char c, ssize_t pos );
+ic_private ssize_t sbuf_insert_unicode_at(stringbuf_t* sbuf, unicode_t u, ssize_t pos);
+ic_private ssize_t sbuf_append_n(stringbuf_t* sbuf, const char* s, ssize_t n);
+ic_private ssize_t sbuf_append(stringbuf_t* sbuf, const char* s);
+ic_private ssize_t sbuf_append_char(stringbuf_t* sbuf, char c);
+
+// high level edit operations (return the new position)
+ic_private ssize_t sbuf_next( stringbuf_t* sbuf, ssize_t pos, ssize_t* cwidth );
+ic_private ssize_t sbuf_prev( stringbuf_t* sbuf, ssize_t pos, ssize_t* cwidth );
+ic_private ssize_t sbuf_next_ofs(stringbuf_t* sbuf, ssize_t pos, ssize_t* cwidth);
+
+ic_private ssize_t sbuf_delete_char_before( stringbuf_t* sbuf, ssize_t pos );
+ic_private void    sbuf_delete_char_at( stringbuf_t* sbuf, ssize_t pos );
+ic_private ssize_t sbuf_swap_char( stringbuf_t* sbuf, ssize_t pos );
+
+ic_private ssize_t sbuf_find_line_start( stringbuf_t* sbuf, ssize_t pos );
+ic_private ssize_t sbuf_find_line_end( stringbuf_t* sbuf, ssize_t pos );
+ic_private ssize_t sbuf_find_word_start( stringbuf_t* sbuf, ssize_t pos );
+ic_private ssize_t sbuf_find_word_end( stringbuf_t* sbuf, ssize_t pos );
+ic_private ssize_t sbuf_find_ws_word_start( stringbuf_t* sbuf, ssize_t pos );
+ic_private ssize_t sbuf_find_ws_word_end( stringbuf_t* sbuf, ssize_t pos );
+
+// parse a decimal 
+ic_private bool ic_atoz(const char* s, ssize_t* i);
+// parse two decimals separated by a semicolon
+ic_private bool ic_atoz2(const char* s, ssize_t* i, ssize_t* j);
+ic_private bool ic_atou32(const char* s, uint32_t* pu);
+
+// row/column info
+typedef struct rowcol_s {
+  ssize_t row;
+  ssize_t col;
+  ssize_t row_start;
+  ssize_t row_len;
+  bool    first_on_row;
+  bool    last_on_row;
+} rowcol_t;
+
+// find row/col position
+ic_private ssize_t sbuf_get_pos_at_rc( stringbuf_t* sbuf, ssize_t termw, ssize_t promptw, ssize_t cpromptw, 
+                                       ssize_t row, ssize_t col );
+// get row/col for a given position
+ic_private ssize_t sbuf_get_rc_at_pos( stringbuf_t* sbuf, ssize_t termw, ssize_t promptw, ssize_t cpromptw, 
+                                       ssize_t pos, rowcol_t* rc );
+
+ic_private ssize_t sbuf_get_wrapped_rc_at_pos( stringbuf_t* sbuf, ssize_t termw, ssize_t newtermw, ssize_t promptw, ssize_t cpromptw, 
+                                       ssize_t pos, rowcol_t* rc );
+                                       
+// row iteration
+typedef bool (row_fun_t)(const char* s,
+                          ssize_t row, ssize_t row_start, ssize_t row_len, 
+                          ssize_t startw, // prompt width
+                          bool is_wrap, const void* arg, void* res);
+
+ic_private ssize_t sbuf_for_each_row( stringbuf_t* sbuf, ssize_t termw, ssize_t promptw, ssize_t cpromptw, 
+                                      row_fun_t* fun, void* arg, void* res );
+
+
+//-------------------------------------------------------------
+// Strings
+//-------------------------------------------------------------
+
+// skip a single CSI sequence (ESC [ ...)
+ic_private bool    skip_csi_esc( const char* s, ssize_t len, ssize_t* esclen ); // used in term.c
+
+ic_private ssize_t str_column_width( const char* s );
+ic_private ssize_t str_prev_ofs( const char* s, ssize_t pos, ssize_t* cwidth );
+ic_private ssize_t str_next_ofs( const char* s, ssize_t len, ssize_t pos, ssize_t* cwidth );
+ic_private ssize_t str_skip_until_fit( const char* s, ssize_t max_width);  // tail that fits
+ic_private ssize_t str_take_while_fit( const char* s, ssize_t max_width);  // prefix that fits
+
+#endif // IC_STRINGBUF_H

extern/isocline/src/term.h

@@ -0,0 +1,85 @@
+/* ----------------------------------------------------------------------------
+  Copyright (c) 2021, Daan Leijen
+  This is free software; you can redistribute it and/or modify it
+  under the terms of the MIT License. A copy of the license can be
+  found in the "LICENSE" file at the root of this distribution.
+-----------------------------------------------------------------------------*/
+#pragma once
+#ifndef IC_TERM_H
+#define IC_TERM_H
+
+#include "common.h"
+#include "tty.h"
+#include "stringbuf.h"
+#include "attr.h"
+
+struct term_s;
+typedef struct term_s term_t;
+
+typedef enum buffer_mode_e {
+  UNBUFFERED,
+  LINEBUFFERED,
+  BUFFERED,
+} buffer_mode_t;
+
+// Primitives
+ic_private term_t* term_new(alloc_t* mem, tty_t* tty, bool nocolor, bool silent, int fd_out);
+ic_private void term_free(term_t* term);
+
+ic_private bool term_is_interactive(const term_t* term);
+ic_private void term_start_raw(term_t* term);
+ic_private void term_end_raw(term_t* term, bool force);
+
+ic_private bool term_enable_beep(term_t* term, bool enable);
+ic_private bool term_enable_color(term_t* term, bool enable);
+
+ic_private void term_flush(term_t* term);
+ic_private buffer_mode_t term_set_buffer_mode(term_t* term, buffer_mode_t mode);
+
+ic_private void term_write_n(term_t* term, const char* s, ssize_t n);
+ic_private void term_write(term_t* term, const char* s);
+ic_private void term_writeln(term_t* term, const char* s);
+ic_private void term_write_char(term_t* term, char c);
+
+ic_private void term_write_repeat(term_t* term, const char* s, ssize_t count );
+ic_private void term_beep(term_t* term);
+
+ic_private bool term_update_dim(term_t* term);
+
+ic_private ssize_t term_get_width(term_t* term);
+ic_private ssize_t term_get_height(term_t* term);
+ic_private int  term_get_color_bits(term_t* term);
+
+// Helpers
+ic_private void term_writef(term_t* term, const char* fmt, ...);
+ic_private void term_vwritef(term_t* term, const char* fmt, va_list args);
+
+ic_private void term_left(term_t* term, ssize_t n);
+ic_private void term_right(term_t* term, ssize_t n);
+ic_private void term_up(term_t* term, ssize_t n);
+ic_private void term_down(term_t* term, ssize_t n);
+ic_private void term_start_of_line(term_t* term );
+ic_private void term_clear_line(term_t* term);
+ic_private void term_clear_to_end_of_line(term_t* term);
+// ic_private void term_clear_lines_to_end(term_t* term);
+
+
+ic_private void term_attr_reset(term_t* term);
+ic_private void term_underline(term_t* term, bool on);
+ic_private void term_reverse(term_t* term, bool on);
+ic_private void term_bold(term_t* term, bool on);
+ic_private void term_italic(term_t* term, bool on);
+
+ic_private void term_color(term_t* term, ic_color_t color);
+ic_private void term_bgcolor(term_t* term, ic_color_t color);
+
+// Formatted output
+
+ic_private attr_t term_get_attr( const term_t* term );
+ic_private void   term_set_attr( term_t* term, attr_t attr );
+ic_private void   term_write_formatted( term_t* term, const char* s, const attr_t* attrs );
+ic_private void   term_write_formatted_n( term_t* term, const char* s, const attr_t* attrs, ssize_t n );
+
+ic_private ic_color_t color_from_ansi256(ssize_t i);
+
+#endif // IC_TERM_H

extern/isocline/src/term_color.c

@@ -0,0 +1,371 @@
+/* ----------------------------------------------------------------------------
+  Copyright (c) 2021, Daan Leijen
+  This is free software; you can redistribute it and/or modify it
+  under the terms of the MIT License. A copy of the license can be
+  found in the "LICENSE" file at the root of this distribution.
+-----------------------------------------------------------------------------*/
+
+// This file is included in "term.c"
+
+//-------------------------------------------------------------
+// Standard ANSI palette for 256 colors
+//-------------------------------------------------------------
+
+static uint32_t ansi256[256] = {   
+  // not const as on some platforms (e.g. Windows, xterm) we update the first 16 entries with the actual used colors.
+  // 0, standard ANSI
+  0x000000, 0x800000, 0x008000, 0x808000, 0x000080, 0x800080, 
+  0x008080, 0xc0c0c0,
+  // 8, bright ANSI
+  0x808080, 0xff0000, 0x00ff00, 0xffff00, 0x0000ff, 0xff00ff, 
+  0x00ffff, 0xffffff,
+  // 6x6x6 RGB colors
+  // 16
+  0x000000, 0x00005f, 0x000087, 0x0000af, 0x0000d7, 0x0000ff,
+  0x005f00, 0x005f5f, 0x005f87, 0x005faf, 0x005fd7, 0x005fff,
+  0x008700, 0x00875f, 0x008787, 0x0087af, 0x0087d7, 0x0087ff,
+  0x00af00, 0x00af5f, 0x00af87, 0x00afaf, 0x00afd7, 0x00afff,
+  0x00d700, 0x00d75f, 0x00d787, 0x00d7af, 0x00d7d7, 0x00d7ff,
+  0x00ff00, 0x00ff5f, 0x00ff87, 0x00ffaf, 0x00ffd7, 0x00ffff,
+  // 52
+  0x5f0000, 0x5f005f, 0x5f0087, 0x5f00af, 0x5f00d7, 0x5f00ff,
+  0x5f5f00, 0x5f5f5f, 0x5f5f87, 0x5f5faf, 0x5f5fd7, 0x5f5fff,
+  0x5f8700, 0x5f875f, 0x5f8787, 0x5f87af, 0x5f87d7, 0x5f87ff,
+  0x5faf00, 0x5faf5f, 0x5faf87, 0x5fafaf, 0x5fafd7, 0x5fafff,
+  0x5fd700, 0x5fd75f, 0x5fd787, 0x5fd7af, 0x5fd7d7, 0x5fd7ff,
+  0x5fff00, 0x5fff5f, 0x5fff87, 0x5fffaf, 0x5fffd7, 0x5fffff,
+  // 88
+  0x870000, 0x87005f, 0x870087, 0x8700af, 0x8700d7, 0x8700ff,
+  0x875f00, 0x875f5f, 0x875f87, 0x875faf, 0x875fd7, 0x875fff,
+  0x878700, 0x87875f, 0x878787, 0x8787af, 0x8787d7, 0x8787ff,
+  0x87af00, 0x87af5f, 0x87af87, 0x87afaf, 0x87afd7, 0x87afff,
+  0x87d700, 0x87d75f, 0x87d787, 0x87d7af, 0x87d7d7, 0x87d7ff,
+  0x87ff00, 0x87ff5f, 0x87ff87, 0x87ffaf, 0x87ffd7, 0x87ffff,
+  // 124
+  0xaf0000, 0xaf005f, 0xaf0087, 0xaf00af, 0xaf00d7, 0xaf00ff,
+  0xaf5f00, 0xaf5f5f, 0xaf5f87, 0xaf5faf, 0xaf5fd7, 0xaf5fff,
+  0xaf8700, 0xaf875f, 0xaf8787, 0xaf87af, 0xaf87d7, 0xaf87ff,
+  0xafaf00, 0xafaf5f, 0xafaf87, 0xafafaf, 0xafafd7, 0xafafff,
+  0xafd700, 0xafd75f, 0xafd787, 0xafd7af, 0xafd7d7, 0xafd7ff,
+  0xafff00, 0xafff5f, 0xafff87, 0xafffaf, 0xafffd7, 0xafffff,
+  // 160
+  0xd70000, 0xd7005f, 0xd70087, 0xd700af, 0xd700d7, 0xd700ff,
+  0xd75f00, 0xd75f5f, 0xd75f87, 0xd75faf, 0xd75fd7, 0xd75fff,
+  0xd78700, 0xd7875f, 0xd78787, 0xd787af, 0xd787d7, 0xd787ff,
+  0xd7af00, 0xd7af5f, 0xd7af87, 0xd7afaf, 0xd7afd7, 0xd7afff,
+  0xd7d700, 0xd7d75f, 0xd7d787, 0xd7d7af, 0xd7d7d7, 0xd7d7ff,
+  0xd7ff00, 0xd7ff5f, 0xd7ff87, 0xd7ffaf, 0xd7ffd7, 0xd7ffff,
+  // 196
+  0xff0000, 0xff005f, 0xff0087, 0xff00af, 0xff00d7, 0xff00ff,
+  0xff5f00, 0xff5f5f, 0xff5f87, 0xff5faf, 0xff5fd7, 0xff5fff,
+  0xff8700, 0xff875f, 0xff8787, 0xff87af, 0xff87d7, 0xff87ff,
+  0xffaf00, 0xffaf5f, 0xffaf87, 0xffafaf, 0xffafd7, 0xffafff,
+  0xffd700, 0xffd75f, 0xffd787, 0xffd7af, 0xffd7d7, 0xffd7ff,
+  0xffff00, 0xffff5f, 0xffff87, 0xffffaf, 0xffffd7, 0xffffff,
+  // 232, gray scale
+  0x080808, 0x121212, 0x1c1c1c, 0x262626, 0x303030, 0x3a3a3a, 
+  0x444444, 0x4e4e4e, 0x585858, 0x626262, 0x6c6c6c, 0x767676, 
+  0x808080, 0x8a8a8a, 0x949494, 0x9e9e9e, 0xa8a8a8, 0xb2b2b2, 
+  0xbcbcbc, 0xc6c6c6, 0xd0d0d0, 0xdadada, 0xe4e4e4, 0xeeeeee   
+};
+
+
+//-------------------------------------------------------------
+// Create colors
+//-------------------------------------------------------------
+
+// Create a color from a 24-bit color value.
+ic_private ic_color_t ic_rgb(uint32_t hex) {
+  return (ic_color_t)(0x1000000 | (hex & 0xFFFFFF));
+}
+
+// Limit an int to values between 0 and 255.
+static uint32_t ic_cap8(ssize_t i) {
+  return (i < 0 ? 0 : (i > 255 ? 255 : (uint32_t)i));
+}
+
+// Create a color from a 24-bit color value.
+ic_private ic_color_t ic_rgbx(ssize_t r, ssize_t g, ssize_t b) {
+  return ic_rgb( (ic_cap8(r)<<16) | (ic_cap8(g)<<8) | ic_cap8(b) );
+}
+
+
+//-------------------------------------------------------------
+// Match an rgb color to a ansi8, ansi16, or ansi256
+//-------------------------------------------------------------
+
+static bool color_is_rgb( ic_color_t color ) {
+  return (color >= IC_RGB(0));  // bit 24 is set for rgb colors
+}
+
+static void color_to_rgb(ic_color_t color, int* r, int* g, int* b) {
+  assert(color_is_rgb(color));
+  *r = ((color >> 16) & 0xFF);
+  *g = ((color >> 8) & 0xFF);
+  *b = (color & 0xFF);
+}
+
+ic_private ic_color_t color_from_ansi256(ssize_t i) {
+  if (i >= 0 && i < 8) {
+    return (IC_ANSI_BLACK + (uint32_t)i);
+  }
+  else if (i >= 8 && i < 16) {
+    return (IC_ANSI_DARKGRAY + (uint32_t)(i - 8));
+  }
+  else if (i >= 16 && i <= 255) {
+    return ic_rgb( ansi256[i] );
+  }
+  else if (i == 256) {
+    return IC_ANSI_DEFAULT;
+  }
+  else {
+    return IC_ANSI_DEFAULT;
+  }
+}
+
+static bool is_grayish(int r, int g, int b) {
+  return (abs(r-g) <= 4) && (abs((r+g)/2 - b) <= 4);
+}
+
+static bool is_grayish_color( uint32_t rgb ) {
+  int r, g, b;
+  color_to_rgb(IC_RGB(rgb),&r,&g,&b);
+  return is_grayish(r,g,b);
+}
+
+static int_least32_t sqr(int_least32_t x) {
+  return x*x;
+}
+
+// Approximation to delta-E CIE color distance using much 
+// simpler calculations. See <https://www.compuphase.com/cmetric.htm>.
+// This is essentialy weighted euclidean distance but the weight distribution
+// depends on how big the "red" component of the color is.
+// We do not take the square root as we only need to find 
+// the minimal distance (and multiply by 256 to increase precision).
+// Needs at least 28-bit signed integers to avoid overflow. 
+static int_least32_t rgb_distance_rmean( uint32_t color, int r2, int g2, int b2 ) {
+  int r1, g1, b1;
+  color_to_rgb(IC_RGB(color),&r1,&g1,&b1);
+  int_least32_t rmean = (r1 + r2) / 2;
+  int_least32_t dr2 = sqr(r1 - r2);
+  int_least32_t dg2 = sqr(g1 - g2);
+  int_least32_t db2 = sqr(b1 - b2);
+  int_least32_t dist = ((512+rmean)*dr2) + 1024*dg2 + ((767-rmean)*db2);    
+  return dist;
+}
+
+// Another approximation to delta-E CIE color distance using
+// simpler calculations. Similar to `rmean` but adds an adjustment factor
+// based on the "red/blue" difference.
+static int_least32_t rgb_distance_rbmean( uint32_t color, int r2, int g2, int b2 ) {
+  int r1, g1, b1;
+  color_to_rgb(IC_RGB(color),&r1,&g1,&b1);
+  int_least32_t rmean = (r1 + r2) / 2;
+  int_least32_t dr2 = sqr(r1 - r2);
+  int_least32_t dg2 = sqr(g1 - g2);
+  int_least32_t db2 = sqr(b1 - b2);
+  int_least32_t dist = 2*dr2 + 4*dg2 + 3*db2 + ((rmean*(dr2 - db2))/256);  
+  return dist;
+}
+
+
+// Maintain a small cache of recently used colors. Should be short enough to be effectively constant time.
+// If we ever use a more expensive color distance method, we may increase the size a bit (64?) 
+// (Initial zero initialized cache is valid.)
+#define RGB_CACHE_LEN (16)
+typedef struct rgb_cache_s {
+  int        last;
+  int        indices[RGB_CACHE_LEN];
+  ic_color_t colors[RGB_CACHE_LEN];
+} rgb_cache_t;
+
+// remember a color in the LRU cache
+void rgb_remember( rgb_cache_t* cache, ic_color_t color, int idx ) {
+  if (cache == NULL) return;
+  cache->colors[cache->last] = color;
+  cache->indices[cache->last] = idx;
+  cache->last++;
+  if (cache->last >= RGB_CACHE_LEN) { cache->last = 0; }
+}
+
+// quick lookup in cache; -1 on failure
+int rgb_lookup( const rgb_cache_t* cache, ic_color_t color ) {
+  if (cache != NULL) {
+    for(int i = 0; i < RGB_CACHE_LEN; i++) {
+      if (cache->colors[i] == color) return cache->indices[i];
+    }
+  }
+  return -1;
+}
+
+// return the index of the closest matching color
+static int rgb_match( uint32_t* palette, int start, int len, rgb_cache_t* cache, ic_color_t color ) {
+  assert(color_is_rgb(color));
+  // in cache?
+  int min = rgb_lookup(cache,color);
+  if (min >= 0) {
+    return min;
+  }
+  // otherwise find closest color match in the palette
+  int r, g, b;
+  color_to_rgb(color,&r,&g,&b);
+  min = start;
+  int_least32_t mindist = (INT_LEAST32_MAX)/4;
+  for(int i = start; i < len; i++) {
+    //int_least32_t dist = rgb_distance_rbmean(palette[i],r,g,b);
+    int_least32_t dist = rgb_distance_rmean(palette[i],r,g,b);
+    if (is_grayish_color(palette[i]) != is_grayish(r, g, b)) { 
+      // with few colors, make it less eager to substitute a gray for a non-gray (or the other way around)
+      if (len <= 16) {
+        dist *= 4;
+      } 
+      else {
+        dist = (dist/4)*5;
+      }
+    } 
+    if (dist < mindist) {
+      min = i;
+      mindist = dist;
+    }
+  }
+  rgb_remember(cache,color,min);
+  return min;
+}
+
+
+// Match RGB to an index in the ANSI 256 color table
+static int rgb_to_ansi256(ic_color_t color) {
+  static rgb_cache_t ansi256_cache;
+  int c = rgb_match(ansi256, 16, 256, &ansi256_cache, color); // not the first 16 ANSI colors as those may be different 
+  //debug_msg("term: rgb %x -> ansi 256: %d\n", color, c );
+  return c;
+}
+
+// Match RGB to an ANSI 16 color code (30-37, 90-97)
+static int color_to_ansi16(ic_color_t color) {
+  if (!color_is_rgb(color)) {
+    return (int)color;
+  }
+  else {
+    static rgb_cache_t ansi16_cache;
+    int c = rgb_match(ansi256, 0, 16, &ansi16_cache, color);
+    //debug_msg("term: rgb %x -> ansi 16: %d\n", color, c );
+    return (c < 8 ? 30 + c : 90 + c - 8); 
+  }
+}
+
+// Match RGB to an ANSI 16 color code (30-37, 90-97)
+// but assuming the bright colors are simulated using 'bold'.
+static int color_to_ansi8(ic_color_t color) {
+  if (!color_is_rgb(color)) {
+    return (int)color;
+  }
+  else {
+    // match to basic 8 colors first
+    static rgb_cache_t ansi8_cache;
+    int c = 30 + rgb_match(ansi256, 0, 8, &ansi8_cache, color);
+    // and then adjust for brightness
+    int r, g, b;
+    color_to_rgb(color,&r,&g,&b);
+    if (r>=196 || g>=196 || b>=196) c += 60;
+    //debug_msg("term: rgb %x -> ansi 8: %d\n", color, c );
+    return c;
+  }
+}
+
+
+//-------------------------------------------------------------
+// Emit color escape codes based on the terminal capability
+//-------------------------------------------------------------
+
+static void fmt_color_ansi8( char* buf, ssize_t len, ic_color_t color, bool bg ) {
+  int c = color_to_ansi8(color) + (bg ? 10 : 0);
+  if (c >= 90) {
+    snprintf(buf, to_size_t(len), IC_CSI "1;%dm", c - 60);    
+  }
+  else {
+    snprintf(buf, to_size_t(len), IC_CSI "22;%dm", c );  
+  }
+}
+
+static void fmt_color_ansi16( char* buf, ssize_t len, ic_color_t color, bool bg ) {
+  snprintf( buf, to_size_t(len), IC_CSI "%dm", color_to_ansi16(color) + (bg ? 10 : 0) );  
+}
+
+static void fmt_color_ansi256( char* buf, ssize_t len,  ic_color_t color, bool bg ) {
+  if (!color_is_rgb(color)) {
+    fmt_color_ansi16(buf,len,color,bg);
+  }
+  else {
+    snprintf( buf, to_size_t(len), IC_CSI "%d;5;%dm", (bg ? 48 : 38), rgb_to_ansi256(color) );  
+  }
+}
+
+static void fmt_color_rgb( char* buf, ssize_t len, ic_color_t color, bool bg ) {
+  if (!color_is_rgb(color)) {
+    fmt_color_ansi16(buf,len,color,bg);
+  }
+  else {
+    int r,g,b;
+    color_to_rgb(color, &r,&g,&b);
+    snprintf( buf, to_size_t(len), IC_CSI "%d;2;%d;%d;%dm", (bg ? 48 : 38), r, g, b );  
+  }
+}
+
+static void fmt_color_ex(char* buf, ssize_t len, palette_t palette, ic_color_t color, bool bg) {
+  if (color == IC_COLOR_NONE || palette == MONOCHROME) return;
+  if (palette == ANSI8) {
+    fmt_color_ansi8(buf,len,color,bg);
+  }
+  else if (!color_is_rgb(color) || palette == ANSI16) {
+    fmt_color_ansi16(buf,len,color,bg);
+  }
+  else if (palette == ANSI256) {
+    fmt_color_ansi256(buf,len,color,bg);
+  }
+  else {
+    fmt_color_rgb(buf,len,color,bg);
+  }
+}
+
+static void term_color_ex(term_t* term, ic_color_t color, bool bg) {
+  char buf[128+1];
+  fmt_color_ex(buf,128,term->palette,color,bg);
+  term_write(term,buf);
+}
+
+//-------------------------------------------------------------
+// Main API functions
+//-------------------------------------------------------------
+
+ic_private void term_color(term_t* term, ic_color_t color) {
+  term_color_ex(term,color,false);
+}
+
+ic_private void term_bgcolor(term_t* term, ic_color_t color) {
+  term_color_ex(term,color,true);
+}
+
+ic_private void term_append_color(term_t* term, stringbuf_t* sbuf, ic_color_t color) {
+  char buf[128+1];
+  fmt_color_ex(buf,128,term->palette,color,false);
+  sbuf_append(sbuf,buf);
+}
+
+ic_private void term_append_bgcolor(term_t* term, stringbuf_t* sbuf, ic_color_t color) {
+  char buf[128+1];
+  fmt_color_ex(buf, 128, term->palette, color, true);
+  sbuf_append(sbuf, buf);
+}
+
+ic_private int term_get_color_bits(term_t* term) {
+  switch (term->palette) {
+  case MONOCHROME: return 1;
+  case ANSI8:      return 3;
+  case ANSI16:     return 4;
+  case ANSI256:    return 8;
+  case ANSIRGB:    return 24;
+  default:         return 4;
+  }
+}

extern/isocline/src/tty.c

@@ -0,0 +1,889 @@
+/* ----------------------------------------------------------------------------
+  Copyright (c) 2021, Daan Leijen
+  This is free software; you can redistribute it and/or modify it
+  under the terms of the MIT License. A copy of the license can be
+  found in the "LICENSE" file at the root of this distribution.
+-----------------------------------------------------------------------------*/
+#include <string.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <locale.h>
+
+#include "tty.h"
+
+#if defined(_WIN32)
+#include <windows.h>
+#include <io.h>
+#define isatty(fd)     _isatty(fd)
+#define read(fd,s,n)   _read(fd,s,n)
+#define STDIN_FILENO   0
+#if (_WIN32_WINNT < 0x0600)
+WINBASEAPI ULONGLONG WINAPI GetTickCount64(VOID);
+#endif
+#else
+#include <signal.h>
+#include <errno.h>
+#include <unistd.h>
+#include <termios.h>
+#include <sys/ioctl.h>
+#include <sys/select.h>
+#if !defined(FIONREAD)
+#include <fcntl.h>
+#endif
+#endif
+
+#define TTY_PUSH_MAX (32)
+
+struct tty_s {
+  int       fd_in;                  // input handle
+  bool      raw_enabled;            // is raw mode enabled?
+  bool      is_utf8;                // is the input stream in utf-8 mode?
+  bool      has_term_resize_event;  // are resize events generated?
+  bool      term_resize_event;      // did a term resize happen?
+  alloc_t*  mem;                    // memory allocator
+  code_t    pushbuf[TTY_PUSH_MAX];  // push back buffer for full key codes  
+  ssize_t   push_count;               
+  uint8_t   cpushbuf[TTY_PUSH_MAX]; // low level push back buffer for bytes
+  ssize_t   cpush_count;
+  long      esc_initial_timeout;    // initial ms wait to see if ESC starts an escape sequence
+  long      esc_timeout;            // follow up delay for characters in an escape sequence
+  #if defined(_WIN32)               
+  HANDLE    hcon;                   // console input handle
+  DWORD     hcon_orig_mode;         // original console mode
+  #else
+  struct termios  orig_ios;         // original terminal settings
+  struct termios  raw_ios;          // raw terminal settings
+  #endif
+};
+
+
+//-------------------------------------------------------------
+// Forward declarations of platform dependent primitives below
+//-------------------------------------------------------------
+
+ic_private bool tty_readc_noblock(tty_t* tty, uint8_t* c, long timeout_ms);  // does not modify `c` when no input (false is returned)
+
+//-------------------------------------------------------------
+// Key code helpers
+//-------------------------------------------------------------
+
+ic_private bool code_is_ascii_char(code_t c, char* chr ) {
+  if (c >= ' ' && c <= 0x7F) {
+    if (chr != NULL) *chr = (char)c;
+    return true;
+  }
+  else {
+    if (chr != NULL) *chr = 0;
+    return false;
+  }
+}
+
+ic_private bool code_is_unicode(code_t c, unicode_t* uchr) {
+  if (c <= KEY_UNICODE_MAX) {
+    if (uchr != NULL) *uchr = c;
+    return true;
+  }
+  else {
+    if (uchr != NULL) *uchr = 0;
+    return false;
+  }
+}
+
+ic_private bool code_is_virt_key(code_t c ) {
+  return (KEY_NO_MODS(c) <= 0x20 || KEY_NO_MODS(c) >= KEY_VIRT);
+}
+
+
+//-------------------------------------------------------------
+// Read a key code
+//-------------------------------------------------------------
+static code_t modify_code( code_t code );
+
+static code_t tty_read_utf8( tty_t* tty, uint8_t c0 ) {
+  uint8_t buf[5];
+  memset(buf, 0, 5);
+
+  // try to read as many bytes as potentially needed
+  buf[0] = c0;
+  ssize_t count = 1;
+  if (c0 > 0x7F) {
+    if (tty_readc_noblock(tty, buf+count, tty->esc_timeout)) {
+      count++;
+      if (c0 > 0xDF) {
+        if (tty_readc_noblock(tty, buf+count, tty->esc_timeout)) {
+          count++;
+          if (c0 > 0xEF) {
+            if (tty_readc_noblock(tty, buf+count, tty->esc_timeout)) {
+              count++;
+            }
+          }
+        }
+      }
+    }
+  }
+  
+  buf[count] = 0;
+  debug_msg("tty: read utf8: count: %zd: %02x,%02x,%02x,%02x", count, buf[0], buf[1], buf[2], buf[3]);
+
+  // decode the utf8 to unicode
+  ssize_t read = 0;
+  code_t code = key_unicode(unicode_from_qutf8(buf, count, &read));
+
+  // push back unused bytes (in the case of invalid utf8)
+  while (count > read) {
+    count--;
+    if (count >= 0 && count <= 4) {  // to help the static analyzer
+      tty_cpush_char(tty, buf[count]);
+    }
+  }
+  return code;
+}
+
+// pop a code from the pushback buffer.
+static bool tty_code_pop(tty_t* tty, code_t* code);
+
+
+// read a single char/key 
+ic_private bool tty_read_timeout(tty_t* tty, long timeout_ms, code_t* code) 
+{
+  // is there a push_count back code?
+  if (tty_code_pop(tty,code)) {
+    return code;
+  }
+
+  // read a single char/byte from a character stream
+  uint8_t c;
+  if (!tty_readc_noblock(tty, &c, timeout_ms)) return false;
+  
+  if (c == KEY_ESC) {
+    // escape sequence?
+    *code = tty_read_esc(tty, tty->esc_initial_timeout, tty->esc_timeout);
+  }
+  else if (c <= 0x7F) {
+    // ascii
+    *code = key_unicode(c);
+  }
+  else if (tty->is_utf8) {
+    // utf8 sequence
+    *code = tty_read_utf8(tty,c);
+  }
+  else {
+    // c >= 0x80 but tty is not utf8; use raw plane so we can translate it back in the end
+    *code = key_unicode( unicode_from_raw(c) );
+  }
+
+  *code = modify_code(*code);
+  return true;
+}
+
+// Transform virtual keys to be more portable across platforms
+static code_t modify_code( code_t code ) {
+  code_t key  = KEY_NO_MODS(code);
+  code_t mods = KEY_MODS(code);
+  debug_msg( "tty: readc %s%s%s 0x%03x ('%c')\n", 
+              mods&KEY_MOD_SHIFT ? "shift+" : "",  mods&KEY_MOD_CTRL  ? "ctrl+" : "", mods&KEY_MOD_ALT   ? "alt+" : "",
+              key, (key >= ' ' && key <= '~' ? key : ' '));
+
+  // treat KEY_RUBOUT (0x7F) as KEY_BACKSP
+  if (key == KEY_RUBOUT) {
+    code = KEY_BACKSP | mods;
+  }
+  // ctrl+'_' is translated to '\x1F' on Linux, translate it back 
+  else if (key == key_char('\x1F') && (mods & KEY_MOD_ALT) == 0) {
+    key = '_';
+    code = WITH_CTRL(key_char('_'));
+  }
+  // treat ctrl/shift + enter always as KEY_LINEFEED for portability
+  else if (key == KEY_ENTER && (mods == KEY_MOD_SHIFT || mods == KEY_MOD_ALT || mods == KEY_MOD_CTRL)) {
+    code = KEY_LINEFEED;
+  }
+  // treat ctrl+tab always as shift+tab for portability
+  else if (code == WITH_CTRL(KEY_TAB)) {
+    code = KEY_SHIFT_TAB;
+  }
+  // treat ctrl+end/alt+>/alt-down and ctrl+home/alt+</alt-up always as pagedown/pageup for portability
+  else if (code == WITH_ALT(KEY_DOWN) || code == WITH_ALT('>') || code == WITH_CTRL(KEY_END)) {
+    code = KEY_PAGEDOWN;
+  }
+  else if (code == WITH_ALT(KEY_UP) || code == WITH_ALT('<') || code == WITH_CTRL(KEY_HOME)) {
+    code = KEY_PAGEUP;
+  }
+  
+  // treat C0 codes without KEY_MOD_CTRL
+  if (key < ' ' && (mods&KEY_MOD_CTRL) != 0) {
+    code &= ~KEY_MOD_CTRL; 
+  }
+  
+  return code;
+}
+
+
+// read a single char/key 
+ic_private code_t tty_read(tty_t* tty)
+{
+  code_t code;
+  if (!tty_read_timeout(tty, -1, &code)) return KEY_NONE;
+  return code;
+}
+
+//-------------------------------------------------------------
+// Read back an ANSI query response
+//-------------------------------------------------------------
+
+ic_private bool tty_read_esc_response(tty_t* tty, char esc_start, bool final_st, char* buf, ssize_t buflen ) 
+{
+  buf[0] = 0;
+  ssize_t len = 0;
+  uint8_t c = 0;
+  if (!tty_readc_noblock(tty, &c, 2*tty->esc_initial_timeout) || c != '\x1B') {
+    debug_msg("initial esc response failed: 0x%02x\n", c);
+    return false;
+  }
+  if (!tty_readc_noblock(tty, &c, tty->esc_timeout) || (c != esc_start)) return false;
+  while( len < buflen ) {
+    if (!tty_readc_noblock(tty, &c, tty->esc_timeout)) return false;
+    if (final_st) {
+      // OSC is terminated by BELL, or ESC \ (ST)  (and STX)
+      if (c=='\x07' || c=='\x02') {
+        break;
+      }
+      else if (c=='\x1B') {
+        uint8_t c1;
+        if (!tty_readc_noblock(tty, &c1, tty->esc_timeout)) return false;
+        if (c1=='\\') break;
+        tty_cpush_char(tty,c1);
+      }
+    }
+    else {
+      if (c == '\x02') { // STX
+        break;
+      }
+      else if (!((c >= '0' && c <= '9') || strchr("<=>?;:",c) != NULL)) {
+        buf[len++] = (char)c; // for non-OSC save the terminating character
+        break;
+      }
+    }
+    buf[len++] = (char)c; 
+  }
+  buf[len] = 0;
+  debug_msg("tty: escape query response: %s\n", buf);
+  return true;
+}
+
+//-------------------------------------------------------------
+// High level code pushback
+//-------------------------------------------------------------
+
+static bool tty_code_pop( tty_t* tty, code_t* code ) {
+  if (tty->push_count <= 0) return false;
+  tty->push_count--;
+  *code = tty->pushbuf[tty->push_count];
+  return true;
+}
+
+ic_private void tty_code_pushback( tty_t* tty, code_t c ) {   
+  // note: must be signal safe
+  if (tty->push_count >= TTY_PUSH_MAX) return;
+  tty->pushbuf[tty->push_count] = c;
+  tty->push_count++;
+}
+
+
+//-------------------------------------------------------------
+// low-level character pushback (for escape sequences and windows)
+//-------------------------------------------------------------
+
+ic_private bool tty_cpop(tty_t* tty, uint8_t* c) {  
+  if (tty->cpush_count <= 0) {  // do not modify c on failure (see `tty_decode_unicode`)
+    return false;
+  }
+  else {
+    tty->cpush_count--;
+    *c = tty->cpushbuf[tty->cpush_count];
+    return true;
+  }
+}
+
+static void tty_cpush(tty_t* tty, const char* s) {
+  ssize_t len = ic_strlen(s);
+  if (tty->push_count + len > TTY_PUSH_MAX) {
+    debug_msg("tty: cpush buffer full! (pushing %s)\n", s);
+    assert(false);
+    return;
+  }
+  for (ssize_t i = 0; i < len; i++) {
+    tty->cpushbuf[tty->cpush_count + i] = (uint8_t)( s[len - i - 1] );
+  }
+  tty->cpush_count += len;
+  return;
+}
+
+// convenience function for small sequences
+static void tty_cpushf(tty_t* tty, const char* fmt, ...) {
+  va_list args;
+  va_start(args,fmt);
+  char buf[TTY_PUSH_MAX+1];
+  vsnprintf(buf,TTY_PUSH_MAX,fmt,args);
+  buf[TTY_PUSH_MAX] = 0;
+  tty_cpush(tty,buf);
+  va_end(args);
+  return;
+}
+
+ic_private void tty_cpush_char(tty_t* tty, uint8_t c) {  
+  uint8_t buf[2];
+  buf[0] = c;
+  buf[1] = 0;
+  tty_cpush(tty, (const char*)buf);
+}
+
+
+//-------------------------------------------------------------
+// Push escape codes (used on Windows to insert keys)
+//-------------------------------------------------------------
+
+static unsigned csi_mods(code_t mods) {
+  unsigned m = 1;
+  if (mods&KEY_MOD_SHIFT) m += 1;
+  if (mods&KEY_MOD_ALT)   m += 2;
+  if (mods&KEY_MOD_CTRL)  m += 4;
+  return m;
+}
+
+// Push ESC [ <vtcode> ; <mods> ~
+static void tty_cpush_csi_vt( tty_t* tty, code_t mods, uint32_t vtcode ) {
+  tty_cpushf(tty,"\x1B[%u;%u~", vtcode, csi_mods(mods) );
+}
+
+// push ESC [ 1 ; <mods> <xcmd>
+static void tty_cpush_csi_xterm( tty_t* tty, code_t mods, char xcode ) {
+  tty_cpushf(tty,"\x1B[1;%u%c", csi_mods(mods), xcode );
+}
+
+// push ESC [ <unicode> ; <mods> u
+static void tty_cpush_csi_unicode( tty_t* tty, code_t mods, uint32_t unicode ) {
+  if ((unicode < 0x80 && mods == 0) || 
+      (mods == KEY_MOD_CTRL && unicode < ' ' && unicode != KEY_TAB && unicode != KEY_ENTER 
+                        && unicode != KEY_LINEFEED && unicode != KEY_BACKSP) ||
+      (mods == KEY_MOD_SHIFT && unicode >= ' ' && unicode <= KEY_RUBOUT)) {
+    tty_cpush_char(tty,(uint8_t)unicode);
+  }
+  else {
+    tty_cpushf(tty,"\x1B[%u;%uu", unicode, csi_mods(mods) );
+  }
+}
+
+//-------------------------------------------------------------
+// Init
+//-------------------------------------------------------------
+
+static bool tty_init_raw(tty_t* tty);
+static void tty_done_raw(tty_t* tty);
+
+static bool tty_init_utf8(tty_t* tty) {
+  #ifdef _WIN32
+  tty->is_utf8 = true;
+  #else
+  const char* loc = setlocale(LC_ALL,"");
+  tty->is_utf8 = (ic_icontains(loc,"UTF-8") || ic_icontains(loc,"utf8") || ic_stricmp(loc,"C") == 0);
+  debug_msg("tty: utf8: %s (loc=%s)\n", tty->is_utf8 ? "true" : "false", loc);
+  #endif
+  return true;
+}
+
+ic_private tty_t* tty_new(alloc_t* mem, int fd_in) 
+{
+  tty_t* tty = mem_zalloc_tp(mem, tty_t);
+  tty->mem = mem;
+  tty->fd_in = (fd_in < 0 ? STDIN_FILENO : fd_in);
+  #if defined(__APPLE__)
+  tty->esc_initial_timeout = 200;  // apple use ESC+<key> for alt-<key>
+  #else
+  tty->esc_initial_timeout = 100; 
+  #endif
+  tty->esc_timeout = 10;
+  if (!(isatty(tty->fd_in) && tty_init_raw(tty) && tty_init_utf8(tty))) {
+    tty_free(tty);
+    return NULL;
+  }
+  return tty;
+}
+
+ic_private void tty_free(tty_t* tty) {
+  if (tty==NULL) return;
+  tty_end_raw(tty);
+  tty_done_raw(tty);
+  mem_free(tty->mem,tty);
+}
+
+ic_private bool tty_is_utf8(const tty_t* tty) {
+  if (tty == NULL) return true;
+  return (tty->is_utf8);
+}
+
+ic_private bool tty_term_resize_event(tty_t* tty) {
+  if (tty == NULL) return true;
+  if (tty->has_term_resize_event) {
+    if (!tty->term_resize_event) return false;
+    tty->term_resize_event = false;  // reset.   
+  }
+  return true;  // always return true on systems without a resize event (more expensive but still ok)
+}
+
+ic_private void tty_set_esc_delay(tty_t* tty, long initial_delay_ms, long followup_delay_ms) {
+  tty->esc_initial_timeout = (initial_delay_ms < 0 ? 0 : (initial_delay_ms > 1000 ? 1000 : initial_delay_ms));
+  tty->esc_timeout = (followup_delay_ms < 0 ? 0 : (followup_delay_ms > 1000 ? 1000 : followup_delay_ms));
+}
+
+//-------------------------------------------------------------
+// Unix
+//-------------------------------------------------------------
+#if !defined(_WIN32)
+
+static bool tty_readc_blocking(tty_t* tty, uint8_t* c) {
+  if (tty_cpop(tty,c)) return true;
+  *c = 0;
+  ssize_t nread = read(tty->fd_in, (char*)c, 1);
+  if (nread < 0 && errno == EINTR) {
+    // can happen on SIGWINCH signal for terminal resize
+  }
+  return (nread == 1);
+}
+
+
+// non blocking read -- with a small timeout used for reading escape sequences.
+ic_private bool tty_readc_noblock(tty_t* tty, uint8_t* c, long timeout_ms) 
+{
+  // in our pushback buffer?
+  if (tty_cpop(tty, c)) return true;
+
+  // blocking read?
+  if (timeout_ms < 0) {
+    return tty_readc_blocking(tty,c);
+  }
+
+  // if supported, peek first if any char is available.
+  #if defined(FIONREAD)
+  { int navail = 0;
+    if (ioctl(0, FIONREAD, &navail) == 0) {
+      if (navail >= 1) {
+        return tty_readc_blocking(tty, c);
+      }
+      else if (timeout_ms == 0) {
+        return false;  // return early if there is no input available (with a zero timeout)
+      }
+    }
+  }
+  #endif
+
+  // otherwise block for at most timeout milliseconds
+  #if defined(FD_SET)   
+    // we can use select to detect when input becomes available
+    fd_set readset;
+    struct timeval time;
+    FD_ZERO(&readset);
+    FD_SET(tty->fd_in, &readset);
+    time.tv_sec  = (timeout_ms > 0 ? timeout_ms / 1000 : 0);
+    time.tv_usec = (timeout_ms > 0 ? 1000*(timeout_ms % 1000) : 0);      
+    if (select(tty->fd_in + 1, &readset, NULL, NULL, &time) == 1) {
+      // input available
+      return tty_readc_blocking(tty, c);
+    }    
+  #else
+    // no select, we cannot timeout; use usleeps :-(
+    // todo: this seems very rare nowadays; should be even support this?
+    do {
+      // peek ahead if possible
+      #if defined(FIONREAD)
+      int navail = 0;
+      if (ioctl(0, FIONREAD, &navail) == 0 && navail >= 1) {
+        return tty_readc_blocking(tty, c);
+      }
+      #elif defined(O_NONBLOCK)
+      // use a temporary non-blocking read mode
+      int fstatus = fcntl(tty->fd_in, F_GETFL, 0);
+      if (fstatus != -1) {
+        if (fcntl(tty->fd_in, F_SETFL, (fstatus | O_NONBLOCK)) != -1) {
+          char buf[2] = { 0, 0 };
+          ssize_t nread = read(tty->fd_in, buf, 1);
+          fcntl(tty->fd_in, F_SETFL, fstatus);
+          if (nread >= 1) {
+            *c = (uint8_t)buf[0];
+            return true;
+          }
+        }
+      }
+      #else
+      #error "define an nonblocking read for this platform"
+      #endif
+      // and sleep a bit
+      if (timeout_ms > 0) {
+        usleep(50*1000L); // sleep at most 0.05s at a time
+        timeout_ms -= 100;
+        if (timeout_ms < 0) { timeout_ms = 0; }
+      }      
+    } 
+    while (timeout_ms > 0);
+  #endif  
+  return false;
+}
+
+#if defined(TIOCSTI) 
+ic_private bool tty_async_stop(const tty_t* tty) {
+  // insert ^C in the input stream
+  char c = KEY_CTRL_C;
+  return (ioctl(tty->fd_in, TIOCSTI, &c) >= 0);
+}
+#else
+ic_private bool tty_async_stop(const tty_t* tty) {
+  return false;
+}
+#endif
+
+// We install various signal handlers to restore the terminal settings
+// in case of a terminating signal. This is also used to catch terminal window resizes.
+// This is not strictly needed so this can be disabled on 
+// (older) platforms that do not support signal handling well.
+#if defined(SIGWINCH) && defined(SA_RESTART)  // ensure basic signal functionality is defined
+
+// store the tty in a global so we access it on unexpected termination
+static tty_t* sig_tty; // = NULL
+
+// Catch all termination signals (and SIGWINCH)
+typedef struct signal_handler_s {
+  int signum;
+  union {
+    int _avoid_warning;
+    struct sigaction previous;
+  } action;
+} signal_handler_t;
+
+static signal_handler_t sighandlers[] = {
+  { SIGWINCH, {0} },
+  { SIGTERM , {0} }, 
+  { SIGINT  , {0} }, 
+  { SIGQUIT , {0} }, 
+  { SIGHUP  , {0} },
+  { SIGSEGV , {0} }, 
+  { SIGTRAP , {0} }, 
+  { SIGBUS  , {0} }, 
+  { SIGTSTP , {0} },
+  { SIGTTIN , {0} }, 
+  { SIGTTOU , {0} },
+  { 0       , {0} }
+};
+
+static bool sigaction_is_valid( struct sigaction* sa ) {
+  return (sa->sa_sigaction != NULL && sa->sa_handler != SIG_DFL && sa->sa_handler != SIG_IGN);
+}
+
+// Generic signal handler
+static void sig_handler(int signum, siginfo_t* siginfo, void* uap ) {
+  if (signum == SIGWINCH) {
+    if (sig_tty != NULL) {
+      sig_tty->term_resize_event = true;
+    }
+  }
+  else {
+    // the rest are termination signals; restore the terminal mode. (`tcsetattr` is signal-safe)
+    if (sig_tty != NULL && sig_tty->raw_enabled) {
+      tcsetattr(sig_tty->fd_in, TCSAFLUSH, &sig_tty->orig_ios);
+      sig_tty->raw_enabled = false;
+    }
+  }
+  // call previous handler
+  signal_handler_t* sh = sighandlers;
+  while( sh->signum != 0 && sh->signum != signum) { sh++; }
+  if (sh->signum == signum) {
+    if (sigaction_is_valid(&sh->action.previous)) {
+      (sh->action.previous.sa_sigaction)(signum, siginfo, uap);
+    }
+  }
+}
+
+static void signals_install(tty_t* tty) {
+  sig_tty = tty;
+  // generic signal handler
+  struct sigaction handler;
+  memset(&handler,0,sizeof(handler));
+  sigemptyset(&handler.sa_mask);
+  handler.sa_sigaction = &sig_handler; 
+  handler.sa_flags = SA_RESTART;
+  // install for all signals
+  for( signal_handler_t* sh = sighandlers; sh->signum != 0; sh++ ) {
+    if (sigaction( sh->signum, NULL, &sh->action.previous) == 0) {            // get previous
+      if (sh->action.previous.sa_handler != SIG_IGN) {                        // if not to be ignored
+        if (sigaction( sh->signum, &handler, &sh->action.previous ) < 0) {    // install our handler
+          sh->action.previous.sa_sigaction = NULL;       // do not restore on error
+        }
+        else if (sh->signum == SIGWINCH) {
+          sig_tty->has_term_resize_event = true;
+        };
+      }
+    }    
+  }
+}
+
+static void signals_restore(void) {
+  // restore all signal handlers
+  for( signal_handler_t* sh = sighandlers; sh->signum != 0; sh++ ) {
+    if (sigaction_is_valid(&sh->action.previous)) {
+      sigaction( sh->signum, &sh->action.previous, NULL );
+    };
+  }
+  sig_tty = NULL;
+}
+
+#else
+static void signals_install(tty_t* tty) {
+  ic_unused(tty);
+  // nothing
+}
+static void signals_restore(void) {
+  // nothing
+}
+
+#endif
+
+ic_private bool tty_start_raw(tty_t* tty) {
+  if (tty == NULL) return false;
+  if (tty->raw_enabled) return true;
+  if (tcsetattr(tty->fd_in,TCSAFLUSH,&tty->raw_ios) < 0) return false;  
+  tty->raw_enabled = true;
+  return true;
+}
+
+ic_private void tty_end_raw(tty_t* tty) {
+  if (tty == NULL) return;
+  if (!tty->raw_enabled) return;
+  tty->cpush_count = 0;
+  if (tcsetattr(tty->fd_in,TCSAFLUSH,&tty->orig_ios) < 0) return;
+  tty->raw_enabled = false;
+}
+
+static bool tty_init_raw(tty_t* tty) 
+{  
+  // Set input to raw mode. See <https://man7.org/linux/man-pages/man3/termios.3.html>.
+  if (tcgetattr(tty->fd_in,&tty->orig_ios) == -1) return false;
+  tty->raw_ios = tty->orig_ios; 
+  // input: no break signal, no \r to \n, no parity check, no 8-bit to 7-bit, no flow control
+  tty->raw_ios.c_iflag &= ~(unsigned long)(BRKINT | ICRNL | INPCK | ISTRIP | IXON);
+  // control: allow 8-bit
+  tty->raw_ios.c_cflag |= CS8;  
+  // local: no echo, no line-by-line (canonical), no extended input processing, no signals for ^z,^c
+  tty->raw_ios.c_lflag &= ~(unsigned long)(ECHO | ICANON | IEXTEN | ISIG);
+  // 1 byte at a time, no delay
+  tty->raw_ios.c_cc[VTIME] = 0;
+  tty->raw_ios.c_cc[VMIN] = 1;
+
+  // store in global so our signal handlers can restore the terminal mode
+  signals_install(tty);
+  
+  return true;
+}
+
+static void tty_done_raw(tty_t* tty) {
+  ic_unused(tty);
+  signals_restore();
+}
+
+
+#else
+
+//-------------------------------------------------------------
+// Windows
+// For best portability we push CSI escape sequences directly
+// to the character stream (instead of returning key codes).
+//-------------------------------------------------------------
+
+static void tty_waitc_console(tty_t* tty, long timeout_ms);
+
+ic_private bool tty_readc_noblock(tty_t* tty, uint8_t* c, long timeout_ms) {  // don't modify `c` if there is no input
+  // in our pushback buffer?
+  if (tty_cpop(tty, c)) return true;
+  // any events in the input queue?
+  tty_waitc_console(tty, timeout_ms);
+  return tty_cpop(tty, c);
+}
+
+// Read from the console input events and push escape codes into the tty cbuffer.
+static void tty_waitc_console(tty_t* tty, long timeout_ms) 
+{
+  //  wait for a key down event
+  INPUT_RECORD inp;
+	DWORD count;
+  uint32_t surrogate_hi = 0;
+  while (true) {
+    // check if there are events if in non-blocking timeout mode
+    if (timeout_ms >= 0) {
+      // first peek ahead
+      if (!GetNumberOfConsoleInputEvents(tty->hcon, &count)) return;  
+      if (count == 0) {
+        if (timeout_ms == 0) {
+          // out of time
+          return;
+        }
+        else {
+          // wait for input events for at most timeout milli seconds
+          ULONGLONG start_ms = GetTickCount64();
+          DWORD res = WaitForSingleObject(tty->hcon, (DWORD)timeout_ms);
+          switch (res) {
+            case WAIT_OBJECT_0: {
+              // input is available, decrease our timeout
+              ULONGLONG waited_ms = (GetTickCount64() - start_ms);
+              timeout_ms -= (long)waited_ms;
+              if (timeout_ms < 0) {
+                timeout_ms = 0;
+              }
+              break;
+            }
+            case WAIT_TIMEOUT:
+            case WAIT_ABANDONED:
+            case WAIT_FAILED:
+            default: 
+              return;
+          }
+        }
+      }
+    }
+
+    // (blocking) Read from the input
+    if (!ReadConsoleInputW(tty->hcon, &inp, 1, &count)) return;
+    if (count != 1) return;
+
+    // resize event?
+    if (inp.EventType == WINDOW_BUFFER_SIZE_EVENT) {
+      tty->term_resize_event = true;
+      continue;
+    }
+
+    // wait for key down events 
+    if (inp.EventType != KEY_EVENT) continue;
+
+    // the modifier state
+    DWORD modstate = inp.Event.KeyEvent.dwControlKeyState;
+    
+    // we need to handle shift up events separately
+    if (!inp.Event.KeyEvent.bKeyDown && inp.Event.KeyEvent.wVirtualKeyCode == VK_SHIFT) {
+      modstate &= (DWORD)~SHIFT_PRESSED;
+    }
+
+    // ignore AltGr
+    DWORD altgr = LEFT_CTRL_PRESSED | RIGHT_ALT_PRESSED;
+    if ((modstate & altgr) == altgr) { modstate &= ~altgr; }
+
+    
+    // get modifiers
+    code_t mods = 0;
+    if ((modstate & ( RIGHT_CTRL_PRESSED | LEFT_CTRL_PRESSED )) != 0) mods |= KEY_MOD_CTRL;
+    if ((modstate & ( RIGHT_ALT_PRESSED | LEFT_ALT_PRESSED )) != 0)   mods |= KEY_MOD_ALT;
+    if ((modstate & SHIFT_PRESSED) != 0)                              mods |= KEY_MOD_SHIFT;
+
+    // virtual keys
+    uint32_t chr = (uint32_t)inp.Event.KeyEvent.uChar.UnicodeChar;
+    WORD     virt = inp.Event.KeyEvent.wVirtualKeyCode;
+    debug_msg("tty: console %s: %s%s%s virt 0x%04x, chr 0x%04x ('%c')\n", inp.Event.KeyEvent.bKeyDown ? "down" : "up", mods&KEY_MOD_CTRL ? "ctrl-" : "", mods&KEY_MOD_ALT ? "alt-" : "", mods&KEY_MOD_SHIFT ? "shift-" : "", virt, chr, chr);
+
+    // only process keydown events (except for Alt-up which is used for unicode pasting...)
+    if (!inp.Event.KeyEvent.bKeyDown && virt != VK_MENU) {
+			continue;
+		}
+    
+    if (chr == 0) { 
+      switch (virt) {
+        case VK_UP:     tty_cpush_csi_xterm(tty, mods, 'A'); return;
+        case VK_DOWN:   tty_cpush_csi_xterm(tty, mods, 'B'); return;
+        case VK_RIGHT:  tty_cpush_csi_xterm(tty, mods, 'C'); return;
+        case VK_LEFT:   tty_cpush_csi_xterm(tty, mods, 'D'); return;
+        case VK_END:    tty_cpush_csi_xterm(tty, mods, 'F'); return; 
+        case VK_HOME:   tty_cpush_csi_xterm(tty, mods, 'H'); return;
+        case VK_DELETE: tty_cpush_csi_vt(tty,mods,3); return;
+        case VK_PRIOR:  tty_cpush_csi_vt(tty,mods,5); return;   //page up
+        case VK_NEXT:   tty_cpush_csi_vt(tty,mods,6); return;   //page down
+        case VK_TAB:    tty_cpush_csi_unicode(tty,mods,9);  return; 
+        case VK_RETURN: tty_cpush_csi_unicode(tty,mods,13); return;
+        default: {
+          uint32_t vtcode = 0;
+          if (virt >= VK_F1 && virt <= VK_F5) {
+            vtcode = 10 + (virt - VK_F1);
+          }
+          else if (virt >= VK_F6 && virt <= VK_F10) {
+            vtcode = 17 + (virt - VK_F6);
+          }
+          else if (virt >= VK_F11 && virt <= VK_F12) {
+            vtcode = 13 + (virt - VK_F11);
+          }
+          if (vtcode > 0) {
+            tty_cpush_csi_vt(tty,mods,vtcode);
+            return;
+          }
+        }
+      }    
+      // ignore other control keys (shift etc).
+    }
+    // high surrogate pair
+    else if (chr >= 0xD800 && chr <= 0xDBFF) {
+			surrogate_hi = (chr - 0xD800);			
+    }
+    // low surrogate pair
+    else if (chr >= 0xDC00 && chr <= 0xDFFF) {
+			chr = ((surrogate_hi << 10) + (chr - 0xDC00) + 0x10000);
+      tty_cpush_csi_unicode(tty,mods,chr);
+      surrogate_hi = 0;
+      return;
+		}
+    // regular character
+    else {
+      tty_cpush_csi_unicode(tty,mods,chr);
+			return;
+    }
+  }
+}  
+
+ic_private bool tty_async_stop(const tty_t* tty) {
+  // send ^c
+  INPUT_RECORD events[2];
+  memset(events, 0, 2*sizeof(INPUT_RECORD));
+  events[0].EventType = KEY_EVENT;
+  events[0].Event.KeyEvent.bKeyDown = TRUE;
+  events[0].Event.KeyEvent.uChar.AsciiChar = KEY_CTRL_C;
+  events[1] = events[0];
+  events[1].Event.KeyEvent.bKeyDown = FALSE;
+  DWORD nwritten = 0;
+  WriteConsoleInput(tty->hcon, events, 2, &nwritten);
+  return (nwritten == 2);
+}
+
+ic_private bool tty_start_raw(tty_t* tty) {
+  if (tty->raw_enabled) return true;
+  GetConsoleMode(tty->hcon,&tty->hcon_orig_mode);
+  DWORD mode = ENABLE_QUICK_EDIT_MODE   // cut&paste allowed 
+             | ENABLE_WINDOW_INPUT      // to catch resize events 
+             // | ENABLE_VIRTUAL_TERMINAL_INPUT 
+             // | ENABLE_PROCESSED_INPUT
+             ;
+  SetConsoleMode(tty->hcon, mode );
+  tty->raw_enabled = true; 
+  return true; 
+}
+
+ic_private void tty_end_raw(tty_t* tty) {
+  if (!tty->raw_enabled) return;
+  SetConsoleMode(tty->hcon, tty->hcon_orig_mode );
+  tty->raw_enabled = false;
+}
+
+static bool tty_init_raw(tty_t* tty) {
+  tty->hcon = GetStdHandle( STD_INPUT_HANDLE );  
+  tty->has_term_resize_event = true;
+  return true;
+}
+
+static void tty_done_raw(tty_t* tty) {
+  ic_unused(tty);
+}
+
+#endif
+
+

extern/isocline/src/tty.h

@@ -0,0 +1,160 @@
+/* ----------------------------------------------------------------------------
+  Copyright (c) 2021, Daan Leijen
+  This is free software; you can redistribute it and/or modify it
+  under the terms of the MIT License. A copy of the license can be
+  found in the "LICENSE" file at the root of this distribution.
+-----------------------------------------------------------------------------*/
+#pragma once
+#ifndef IC_TTY_H
+#define IC_TTY_H
+
+#include "common.h"
+
+//-------------------------------------------------------------
+// TTY/Keyboard input 
+//-------------------------------------------------------------
+
+// Key code
+typedef uint32_t  code_t;
+
+// TTY interface
+struct tty_s;
+typedef struct tty_s tty_t;
+
+
+ic_private tty_t* tty_new(alloc_t* mem, int fd_in);
+ic_private void   tty_free(tty_t* tty);
+
+ic_private bool   tty_is_utf8(const tty_t* tty);
+ic_private bool   tty_start_raw(tty_t* tty);
+ic_private void   tty_end_raw(tty_t* tty);
+ic_private code_t tty_read(tty_t* tty);
+ic_private bool   tty_read_timeout(tty_t* tty, long timeout_ms, code_t* c );
+
+ic_private void   tty_code_pushback( tty_t* tty, code_t c );
+ic_private bool   code_is_ascii_char(code_t c, char* chr );
+ic_private bool   code_is_unicode(code_t c, unicode_t* uchr);
+ic_private bool   code_is_virt_key(code_t c );
+
+ic_private bool   tty_term_resize_event(tty_t* tty); // did the terminal resize?
+ic_private bool   tty_async_stop(const tty_t* tty);  // unblock the read asynchronously
+ic_private void   tty_set_esc_delay(tty_t* tty, long initial_delay_ms, long followup_delay_ms);
+
+// shared between tty.c and tty_esc.c: low level character push
+ic_private void   tty_cpush_char(tty_t* tty, uint8_t c);
+ic_private bool   tty_cpop(tty_t* tty, uint8_t* c);
+ic_private bool   tty_readc_noblock(tty_t* tty, uint8_t* c, long timeout_ms);
+ic_private code_t tty_read_esc(tty_t* tty, long esc_initial_timeout, long esc_timeout); // in tty_esc.c
+
+// used by term.c to read back ANSI escape responses
+ic_private bool   tty_read_esc_response(tty_t* tty, char esc_start, bool final_st, char* buf, ssize_t buflen ); 
+
+
+//-------------------------------------------------------------
+// Key codes: a code_t is 32 bits.
+// we use the bottom 24 (nah, 21) bits for unicode (up to x0010FFFF)
+// The codes after x01000000 are for virtual keys 
+// and events use  x02000000.
+// The top 4 bits are used for modifiers.
+//-------------------------------------------------------------
+
+static inline code_t key_char( char c ) {
+  // careful about signed character conversion (negative char ~> 0x80 - 0xFF)
+  return ((uint8_t)c);
+}
+
+static inline code_t key_unicode( unicode_t u ) {
+  return u;
+}
+
+
+#define KEY_MOD_SHIFT     (0x10000000U)
+#define KEY_MOD_ALT       (0x20000000U)
+#define KEY_MOD_CTRL      (0x40000000U)
+
+#define KEY_NO_MODS(k)    (k & 0x0FFFFFFFU)
+#define KEY_MODS(k)       (k & 0xF0000000U)
+
+#define WITH_SHIFT(x)     (x | KEY_MOD_SHIFT)
+#define WITH_ALT(x)       (x | KEY_MOD_ALT)
+#define WITH_CTRL(x)      (x | KEY_MOD_CTRL)
+
+#define KEY_NONE          (0)
+#define KEY_CTRL_A        (1)
+#define KEY_CTRL_B        (2)
+#define KEY_CTRL_C        (3)
+#define KEY_CTRL_D        (4)
+#define KEY_CTRL_E        (5)
+#define KEY_CTRL_F        (6)
+#define KEY_BELL          (7)
+#define KEY_BACKSP        (8)
+#define KEY_TAB           (9)
+#define KEY_LINEFEED      (10)   // ctrl/shift + enter is considered KEY_LINEFEED
+#define KEY_CTRL_K        (11)
+#define KEY_CTRL_L        (12)
+#define KEY_ENTER         (13)
+#define KEY_CTRL_N        (14)
+#define KEY_CTRL_O        (15)
+#define KEY_CTRL_P        (16)
+#define KEY_CTRL_Q        (17)
+#define KEY_CTRL_R        (18)
+#define KEY_CTRL_S        (19)
+#define KEY_CTRL_T        (20)
+#define KEY_CTRL_U        (21)
+#define KEY_CTRL_V        (22)
+#define KEY_CTRL_W        (23)
+#define KEY_CTRL_X        (24)
+#define KEY_CTRL_Y        (25)
+#define KEY_CTRL_Z        (26)
+#define KEY_ESC           (27)
+#define KEY_SPACE         (32)
+#define KEY_RUBOUT        (127)  // always translated to KEY_BACKSP
+#define KEY_UNICODE_MAX   (0x0010FFFFU)
+
+
+#define KEY_VIRT          (0x01000000U)  
+#define KEY_UP            (KEY_VIRT+0)
+#define KEY_DOWN          (KEY_VIRT+1)
+#define KEY_LEFT          (KEY_VIRT+2)
+#define KEY_RIGHT         (KEY_VIRT+3)
+#define KEY_HOME          (KEY_VIRT+4)
+#define KEY_END           (KEY_VIRT+5)
+#define KEY_DEL           (KEY_VIRT+6)
+#define KEY_PAGEUP        (KEY_VIRT+7)
+#define KEY_PAGEDOWN      (KEY_VIRT+8)
+#define KEY_INS           (KEY_VIRT+9)
+
+#define KEY_F1            (KEY_VIRT+11)
+#define KEY_F2            (KEY_VIRT+12)
+#define KEY_F3            (KEY_VIRT+13)
+#define KEY_F4            (KEY_VIRT+14)
+#define KEY_F5            (KEY_VIRT+15)
+#define KEY_F6            (KEY_VIRT+16)
+#define KEY_F7            (KEY_VIRT+17)
+#define KEY_F8            (KEY_VIRT+18)
+#define KEY_F9            (KEY_VIRT+19)
+#define KEY_F10           (KEY_VIRT+20)
+#define KEY_F11           (KEY_VIRT+21)
+#define KEY_F12           (KEY_VIRT+22)
+#define KEY_F(n)          (KEY_F1 + (n) - 1)
+
+#define KEY_EVENT_BASE    (0x02000000U)
+#define KEY_EVENT_RESIZE  (KEY_EVENT_BASE+1)
+#define KEY_EVENT_AUTOTAB (KEY_EVENT_BASE+2)
+#define KEY_EVENT_STOP    (KEY_EVENT_BASE+3)
+
+// Convenience
+#define KEY_CTRL_UP       (WITH_CTRL(KEY_UP))
+#define KEY_CTRL_DOWN     (WITH_CTRL(KEY_DOWN))
+#define KEY_CTRL_LEFT     (WITH_CTRL(KEY_LEFT))
+#define KEY_CTRL_RIGHT    (WITH_CTRL(KEY_RIGHT))
+#define KEY_CTRL_HOME     (WITH_CTRL(KEY_HOME))
+#define KEY_CTRL_END      (WITH_CTRL(KEY_END))
+#define KEY_CTRL_DEL      (WITH_CTRL(KEY_DEL))
+#define KEY_CTRL_PAGEUP   (WITH_CTRL(KEY_PAGEUP))
+#define KEY_CTRL_PAGEDOWN (WITH_CTRL(KEY_PAGEDOWN)))
+#define KEY_CTRL_INS      (WITH_CTRL(KEY_INS))
+
+#define KEY_SHIFT_TAB     (WITH_SHIFT(KEY_TAB))
+
+#endif // IC_TTY_H

extern/isocline/src/tty_esc.c

@@ -0,0 +1,401 @@
+/* ----------------------------------------------------------------------------
+  Copyright (c) 2021, Daan Leijen
+  This is free software; you can redistribute it and/or modify it
+  under the terms of the MIT License. A copy of the license can be
+  found in the "LICENSE" file at the root of this distribution.
+-----------------------------------------------------------------------------*/
+#include <string.h>
+#include "tty.h"
+
+/*-------------------------------------------------------------
+Decoding escape sequences to key codes.
+This is a bit tricky there are many variants to encode keys as escape sequences, see for example:
+- <http://www.leonerd.org.uk/hacks/fixterms/>.
+- <https://en.wikipedia.org/wiki/ANSI_escape_code#CSI_(Control_Sequence_Introducer)_sequences>
+- <https://www.xfree86.org/current/ctlseqs.html>
+- <https://vt100.net/docs/vt220-rm/contents.html>
+- <https://www.ecma-international.org/wp-content/uploads/ECMA-48_5th_edition_june_1991.pdf>
+
+Generally, for our purposes we accept a subset of escape sequences as:
+
+  escseq ::= ESC 
+          |  ESC char
+          |  ESC start special? (number (';' modifiers)?)? final
+
+where:
+  char         ::= [\x00-\xFF]               # any character
+  special      ::= [:<=>?]             
+  number       ::= [0-9+]
+  modifiers    ::= [1-9]      
+  intermediate ::= [\x20-\x2F]               # !"#$%&'()*+,-./
+  final        ::= [\x40-\x7F]               # @A–Z[\]^_`a–z{|}~
+  ESC          ::= '\x1B'
+  CSI          ::= ESC '['
+  SS3          ::= ESC 'O'
+
+In ECMA48 `special? (number (';' modifiers)?)?` is the more liberal `[\x30-\x3F]*` 
+but that seems never used for key codes. If the number (vtcode or unicode) or the 
+modifiers are not given, we assume these are '1'. 
+We then accept the following key sequences:
+
+  key ::= ESC                                              # lone ESC
+       |  ESC char                                         # Alt+char
+       |  ESC '[' special? vtcode  ';' modifiers '~'       # vt100 codes
+       |  ESC '[' special? '1'     ';' modifiers [A-Z]     # xterm codes
+       |  ESC 'O' special? '1'     ';' modifiers [A-Za-z]  # SS3 codes
+       |  ESC '[' special? unicode ';' modifiers 'u'       # direct unicode code
+
+Moreover, we translate the following special cases that do not fit into the above grammar.
+First we translate away special starter sequences:
+---------------------------------------------------------------------
+  ESC '[' '[' ..      ~>  ESC '[' ..                  # Linux sometimes uses extra '[' for CSI
+  ESC '[' 'O' ..      ~>  ESC 'O' ..                  # Linux sometimes uses extra '[' for SS3
+  ESC 'o' ..          ~>  ESC 'O' ..                  # Eterm: ctrl + SS3
+  ESC '?' ..          ~>  ESC 'O' ..                  # vt52 treated as SS3
+
+And then translate the following special cases into a standard form:
+---------------------------------------------------------------------
+  ESC '[' .. '@'      ~>  ESC '[' '3' '~'             # Del on Mach
+  ESC '[' .. '9'      ~>  ESC '[' '2' '~'             # Ins on Mach
+  ESC .. [^@$]        ~>  ESC .. '~'                  # ETerm,xrvt,urxt: ^ = ctrl, $ = shift, @ = alt
+  ESC '[' [a-d]       ~>  ESC '[' '1' ';' '2' [A-D]   # Eterm shift+<cursor>
+  ESC 'O' [1-9] final ~>  ESC 'O' '1' ';' [1-9] final # modifiers as parameter 1 (like on Haiku)
+  ESC '[' [1-9] [^~u] ~>  ESC 'O' '1' ';' [1-9] final # modifiers as parameter 1
+
+The modifier keys are encoded as "(modifiers-1) & mask" where the 
+shift mask is 0x01, alt 0x02 and ctrl 0x04. Therefore:
+------------------------------------------------------------
+  1:  -           5: ctrl            9: alt  (for minicom)
+  2:  shift       6: shift+ctrl
+  3:  alt         7: alt+ctrl
+  4:  shift+alt   8: shift+alt+ctrl
+
+The different encodings fox vt100, xterm, and SS3 are:
+
+vt100:  ESC [ vtcode ';' modifiers '~'
+--------------------------------------
+  1:  Home       10-15: F1-F5
+  2:  Ins        16   : F5
+  3:  Del        17-21: F6-F10
+  4:  End        23-26: F11-F14
+  5:  PageUp     28   : F15
+  6:  PageDn     29   : F16
+  7:  Home       31-34: F17-F20
+  8:  End
+
+xterm: ESC [ 1 ';' modifiers [A-Z]
+-----------------------------------
+  A: Up          N: F2        
+  B: Down        O: F3       
+  C: Right       P: F4       
+  D: Left        Q: F5       
+  E: '5'         R: F6       
+  F: End         S: F7       
+  G:             T: F8       
+  H: Home        U: PageDn       
+  I: PageUp      V: PageUp       
+  J:             W: F11      
+  K:             X: F12      
+  L: Ins         Y: End      
+  M: F1          Z: shift+Tab
+
+SS3:   ESC 'O' 1 ';' modifiers [A-Za-z]
+---------------------------------------
+  (normal)                       (numpad)
+  A: Up          N:              a: Up        n:           
+  B: Down        O:              b: Down      o: 
+  C: Right       P: F1           c: Right     p: Ins  
+  D: Left        Q: F2           d: Left      q: End  
+  E: '5'         R: F3           e:           r: Down 
+  F: End         S: F4           f:           s: PageDn
+  G:             T: F5           g:           t: Left 
+  H: Home        U: F6           h:           u: '5'
+  I: Tab         V: F7           i:           v: Right
+  J:             W: F8           j: '*'       w: Home 
+  K:             X: F9           k: '+'       x: Up 
+  L:             Y: F10          l: ','       y: PageUp 
+  M: \x0A '\n'   Z: shift+Tab    m: '-'       z:  
+    
+-------------------------------------------------------------*/
+
+//-------------------------------------------------------------
+// Decode escape sequences
+//-------------------------------------------------------------
+
+static code_t esc_decode_vt(uint32_t vt_code ) {
+  switch(vt_code) {
+    case 1: return KEY_HOME; 
+    case 2: return KEY_INS;
+    case 3: return KEY_DEL;
+    case 4: return KEY_END;          
+    case 5: return KEY_PAGEUP;
+    case 6: return KEY_PAGEDOWN;
+    case 7: return KEY_HOME;
+    case 8: return KEY_END;          
+    default: 
+      if (vt_code >= 10 && vt_code <= 15) return KEY_F(1  + (vt_code - 10));
+      if (vt_code == 16) return KEY_F5; // minicom
+      if (vt_code >= 17 && vt_code <= 21) return KEY_F(6  + (vt_code - 17));
+      if (vt_code >= 23 && vt_code <= 26) return KEY_F(11 + (vt_code - 23));
+      if (vt_code >= 28 && vt_code <= 29) return KEY_F(15 + (vt_code - 28));
+      if (vt_code >= 31 && vt_code <= 34) return KEY_F(17 + (vt_code - 31));
+  }
+  return KEY_NONE;
+}
+
+static code_t esc_decode_xterm( uint8_t xcode ) {
+  // ESC [
+  switch(xcode) {
+    case 'A': return KEY_UP;
+    case 'B': return KEY_DOWN;
+    case 'C': return KEY_RIGHT;
+    case 'D': return KEY_LEFT;
+    case 'E': return '5';          // numpad 5
+    case 'F': return KEY_END;
+    case 'H': return KEY_HOME;
+    case 'Z': return KEY_TAB | KEY_MOD_SHIFT;
+    // Freebsd:
+    case 'I': return KEY_PAGEUP;  
+    case 'L': return KEY_INS;   
+    case 'M': return KEY_F1;
+    case 'N': return KEY_F2;
+    case 'O': return KEY_F3;
+    case 'P': return KEY_F4;       // note: differs from <https://en.wikipedia.org/wiki/ANSI_escape_code#CSI_(Control_Sequence_Introducer)_sequences>
+    case 'Q': return KEY_F5;
+    case 'R': return KEY_F6;
+    case 'S': return KEY_F7;
+    case 'T': return KEY_F8;
+    case 'U': return KEY_PAGEDOWN; // Mach
+    case 'V': return KEY_PAGEUP;   // Mach
+    case 'W': return KEY_F11;
+    case 'X': return KEY_F12;    
+    case 'Y': return KEY_END;      // Mach       
+  }
+  return KEY_NONE;
+}
+
+static code_t esc_decode_ss3( uint8_t ss3_code ) {
+  // ESC O 
+  switch(ss3_code) {
+    case 'A': return KEY_UP;
+    case 'B': return KEY_DOWN;
+    case 'C': return KEY_RIGHT;
+    case 'D': return KEY_LEFT;
+    case 'E': return '5';           // numpad 5
+    case 'F': return KEY_END;
+    case 'H': return KEY_HOME;
+    case 'I': return KEY_TAB;
+    case 'Z': return KEY_TAB | KEY_MOD_SHIFT;
+    case 'M': return KEY_LINEFEED; 
+    case 'P': return KEY_F1;
+    case 'Q': return KEY_F2;
+    case 'R': return KEY_F3;
+    case 'S': return KEY_F4;
+    // on Mach
+    case 'T': return KEY_F5;
+    case 'U': return KEY_F6;
+    case 'V': return KEY_F7;
+    case 'W': return KEY_F8;
+    case 'X': return KEY_F9;  // '=' on vt220
+    case 'Y': return KEY_F10;
+    // numpad
+    case 'a': return KEY_UP;
+    case 'b': return KEY_DOWN;
+    case 'c': return KEY_RIGHT;
+    case 'd': return KEY_LEFT;
+    case 'j': return '*';
+    case 'k': return '+';
+    case 'l': return ',';
+    case 'm': return '-'; 
+    case 'n': return KEY_DEL; // '.'
+    case 'o': return '/'; 
+    case 'p': return KEY_INS;
+    case 'q': return KEY_END;  
+    case 'r': return KEY_DOWN; 
+    case 's': return KEY_PAGEDOWN; 
+    case 't': return KEY_LEFT; 
+    case 'u': return '5';
+    case 'v': return KEY_RIGHT;
+    case 'w': return KEY_HOME;  
+    case 'x': return KEY_UP; 
+    case 'y': return KEY_PAGEUP;   
+  }
+  return KEY_NONE;
+}
+
+static void tty_read_csi_num(tty_t* tty, uint8_t* ppeek, uint32_t* num, long esc_timeout) {
+  *num = 1; // default
+  ssize_t count = 0;
+  uint32_t i = 0;
+  while (*ppeek >= '0' && *ppeek <= '9' && count < 16) {    
+    uint8_t digit = *ppeek - '0';
+    if (!tty_readc_noblock(tty,ppeek,esc_timeout)) break;  // peek is not modified in this case 
+    count++;
+    i = 10*i + digit; 
+  }
+  if (count > 0) *num = i;
+}
+
+static code_t tty_read_csi(tty_t* tty, uint8_t c1, uint8_t peek, code_t mods0, long esc_timeout) {
+  // CSI starts with 0x9b (c1=='[') | ESC [ (c1=='[') | ESC [Oo?] (c1 == 'O')  /* = SS3 */
+  
+  // check for extra starter '[' (Linux sends ESC [ [ 15 ~  for F5 for example)
+  if (c1 == '[' && strchr("[Oo", (char)peek) != NULL) {
+    uint8_t cx = peek;
+    if (tty_readc_noblock(tty,&peek,esc_timeout)) {
+      c1 = cx;
+    }
+  }
+
+  // "special" characters ('?' is used for private sequences)
+  uint8_t special = 0;
+  if (strchr(":<=>?",(char)peek) != NULL) { 
+    special = peek;
+    if (!tty_readc_noblock(tty,&peek,esc_timeout)) {  
+      tty_cpush_char(tty,special); // recover
+      return (key_unicode(c1) | KEY_MOD_ALT);       // Alt+<anychar>
+    }
+  }
+
+  // up to 2 parameters that default to 1
+  uint32_t num1 = 1;
+  uint32_t num2 = 1;
+  tty_read_csi_num(tty,&peek,&num1,esc_timeout);
+  if (peek == ';') {
+    if (!tty_readc_noblock(tty,&peek,esc_timeout)) return KEY_NONE;
+    tty_read_csi_num(tty,&peek,&num2,esc_timeout);
+  }
+
+  // the final character (we do not allow 'intermediate characters')
+  uint8_t final = peek;
+  code_t  modifiers = mods0;
+
+  debug_msg("tty: escape sequence: ESC %c %c %d;%d %c\n", c1, (special == 0 ? '_' : special), num1, num2, final);
+  
+  // Adjust special cases into standard ones.
+  if ((final == '@' || final == '9') && c1 == '[' && num1 == 1) {
+    // ESC [ @, ESC [ 9  : on Mach
+    if (final == '@')      num1 = 3; // DEL
+    else if (final == '9') num1 = 2; // INS 
+    final = '~';
+  }
+  else if (final == '^' || final == '$' || final == '@') {  
+    // Eterm/rxvt/urxt  
+    if (final=='^') modifiers |= KEY_MOD_CTRL;
+    if (final=='$') modifiers |= KEY_MOD_SHIFT;
+    if (final=='@') modifiers |= KEY_MOD_SHIFT | KEY_MOD_CTRL;
+    final = '~';
+  }
+  else if (c1 == '[' && final >= 'a' && final <= 'd') {  // note: do not catch ESC [ .. u  (for unicode)
+    // ESC [ [a-d]  : on Eterm for shift+ cursor
+    modifiers |= KEY_MOD_SHIFT;
+    final = 'A' + (final - 'a');
+  }
+  
+  if (((c1 == 'O') || (c1=='[' && final != '~' && final != 'u')) &&
+      (num2 == 1 && num1 > 1 && num1 <= 8)) 
+  {
+    // on haiku the modifier can be parameter 1, make it parameter 2 instead
+    num2 = num1;
+    num1 = 1;
+  }
+
+  // parameter 2 determines the modifiers
+  if (num2 > 1 && num2 <= 9) {
+    if (num2 == 9) num2 = 3; // iTerm2 in xterm mode
+    num2--;
+    if (num2 & 0x1) modifiers |= KEY_MOD_SHIFT;
+    if (num2 & 0x2) modifiers |= KEY_MOD_ALT;
+    if (num2 & 0x4) modifiers |= KEY_MOD_CTRL;
+  }
+
+  // and translate
+  code_t code = KEY_NONE;
+  if (final == '~') {
+    // vt codes
+    code = esc_decode_vt(num1);
+  }
+  else if (c1 == '[' && final == 'u') {
+    // unicode
+    code = key_unicode(num1);
+  }
+  else if (c1 == 'O' && ((final >= 'A' && final <= 'Z') || (final >= 'a' && final <= 'z'))) {
+    // ss3
+    code = esc_decode_ss3(final);
+  }
+  else if (num1 == 1 && final >= 'A' && final <= 'Z') {
+    // xterm 
+    code = esc_decode_xterm(final);
+  }
+  else if (c1 == '[' && final == 'R') {
+    // cursor position
+    code = KEY_NONE;
+  }  
+
+  if (code == KEY_NONE && final != 'R') { 
+    debug_msg("tty: ignore escape sequence: ESC %c %zu;%zu %c\n", c1, num1, num2, final); 
+  }
+  return (code != KEY_NONE ? (code | modifiers) : KEY_NONE);
+}
+
+static code_t tty_read_osc( tty_t* tty, uint8_t* ppeek, long esc_timeout ) {
+  debug_msg("discard OSC response..\n");
+  // keep reading until termination: OSC is terminated by BELL, or ESC \ (ST)  (and STX)
+  while (true) {
+    uint8_t c = *ppeek;
+    if (c <= '\x07') {  // BELL and anything below (STX, ^C, ^D)
+      if (c != '\x07') { tty_cpush_char( tty, c ); }
+      break;
+    }
+    else if (c=='\x1B') {
+      uint8_t c1;
+      if (!tty_readc_noblock(tty, &c1, esc_timeout)) break;
+      if (c1=='\\') break;
+      tty_cpush_char(tty,c1);
+    }
+    if (!tty_readc_noblock(tty, ppeek, esc_timeout)) break;
+  }
+  return KEY_NONE;
+}
+
+ic_private code_t tty_read_esc(tty_t* tty, long esc_initial_timeout, long esc_timeout) {
+  code_t  mods = 0;
+  uint8_t peek = 0;
+  
+  // lone ESC?
+  if (!tty_readc_noblock(tty, &peek, esc_initial_timeout)) return KEY_ESC;
+
+  // treat ESC ESC as Alt modifier (macOS sends ESC ESC [ [A-D] for alt-<cursor>)
+  if (peek == KEY_ESC) {
+    if (!tty_readc_noblock(tty, &peek, esc_timeout)) goto alt;
+    mods |= KEY_MOD_ALT;
+  }
+
+  // CSI ?
+  if (peek == '[') {
+    if (!tty_readc_noblock(tty, &peek, esc_timeout)) goto alt;
+    return tty_read_csi(tty, '[', peek, mods, esc_timeout);  // ESC [ ...
+  }
+
+  // SS3?
+  if (peek == 'O' || peek == 'o' || peek == '?' /*vt52*/) {
+    uint8_t c1 = peek;
+    if (!tty_readc_noblock(tty, &peek, esc_timeout)) goto alt;
+    if (c1 == 'o') { 
+      // ETerm uses this for ctrl+<cursor>
+      mods |= KEY_MOD_CTRL;
+    }
+    // treat all as standard SS3 'O'
+    return tty_read_csi(tty,'O',peek,mods, esc_timeout);  // ESC [Oo?] ...
+  }
+
+  // OSC: we may get a delayed query response; ensure it is ignored
+  if (peek == ']') {
+    if (!tty_readc_noblock(tty, &peek, esc_timeout)) goto alt;
+    return tty_read_osc(tty, &peek, esc_timeout);  // ESC ] ...
+  }
+
+alt:  
+  // Alt+<char>
+  return (key_unicode(peek) | KEY_MOD_ALT);  // ESC <anychar>
+}

extern/isocline/src/undo.c

@@ -0,0 +1,67 @@
+/* ----------------------------------------------------------------------------
+  Copyright (c) 2021, Daan Leijen
+  This is free software; you can redistribute it and/or modify it
+  under the terms of the MIT License. A copy of the license can be
+  found in the "LICENSE" file at the root of this distribution.
+-----------------------------------------------------------------------------*/
+#include <string.h>
+#include <stdio.h>
+
+#include "../include/isocline.h"
+#include "common.h"
+#include "env.h"
+#include "stringbuf.h"
+#include "completions.h"
+#include "undo.h"
+
+
+
+//-------------------------------------------------------------
+// edit state
+//-------------------------------------------------------------
+struct editstate_s {
+  struct editstate_s* next;
+  const char* input;          // input
+  ssize_t     pos;            // cursor position
+};
+
+ic_private void editstate_init( editstate_t** es ) {
+  *es = NULL;
+}
+
+ic_private void editstate_done( alloc_t* mem, editstate_t** es ) {
+  while (*es != NULL) {
+    editstate_t* next = (*es)->next;
+    mem_free(mem, (*es)->input);
+    mem_free(mem, *es );
+    *es = next;
+  }
+  *es = NULL;
+}
+
+ic_private void editstate_capture( alloc_t* mem, editstate_t** es, const char* input, ssize_t pos) {
+  if (input==NULL) input = "";
+  // alloc
+  editstate_t* entry = mem_zalloc_tp(mem, editstate_t);
+  if (entry == NULL) return;
+  // initialize
+  entry->input = mem_strdup( mem, input);
+  entry->pos   = pos;
+  if (entry->input == NULL) { mem_free(mem, entry); return; }
+  // and push
+  entry->next = *es;
+  *es = entry;
+}
+
+// caller should free *input
+ic_private bool editstate_restore( alloc_t* mem, editstate_t** es, const char** input, ssize_t* pos ) {
+  if (*es == NULL) return false;
+  // pop 
+  editstate_t* entry = *es;
+  *es = entry->next;
+  *input = entry->input;
+  *pos = entry->pos;
+  mem_free(mem, entry);
+  return true;
+}
+

extern/isocline/src/undo.h

@@ -0,0 +1,24 @@
+/* ----------------------------------------------------------------------------
+  Copyright (c) 2021, Daan Leijen
+  This is free software; you can redistribute it and/or modify it
+  under the terms of the MIT License. A copy of the license can be
+  found in the "LICENSE" file at the root of this distribution.
+-----------------------------------------------------------------------------*/
+#pragma once
+#ifndef IC_UNDO_H
+#define IC_UNDO_H
+
+#include "common.h"
+
+//-------------------------------------------------------------
+// Edit state
+//-------------------------------------------------------------
+struct editstate_s;
+typedef struct editstate_s editstate_t;
+
+ic_private void editstate_init( editstate_t** es );
+ic_private void editstate_done( alloc_t* mem, editstate_t** es );
+ic_private void editstate_capture( alloc_t* mem, editstate_t** es, const char* input, ssize_t pos);
+ic_private bool editstate_restore( alloc_t* mem, editstate_t** es, const char** input, ssize_t* pos ); // caller needs to free input
+
+#endif // IC_UNDO_H

extern/isocline/src/wcwidth.c

@@ -0,0 +1,292 @@
+// include in "stringbuf.c"
+/*
+ * This is an implementation of wcwidth() and wcswidth() (defined in
+ * IEEE Std 1002.1-2001) for Unicode.
+ *
+ * http://www.opengroup.org/onlinepubs/007904975/functions/wcwidth.html
+ * http://www.opengroup.org/onlinepubs/007904975/functions/wcswidth.html
+ *
+ * In fixed-width output devices, Latin characters all occupy a single
+ * "cell" position of equal width, whereas ideographic CJK characters
+ * occupy two such cells. Interoperability between terminal-line
+ * applications and (teletype-style) character terminals using the
+ * UTF-8 encoding requires agreement on which character should advance
+ * the cursor by how many cell positions. No established formal
+ * standards exist at present on which Unicode character shall occupy
+ * how many cell positions on character terminals. These routines are
+ * a first attempt of defining such behavior based on simple rules
+ * applied to data provided by the Unicode Consortium.
+ *
+ * For some graphical characters, the Unicode standard explicitly
+ * defines a character-cell width via the definition of the East Asian
+ * FullWidth (F), Wide (W), Half-width (H), and Narrow (Na) classes.
+ * In all these cases, there is no ambiguity about which width a
+ * terminal shall use. For characters in the East Asian Ambiguous (A)
+ * class, the width choice depends purely on a preference of backward
+ * compatibility with either historic CJK or Western practice.
+ * Choosing single-width for these characters is easy to justify as
+ * the appropriate long-term solution, as the CJK practice of
+ * displaying these characters as double-width comes from historic
+ * implementation simplicity (8-bit encoded characters were displayed
+ * single-width and 16-bit ones double-width, even for Greek,
+ * Cyrillic, etc.) and not any typographic considerations.
+ *
+ * Much less clear is the choice of width for the Not East Asian
+ * (Neutral) class. Existing practice does not dictate a width for any
+ * of these characters. It would nevertheless make sense
+ * typographically to allocate two character cells to characters such
+ * as for instance EM SPACE or VOLUME INTEGRAL, which cannot be
+ * represented adequately with a single-width glyph. The following
+ * routines at present merely assign a single-cell width to all
+ * neutral characters, in the interest of simplicity. This is not
+ * entirely satisfactory and should be reconsidered before
+ * establishing a formal standard in this area. At the moment, the
+ * decision which Not East Asian (Neutral) characters should be
+ * represented by double-width glyphs cannot yet be answered by
+ * applying a simple rule from the Unicode database content. Setting
+ * up a proper standard for the behavior of UTF-8 character terminals
+ * will require a careful analysis not only of each Unicode character,
+ * but also of each presentation form, something the author of these
+ * routines has avoided to do so far.
+ *
+ * http://www.unicode.org/unicode/reports/tr11/
+ *
+ * Markus Kuhn -- 2007-05-26 (Unicode 5.0)
+ *
+ * Permission to use, copy, modify, and distribute this software
+ * for any purpose and without fee is hereby granted. The author
+ * disclaims all warranties with regard to this software.
+ *
+ * Latest version: http://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c
+ */
+
+#include <stdint.h>
+#include <string.h>
+
+struct interval {
+	int32_t first;
+	int32_t last;
+};
+
+/* auxiliary function for binary search in interval table */
+static int bisearch(int32_t ucs, const struct interval *table, int max) {
+	int min = 0;
+	int mid;
+
+	if (ucs < table[0].first || ucs > table[max].last)
+		return 0;
+	while (max >= min) {
+		mid = (min + max) / 2;
+		if (ucs > table[mid].last)
+			min = mid + 1;
+		else if (ucs < table[mid].first)
+			max = mid - 1;
+		else
+			return 1;
+	}
+
+	return 0;
+}
+
+
+/* The following two functions define the column width of an ISO 10646
+ * character as follows:
+ *
+ *		- The null character (U+0000) has a column width of 0.
+ *
+ *		- Other C0/C1 control characters and DEL will lead to a return
+ *			value of -1.
+ *
+ *		- Non-spacing and enclosing combining characters (general
+ *			category code Mn or Me in the Unicode database) have a
+ *			column width of 0.
+ *
+ *		- SOFT HYPHEN (U+00AD) has a column width of 1.
+ *
+ *		- Other format characters (general category code Cf in the Unicode
+ *			database) and ZERO WIDTH SPACE (U+200B) have a column width of 0.
+ *
+ *		- Hangul Jamo medial vowels and final consonants (U+1160-U+11FF)
+ *			have a column width of 0.
+ *
+ *		- Spacing characters in the East Asian Wide (W) or East Asian
+ *			Full-width (F) category as defined in Unicode Technical
+ *			Report #11 have a column width of 2.
+ *
+ *		- All remaining characters (including all printable
+ *			ISO 8859-1 and WGL4 characters, Unicode control characters,
+ *			etc.) have a column width of 1.
+ *
+ * This implementation assumes that wchar_t characters are encoded
+ * in ISO 10646.
+ */
+
+static int mk_is_wide_char(int32_t ucs) {
+  static const struct interval wide[] = {
+    {0x1100, 0x115f}, {0x231a, 0x231b}, {0x2329, 0x232a},
+    {0x23e9, 0x23ec}, {0x23f0, 0x23f0}, {0x23f3, 0x23f3},
+    {0x25fd, 0x25fe}, {0x2614, 0x2615}, {0x2648, 0x2653},
+    {0x267f, 0x267f}, {0x2693, 0x2693}, {0x26a1, 0x26a1},
+    {0x26aa, 0x26ab}, {0x26bd, 0x26be}, {0x26c4, 0x26c5},
+    {0x26ce, 0x26ce}, {0x26d4, 0x26d4}, {0x26ea, 0x26ea},
+    {0x26f2, 0x26f3}, {0x26f5, 0x26f5}, {0x26fa, 0x26fa},
+    {0x26fd, 0x26fd}, {0x2705, 0x2705}, {0x270a, 0x270b},
+    {0x2728, 0x2728}, {0x274c, 0x274c}, {0x274e, 0x274e},
+    {0x2753, 0x2755}, {0x2757, 0x2757}, {0x2795, 0x2797},
+    {0x27b0, 0x27b0}, {0x27bf, 0x27bf}, {0x2b1b, 0x2b1c},
+    {0x2b50, 0x2b50}, {0x2b55, 0x2b55}, {0x2e80, 0x2fdf},
+    {0x2ff0, 0x303e}, {0x3040, 0x3247}, {0x3250, 0x4dbf},
+    {0x4e00, 0xa4cf}, {0xa960, 0xa97f}, {0xac00, 0xd7a3},
+    {0xf900, 0xfaff}, {0xfe10, 0xfe19}, {0xfe30, 0xfe6f},
+    {0xff01, 0xff60}, {0xffe0, 0xffe6}, {0x16fe0, 0x16fe1},
+    {0x17000, 0x18aff}, {0x1b000, 0x1b12f}, {0x1b170, 0x1b2ff},
+    {0x1f004, 0x1f004}, {0x1f0cf, 0x1f0cf}, {0x1f18e, 0x1f18e},
+    {0x1f191, 0x1f19a}, {0x1f200, 0x1f202}, {0x1f210, 0x1f23b},
+    {0x1f240, 0x1f248}, {0x1f250, 0x1f251}, {0x1f260, 0x1f265},
+    {0x1f300, 0x1f320}, {0x1f32d, 0x1f335}, {0x1f337, 0x1f37c},
+    {0x1f37e, 0x1f393}, {0x1f3a0, 0x1f3ca}, {0x1f3cf, 0x1f3d3},
+    {0x1f3e0, 0x1f3f0}, {0x1f3f4, 0x1f3f4}, {0x1f3f8, 0x1f43e},
+    {0x1f440, 0x1f440}, {0x1f442, 0x1f4fc}, {0x1f4ff, 0x1f53d},
+    {0x1f54b, 0x1f54e}, {0x1f550, 0x1f567}, {0x1f57a, 0x1f57a},
+    {0x1f595, 0x1f596}, {0x1f5a4, 0x1f5a4}, {0x1f5fb, 0x1f64f},
+    {0x1f680, 0x1f6c5}, {0x1f6cc, 0x1f6cc}, {0x1f6d0, 0x1f6d2},
+    {0x1f6eb, 0x1f6ec}, {0x1f6f4, 0x1f6f8}, {0x1f910, 0x1f93e},
+    {0x1f940, 0x1f94c}, {0x1f950, 0x1f96b}, {0x1f980, 0x1f997},
+    {0x1f9c0, 0x1f9c0}, {0x1f9d0, 0x1f9e6}, {0x20000, 0x2fffd},
+    {0x30000, 0x3fffd},
+  };
+
+  if ( bisearch(ucs, wide, sizeof(wide) / sizeof(struct interval) - 1) ) {
+    return 1;
+	}
+
+  return 0;
+}
+
+static int mk_wcwidth(int32_t ucs) {
+	/* sorted list of non-overlapping intervals of non-spacing characters */
+	/* generated by "uniset +cat=Me +cat=Mn +cat=Cf -00AD +1160-11FF +200B c" */
+	static const struct interval combining[] = {
+    {0x00ad, 0x00ad}, {0x0300, 0x036f}, {0x0483, 0x0489},
+    {0x0591, 0x05bd}, {0x05bf, 0x05bf}, {0x05c1, 0x05c2},
+    {0x05c4, 0x05c5}, {0x05c7, 0x05c7}, {0x0610, 0x061a},
+    {0x061c, 0x061c}, {0x064b, 0x065f}, {0x0670, 0x0670},
+    {0x06d6, 0x06dc}, {0x06df, 0x06e4}, {0x06e7, 0x06e8},
+    {0x06ea, 0x06ed}, {0x0711, 0x0711}, {0x0730, 0x074a},
+    {0x07a6, 0x07b0}, {0x07eb, 0x07f3}, {0x0816, 0x0819},
+    {0x081b, 0x0823}, {0x0825, 0x0827}, {0x0829, 0x082d},
+    {0x0859, 0x085b}, {0x08d4, 0x08e1}, {0x08e3, 0x0902},
+    {0x093a, 0x093a}, {0x093c, 0x093c}, {0x0941, 0x0948},
+    {0x094d, 0x094d}, {0x0951, 0x0957}, {0x0962, 0x0963},
+    {0x0981, 0x0981}, {0x09bc, 0x09bc}, {0x09c1, 0x09c4},
+    {0x09cd, 0x09cd}, {0x09e2, 0x09e3}, {0x0a01, 0x0a02},
+    {0x0a3c, 0x0a3c}, {0x0a41, 0x0a42}, {0x0a47, 0x0a48},
+    {0x0a4b, 0x0a4d}, {0x0a51, 0x0a51}, {0x0a70, 0x0a71},
+    {0x0a75, 0x0a75}, {0x0a81, 0x0a82}, {0x0abc, 0x0abc},
+    {0x0ac1, 0x0ac5}, {0x0ac7, 0x0ac8}, {0x0acd, 0x0acd},
+    {0x0ae2, 0x0ae3}, {0x0afa, 0x0aff}, {0x0b01, 0x0b01},
+    {0x0b3c, 0x0b3c}, {0x0b3f, 0x0b3f}, {0x0b41, 0x0b44},
+    {0x0b4d, 0x0b4d}, {0x0b56, 0x0b56}, {0x0b62, 0x0b63},
+    {0x0b82, 0x0b82}, {0x0bc0, 0x0bc0}, {0x0bcd, 0x0bcd},
+    {0x0c00, 0x0c00}, {0x0c3e, 0x0c40}, {0x0c46, 0x0c48},
+    {0x0c4a, 0x0c4d}, {0x0c55, 0x0c56}, {0x0c62, 0x0c63},
+    {0x0c81, 0x0c81}, {0x0cbc, 0x0cbc}, {0x0cbf, 0x0cbf},
+    {0x0cc6, 0x0cc6}, {0x0ccc, 0x0ccd}, {0x0ce2, 0x0ce3},
+    {0x0d00, 0x0d01}, {0x0d3b, 0x0d3c}, {0x0d41, 0x0d44},
+    {0x0d4d, 0x0d4d}, {0x0d62, 0x0d63}, {0x0dca, 0x0dca},
+    {0x0dd2, 0x0dd4}, {0x0dd6, 0x0dd6}, {0x0e31, 0x0e31},
+    {0x0e34, 0x0e3a}, {0x0e47, 0x0e4e}, {0x0eb1, 0x0eb1},
+    {0x0eb4, 0x0eb9}, {0x0ebb, 0x0ebc}, {0x0ec8, 0x0ecd},
+    {0x0f18, 0x0f19}, {0x0f35, 0x0f35}, {0x0f37, 0x0f37},
+    {0x0f39, 0x0f39}, {0x0f71, 0x0f7e}, {0x0f80, 0x0f84},
+    {0x0f86, 0x0f87}, {0x0f8d, 0x0f97}, {0x0f99, 0x0fbc},
+    {0x0fc6, 0x0fc6}, {0x102d, 0x1030}, {0x1032, 0x1037},
+    {0x1039, 0x103a}, {0x103d, 0x103e}, {0x1058, 0x1059},
+    {0x105e, 0x1060}, {0x1071, 0x1074}, {0x1082, 0x1082},
+    {0x1085, 0x1086}, {0x108d, 0x108d}, {0x109d, 0x109d},
+    {0x1160, 0x11ff}, {0x135d, 0x135f}, {0x1712, 0x1714},
+    {0x1732, 0x1734}, {0x1752, 0x1753}, {0x1772, 0x1773},
+    {0x17b4, 0x17b5}, {0x17b7, 0x17bd}, {0x17c6, 0x17c6},
+    {0x17c9, 0x17d3}, {0x17dd, 0x17dd}, {0x180b, 0x180e},
+    {0x1885, 0x1886}, {0x18a9, 0x18a9}, {0x1920, 0x1922},
+    {0x1927, 0x1928}, {0x1932, 0x1932}, {0x1939, 0x193b},
+    {0x1a17, 0x1a18}, {0x1a1b, 0x1a1b}, {0x1a56, 0x1a56},
+    {0x1a58, 0x1a5e}, {0x1a60, 0x1a60}, {0x1a62, 0x1a62},
+    {0x1a65, 0x1a6c}, {0x1a73, 0x1a7c}, {0x1a7f, 0x1a7f},
+    {0x1ab0, 0x1abe}, {0x1b00, 0x1b03}, {0x1b34, 0x1b34},
+    {0x1b36, 0x1b3a}, {0x1b3c, 0x1b3c}, {0x1b42, 0x1b42},
+    {0x1b6b, 0x1b73}, {0x1b80, 0x1b81}, {0x1ba2, 0x1ba5},
+    {0x1ba8, 0x1ba9}, {0x1bab, 0x1bad}, {0x1be6, 0x1be6},
+    {0x1be8, 0x1be9}, {0x1bed, 0x1bed}, {0x1bef, 0x1bf1},
+    {0x1c2c, 0x1c33}, {0x1c36, 0x1c37}, {0x1cd0, 0x1cd2},
+    {0x1cd4, 0x1ce0}, {0x1ce2, 0x1ce8}, {0x1ced, 0x1ced},
+    {0x1cf4, 0x1cf4}, {0x1cf8, 0x1cf9}, {0x1dc0, 0x1df9},
+    {0x1dfb, 0x1dff}, {0x200b, 0x200f}, {0x202a, 0x202e},
+    {0x2060, 0x2064}, {0x2066, 0x206f}, {0x20d0, 0x20f0},
+    {0x2cef, 0x2cf1}, {0x2d7f, 0x2d7f}, {0x2de0, 0x2dff},
+    {0x302a, 0x302d}, {0x3099, 0x309a}, {0xa66f, 0xa672},
+    {0xa674, 0xa67d}, {0xa69e, 0xa69f}, {0xa6f0, 0xa6f1},
+    {0xa802, 0xa802}, {0xa806, 0xa806}, {0xa80b, 0xa80b},
+    {0xa825, 0xa826}, {0xa8c4, 0xa8c5}, {0xa8e0, 0xa8f1},
+    {0xa926, 0xa92d}, {0xa947, 0xa951}, {0xa980, 0xa982},
+    {0xa9b3, 0xa9b3}, {0xa9b6, 0xa9b9}, {0xa9bc, 0xa9bc},
+    {0xa9e5, 0xa9e5}, {0xaa29, 0xaa2e}, {0xaa31, 0xaa32},
+    {0xaa35, 0xaa36}, {0xaa43, 0xaa43}, {0xaa4c, 0xaa4c},
+    {0xaa7c, 0xaa7c}, {0xaab0, 0xaab0}, {0xaab2, 0xaab4},
+    {0xaab7, 0xaab8}, {0xaabe, 0xaabf}, {0xaac1, 0xaac1},
+    {0xaaec, 0xaaed}, {0xaaf6, 0xaaf6}, {0xabe5, 0xabe5},
+    {0xabe8, 0xabe8}, {0xabed, 0xabed}, {0xfb1e, 0xfb1e},
+    {0xfe00, 0xfe0f}, {0xfe20, 0xfe2f}, {0xfeff, 0xfeff},
+    {0xfff9, 0xfffb}, {0x101fd, 0x101fd}, {0x102e0, 0x102e0},
+    {0x10376, 0x1037a}, {0x10a01, 0x10a03}, {0x10a05, 0x10a06},
+    {0x10a0c, 0x10a0f}, {0x10a38, 0x10a3a}, {0x10a3f, 0x10a3f},
+    {0x10ae5, 0x10ae6}, {0x11001, 0x11001}, {0x11038, 0x11046},
+    {0x1107f, 0x11081}, {0x110b3, 0x110b6}, {0x110b9, 0x110ba},
+    {0x11100, 0x11102}, {0x11127, 0x1112b}, {0x1112d, 0x11134},
+    {0x11173, 0x11173}, {0x11180, 0x11181}, {0x111b6, 0x111be},
+    {0x111ca, 0x111cc}, {0x1122f, 0x11231}, {0x11234, 0x11234},
+    {0x11236, 0x11237}, {0x1123e, 0x1123e}, {0x112df, 0x112df},
+    {0x112e3, 0x112ea}, {0x11300, 0x11301}, {0x1133c, 0x1133c},
+    {0x11340, 0x11340}, {0x11366, 0x1136c}, {0x11370, 0x11374},
+    {0x11438, 0x1143f}, {0x11442, 0x11444}, {0x11446, 0x11446},
+    {0x114b3, 0x114b8}, {0x114ba, 0x114ba}, {0x114bf, 0x114c0},
+    {0x114c2, 0x114c3}, {0x115b2, 0x115b5}, {0x115bc, 0x115bd},
+    {0x115bf, 0x115c0}, {0x115dc, 0x115dd}, {0x11633, 0x1163a},
+    {0x1163d, 0x1163d}, {0x1163f, 0x11640}, {0x116ab, 0x116ab},
+    {0x116ad, 0x116ad}, {0x116b0, 0x116b5}, {0x116b7, 0x116b7},
+    {0x1171d, 0x1171f}, {0x11722, 0x11725}, {0x11727, 0x1172b},
+    {0x11a01, 0x11a06}, {0x11a09, 0x11a0a}, {0x11a33, 0x11a38},
+    {0x11a3b, 0x11a3e}, {0x11a47, 0x11a47}, {0x11a51, 0x11a56},
+    {0x11a59, 0x11a5b}, {0x11a8a, 0x11a96}, {0x11a98, 0x11a99},
+    {0x11c30, 0x11c36}, {0x11c38, 0x11c3d}, {0x11c3f, 0x11c3f},
+    {0x11c92, 0x11ca7}, {0x11caa, 0x11cb0}, {0x11cb2, 0x11cb3},
+    {0x11cb5, 0x11cb6}, {0x11d31, 0x11d36}, {0x11d3a, 0x11d3a},
+    {0x11d3c, 0x11d3d}, {0x11d3f, 0x11d45}, {0x11d47, 0x11d47},
+    {0x16af0, 0x16af4}, {0x16b30, 0x16b36}, {0x16f8f, 0x16f92},
+    {0x1bc9d, 0x1bc9e}, {0x1bca0, 0x1bca3}, {0x1d167, 0x1d169},
+    {0x1d173, 0x1d182}, {0x1d185, 0x1d18b}, {0x1d1aa, 0x1d1ad},
+    {0x1d242, 0x1d244}, {0x1da00, 0x1da36}, {0x1da3b, 0x1da6c},
+    {0x1da75, 0x1da75}, {0x1da84, 0x1da84}, {0x1da9b, 0x1da9f},
+    {0x1daa1, 0x1daaf}, {0x1e000, 0x1e006}, {0x1e008, 0x1e018},
+    {0x1e01b, 0x1e021}, {0x1e023, 0x1e024}, {0x1e026, 0x1e02a},
+    {0x1e8d0, 0x1e8d6}, {0x1e944, 0x1e94a}, {0xe0001, 0xe0001},
+    {0xe0020, 0xe007f}, {0xe0100, 0xe01ef},
+	};
+
+	/* test for 8-bit control characters */
+	if ( ucs == 0 ) {
+		return 0;
+	}
+	if ( ( ucs < 32 ) || ( ( ucs >= 0x7f ) && ( ucs < 0xa0 ) ) ) {
+		return -1;
+	}
+
+	/* binary search in table of non-spacing characters */
+	if ( bisearch( ucs, combining, sizeof( combining ) / sizeof( struct interval ) - 1 ) ) {
+		return 0;
+	}
+
+	/* if we arrive here, ucs is not a combining or C0/C1 control character */
+  return ( mk_is_wide_char( ucs ) ? 2 : 1 );
+}
+

tests/Compiler.test.cpp

@@ -611,7 +611,8 @@ TEST_CASE("TableLiteralsIndexConstant")
     CHECK_EQ("\n" + compileFunction0(R"(
         local a, b = "key", "value"
         return {[a] = 42, [b] = 0}
-)"), R"(
+)"),
+        R"(
 NEWTABLE R0 2 0
 LOADN R1 42
 SETTABLEKS R1 R0 K0
@@ -624,7 +625,8 @@ RETURN R0 1
     CHECK_EQ("\n" + compileFunction0(R"(
         local a, b = 1, 2
         return {[a] = 42, [b] = 0}
-)"), R"(
+)"),
+        R"(
 NEWTABLE R0 0 2
 LOADN R1 42
 SETTABLEN R1 R0 1
@@ -789,8 +791,6 @@ RETURN R0 1
 
 TEST_CASE("TableSizePredictionLoop")
 {
-    ScopedFastFlag sff("LuauPredictTableSizeLoop", true);
-
     CHECK_EQ("\n" + compileFunction0(R"(
 local t = {}
 for i=1,4 do
@@ -2827,7 +2827,7 @@ RETURN R1 -1
 
 TEST_CASE("FastcallSelect")
 {
-    ScopedFastFlag sff("LuauCompileSelectBuiltin", true);
+    ScopedFastFlag sff("LuauCompileSelectBuiltin2", true);
 
     // select(_, ...) compiles to a builtin call
     CHECK_EQ("\n" + compileFunction0("return (select('#', ...))"), R"(
@@ -2846,7 +2846,8 @@ for i=1, select('#', ...) do
     sum += select(i, ...)
 end
 return sum
-)"), R"(
+)"),
+        R"(
 LOADN R0 0
 LOADN R3 1
 LOADK R5 K0
@@ -2856,13 +2857,14 @@ GETVARARGS R6 -1
 CALL R4 -1 1
 MOVE R1 R4
 LOADN R2 1
-FORNPREP R1 +7
+FORNPREP R1 +8
-FASTCALL1 57 R3 +3
+FASTCALL1 57 R3 +4
 GETIMPORT R4 2
+MOVE R5 R3
 GETVARARGS R6 -1
 CALL R4 -1 1
 ADD R0 R0 R4
-FORNLOOP R1 -7
+FORNLOOP R1 -8
 RETURN R0 1
 )");
 

tests/Conformance.test.cpp

@@ -492,7 +492,6 @@ TEST_CASE("DateTime")
 
 TEST_CASE("Debug")
 {
-    ScopedFastFlag sffr("LuauBytecodeV2Read", true);
     ScopedFastFlag sffw("LuauBytecodeV2Write", true);
 
     runConformance("debug.lua");

tests/LValue.test.cpp

@@ -38,8 +38,6 @@ TEST_SUITE_BEGIN("LValue");
 
 TEST_CASE("Luau_merge_hashmap_order")
 {
-    ScopedFastFlag sff{"LuauLValueAsKey", true};
-
     std::string a = "a";
     std::string b = "b";
     std::string c = "c";
@@ -58,20 +56,18 @@ TEST_CASE("Luau_merge_hashmap_order")
     TypeArena arena;
     merge(arena, m, other);
 
-    REQUIRE_EQ(3, m.NEW_refinements.size());
+    REQUIRE_EQ(3, m.size());
-    REQUIRE(m.NEW_refinements.count(mkSymbol(a)));
+    REQUIRE(m.count(mkSymbol(a)));
-    REQUIRE(m.NEW_refinements.count(mkSymbol(b)));
+    REQUIRE(m.count(mkSymbol(b)));
-    REQUIRE(m.NEW_refinements.count(mkSymbol(c)));
+    REQUIRE(m.count(mkSymbol(c)));
 
-    CHECK_EQ("string", toString(m.NEW_refinements[mkSymbol(a)]));
+    CHECK_EQ("string", toString(m[mkSymbol(a)]));
-    CHECK_EQ("string", toString(m.NEW_refinements[mkSymbol(b)]));
+    CHECK_EQ("string", toString(m[mkSymbol(b)]));
-    CHECK_EQ("boolean | number", toString(m.NEW_refinements[mkSymbol(c)]));
+    CHECK_EQ("boolean | number", toString(m[mkSymbol(c)]));
 }
 
 TEST_CASE("Luau_merge_hashmap_order2")
 {
-    ScopedFastFlag sff{"LuauLValueAsKey", true};
-
     std::string a = "a";
     std::string b = "b";
     std::string c = "c";
@@ -90,20 +86,18 @@ TEST_CASE("Luau_merge_hashmap_order2")
     TypeArena arena;
     merge(arena, m, other);
 
-    REQUIRE_EQ(3, m.NEW_refinements.size());
+    REQUIRE_EQ(3, m.size());
-    REQUIRE(m.NEW_refinements.count(mkSymbol(a)));
+    REQUIRE(m.count(mkSymbol(a)));
-    REQUIRE(m.NEW_refinements.count(mkSymbol(b)));
+    REQUIRE(m.count(mkSymbol(b)));
-    REQUIRE(m.NEW_refinements.count(mkSymbol(c)));
+    REQUIRE(m.count(mkSymbol(c)));
 
-    CHECK_EQ("string", toString(m.NEW_refinements[mkSymbol(a)]));
+    CHECK_EQ("string", toString(m[mkSymbol(a)]));
-    CHECK_EQ("string", toString(m.NEW_refinements[mkSymbol(b)]));
+    CHECK_EQ("string", toString(m[mkSymbol(b)]));
-    CHECK_EQ("boolean | number", toString(m.NEW_refinements[mkSymbol(c)]));
+    CHECK_EQ("boolean | number", toString(m[mkSymbol(c)]));
 }
 
 TEST_CASE("one_map_has_overlap_at_end_whereas_other_has_it_in_start")
 {
-    ScopedFastFlag sff{"LuauLValueAsKey", true};
-
     std::string a = "a";
     std::string b = "b";
     std::string c = "c";
@@ -125,18 +119,18 @@ TEST_CASE("one_map_has_overlap_at_end_whereas_other_has_it_in_start")
     TypeArena arena;
     merge(arena, m, other);
 
-    REQUIRE_EQ(5, m.NEW_refinements.size());
+    REQUIRE_EQ(5, m.size());
-    REQUIRE(m.NEW_refinements.count(mkSymbol(a)));
+    REQUIRE(m.count(mkSymbol(a)));
-    REQUIRE(m.NEW_refinements.count(mkSymbol(b)));
+    REQUIRE(m.count(mkSymbol(b)));
-    REQUIRE(m.NEW_refinements.count(mkSymbol(c)));
+    REQUIRE(m.count(mkSymbol(c)));
-    REQUIRE(m.NEW_refinements.count(mkSymbol(d)));
+    REQUIRE(m.count(mkSymbol(d)));
-    REQUIRE(m.NEW_refinements.count(mkSymbol(e)));
+    REQUIRE(m.count(mkSymbol(e)));
 
-    CHECK_EQ("string", toString(m.NEW_refinements[mkSymbol(a)]));
+    CHECK_EQ("string", toString(m[mkSymbol(a)]));
-    CHECK_EQ("number", toString(m.NEW_refinements[mkSymbol(b)]));
+    CHECK_EQ("number", toString(m[mkSymbol(b)]));
-    CHECK_EQ("boolean | string", toString(m.NEW_refinements[mkSymbol(c)]));
+    CHECK_EQ("boolean | string", toString(m[mkSymbol(c)]));
-    CHECK_EQ("number", toString(m.NEW_refinements[mkSymbol(d)]));
+    CHECK_EQ("number", toString(m[mkSymbol(d)]));
-    CHECK_EQ("boolean", toString(m.NEW_refinements[mkSymbol(e)]));
+    CHECK_EQ("boolean", toString(m[mkSymbol(e)]));
 }
 
 TEST_CASE("hashing_lvalue_global_prop_access")
@@ -159,7 +153,7 @@ TEST_CASE("hashing_lvalue_global_prop_access")
     CHECK_EQ(LValueHasher{}(t_x1), LValueHasher{}(t_x2));
     CHECK_EQ(LValueHasher{}(t_x2), LValueHasher{}(t_x2));
 
-    NEW_RefinementMap m;
+    RefinementMap m;
     m[t_x1] = getSingletonTypes().stringType;
     m[t_x2] = getSingletonTypes().numberType;
 
@@ -188,7 +182,7 @@ TEST_CASE("hashing_lvalue_local_prop_access")
     CHECK_NE(LValueHasher{}(t_x1), LValueHasher{}(t_x2));
     CHECK_EQ(LValueHasher{}(t_x2), LValueHasher{}(t_x2));
 
-    NEW_RefinementMap m;
+    RefinementMap m;
     m[t_x1] = getSingletonTypes().stringType;
     m[t_x2] = getSingletonTypes().numberType;
 

tests/Linter.test.cpp

@@ -54,6 +54,17 @@ return _
     CHECK_EQ(result.warnings[0].text, "Placeholder value '_' is read here; consider using a named variable");
 }
 
+TEST_CASE_FIXTURE(Fixture, "PlaceholderReadGlobal")
+{
+    LintResult result = lint(R"(
+_ = 5
+print(_)
+)");
+
+    CHECK_EQ(result.warnings.size(), 1);
+    CHECK_EQ(result.warnings[0].text, "Placeholder value '_' is read here; consider using a named variable");
+}
+
 TEST_CASE_FIXTURE(Fixture, "PlaceholderWrite")
 {
     LintResult result = lint(R"(
@@ -853,7 +864,7 @@ string.format("%Y")
 local _ = ("%"):format()
 
 -- correct format strings, just to uh make sure
-string.format("hello %d %f", 4, 5)
+string.format("hello %+10d %.02f %%", 4, 5)
 )");
 
     CHECK_EQ(result.warnings.size(), 4);
@@ -1078,16 +1089,18 @@ TEST_CASE_FIXTURE(Fixture, "FormatStringDate")
 os.date("%")
 os.date("%L")
 os.date("%?")
+os.date("\0")
 
 -- correct formats
 os.date("it's %c now")
 os.date("!*t")
 )");
 
-    CHECK_EQ(result.warnings.size(), 3);
+    CHECK_EQ(result.warnings.size(), 4);
     CHECK_EQ(result.warnings[0].text, "Invalid date format: unfinished replacement");
     CHECK_EQ(result.warnings[1].text, "Invalid date format: unexpected replacement character; must be a date format specifier or %");
     CHECK_EQ(result.warnings[2].text, "Invalid date format: unexpected replacement character; must be a date format specifier or %");
+    CHECK_EQ(result.warnings[3].text, "Invalid date format: date format can not contain null characters");
 }
 
 TEST_CASE_FIXTURE(Fixture, "FormatStringTyped")
@@ -1396,8 +1409,6 @@ end
 
 TEST_CASE_FIXTURE(Fixture, "TableOperations")
 {
-    ScopedFastFlag sff("LuauLintTableCreateTable", true);
-
     LintResult result = lintTyped(R"(
 local t = {}
 local tt = {}
@@ -1435,8 +1446,10 @@ table.create(42, {} :: {})
         "table.insert may change behavior if the call returns more than one result; consider adding parentheses around second argument");
     CHECK_EQ(result.warnings[6].text, "table.move uses index 0 but arrays are 1-based; did you mean 1 instead?");
     CHECK_EQ(result.warnings[7].text, "table.move uses index 0 but arrays are 1-based; did you mean 1 instead?");
-    CHECK_EQ(result.warnings[8].text, "table.create with a table literal will reuse the same object for all elements; consider using a for loop instead");
+    CHECK_EQ(
-    CHECK_EQ(result.warnings[9].text, "table.create with a table literal will reuse the same object for all elements; consider using a for loop instead");
+        result.warnings[8].text, "table.create with a table literal will reuse the same object for all elements; consider using a for loop instead");
+    CHECK_EQ(
+        result.warnings[9].text, "table.create with a table literal will reuse the same object for all elements; consider using a for loop instead");
 }
 
 TEST_CASE_FIXTURE(Fixture, "DuplicateConditions")

tests/Parser.test.cpp

@@ -7,8 +7,6 @@
 
 #include "doctest.h"
 
-LUAU_FASTFLAG(LuauFixAmbiguousErrorRecoveryInAssign)
-
 using namespace Luau;
 
 namespace
@@ -1639,10 +1637,7 @@ TEST_CASE_FIXTURE(Fixture, "parse_error_confusing_function_call")
         "Ambiguous syntax: this looks like an argument list for a function call, but could also be a start of new statement; use ';' to separate "
         "statements");
 
-    if (FFlag::LuauFixAmbiguousErrorRecoveryInAssign)
     CHECK(result4.errors.size() == 1);
-    else
-        CHECK(result4.errors.size() == 5);
 }
 
 TEST_CASE_FIXTURE(Fixture, "parse_error_varargs")

tests/TypeInfer.annotations.test.cpp

@@ -209,8 +209,6 @@ TEST_CASE_FIXTURE(Fixture, "as_expr_does_not_propagate_type_info")
 
 TEST_CASE_FIXTURE(Fixture, "as_expr_is_bidirectional")
 {
-    ScopedFastFlag sff{"LuauBidirectionalAsExpr", true};
-
     CheckResult result = check(R"(
         local a = 55 :: number?
         local b = a :: number
@@ -224,7 +222,6 @@ TEST_CASE_FIXTURE(Fixture, "as_expr_is_bidirectional")
 
 TEST_CASE_FIXTURE(Fixture, "as_expr_warns_on_unrelated_cast")
 {
-    ScopedFastFlag sff{"LuauBidirectionalAsExpr", true};
     ScopedFastFlag sff2{"LuauErrorRecoveryType", true};
 
     CheckResult result = check(R"(

tests/TypeInfer.builtins.test.cpp

@@ -889,4 +889,55 @@ TEST_CASE_FIXTURE(Fixture, "dont_add_definitions_to_persistent_types")
     REQUIRE(gtv->definition);
 }
 
+TEST_CASE_FIXTURE(Fixture, "assert_removes_falsy_types")
+{
+    ScopedFastFlag sff[]{
+        {"LuauAssertStripsFalsyTypes", true},
+        {"LuauDiscriminableUnions", true},
+    };
+
+    CheckResult result = check(R"(
+        local function f(x: (number | boolean)?)
+            return assert(x)
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+    CHECK_EQ("((boolean | number)?) -> number | true", toString(requireType("f")));
+}
+
+TEST_CASE_FIXTURE(Fixture, "assert_removes_falsy_types_even_from_type_pack_tail_but_only_for_the_first_type")
+{
+    ScopedFastFlag sff[]{
+        {"LuauAssertStripsFalsyTypes", true},
+        {"LuauDiscriminableUnions", true},
+    };
+
+    CheckResult result = check(R"(
+        local function f(...: number?)
+            return assert(...)
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+    CHECK_EQ("(...number?) -> (number, ...number?)", toString(requireType("f")));
+}
+
+TEST_CASE_FIXTURE(Fixture, "assert_returns_false_and_string_iff_it_knows_the_first_argument_cannot_be_truthy")
+{
+    ScopedFastFlag sff[]{
+        {"LuauAssertStripsFalsyTypes", true},
+        {"LuauDiscriminableUnions", true},
+    };
+
+    CheckResult result = check(R"(
+        local function f(x: nil)
+            return assert(x, "hmm")
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+    CHECK_EQ("(nil) -> nil", toString(requireType("f")));
+}
+
 TEST_SUITE_END();

tests/TypeInfer.provisional.test.cpp

@@ -176,19 +176,6 @@ TEST_CASE_FIXTURE(Fixture, "pass_a_union_of_tables_to_a_function_that_requires_a
     REQUIRE_EQ("{| [any]: any, x: number, y: number |}", toString(requireType("b")));
 }
 
-TEST_CASE_FIXTURE(Fixture, "normal_conditional_expression_has_refinements")
-{
-    CheckResult result = check(R"(
-        local foo: {x: number}? = nil
-        local bar = foo and foo.x -- TODO: Geez. We are inferring the wrong types here. Should be 'number?'.
-    )");
-
-    LUAU_REQUIRE_NO_ERRORS(result);
-
-    // Binary and/or return types are straight up wrong. JIRA: CLI-40300
-    CHECK_EQ("boolean | number", toString(requireType("bar")));
-}
-
 // Luau currently doesn't yet know how to allow assignments when the binding was refined.
 TEST_CASE_FIXTURE(Fixture, "while_body_are_also_refined")
 {

tests/TypeInfer.refinements.test.cpp

@@ -939,8 +939,6 @@ TEST_CASE_FIXTURE(Fixture, "type_comparison_ifelse_expression")
 
 TEST_CASE_FIXTURE(Fixture, "correctly_lookup_a_shadowed_local_that_which_was_previously_refined")
 {
-    ScopedFastFlag sff{"LuauLValueAsKey", true};
-
     CheckResult result = check(R"(
         local foo: string? = "hi"
         assert(foo)
@@ -955,8 +953,6 @@ TEST_CASE_FIXTURE(Fixture, "correctly_lookup_a_shadowed_local_that_which_was_pre
 
 TEST_CASE_FIXTURE(Fixture, "correctly_lookup_property_whose_base_was_previously_refined")
 {
-    ScopedFastFlag sff{"LuauLValueAsKey", true};
-
     CheckResult result = check(R"(
         type T = {x: string | number}
         local t: T? = {x = "hi"}
@@ -974,8 +970,6 @@ TEST_CASE_FIXTURE(Fixture, "correctly_lookup_property_whose_base_was_previously_
 
 TEST_CASE_FIXTURE(Fixture, "correctly_lookup_property_whose_base_was_previously_refined2")
 {
-    ScopedFastFlag sff{"LuauLValueAsKey", true};
-
     CheckResult result = check(R"(
         type T = { x: { y: number }? }
 
@@ -993,8 +987,6 @@ TEST_CASE_FIXTURE(Fixture, "correctly_lookup_property_whose_base_was_previously_
 
 TEST_CASE_FIXTURE(Fixture, "apply_refinements_on_astexprindexexpr_whose_subscript_expr_is_constant_string")
 {
-    ScopedFastFlag sff{"LuauRefiLookupFromIndexExpr", true};
-
     CheckResult result = check(R"(
         type T = { [string]: { prop: number }? }
         local t: T = {}
@@ -1061,27 +1053,62 @@ TEST_CASE_FIXTURE(Fixture, "discriminate_tag")
     CHECK_EQ("Dog", toString(requireTypeAtPosition({9, 33})));
 }
 
-TEST_CASE_FIXTURE(Fixture, "apply_refinements_on_astexprindexexpr_whose_subscript_expr_is_constant_string")
+TEST_CASE_FIXTURE(Fixture, "and_or_peephole_refinement")
 {
-    ScopedFastFlag sff{"LuauRefiLookupFromIndexExpr", true};
-
     CheckResult result = check(R"(
-        type T = { [string]: { prop: number }? }
+        local function len(a: {any})
-        local t: T = {}
+            return a and #a or nil
-
-        if t["hello"] then
-            local foo = t["hello"].prop
         end
     )");
 
     LUAU_REQUIRE_NO_ERRORS(result);
 }
 
-TEST_CASE_FIXTURE(Fixture, "and_or_peephole_refinement")
+TEST_CASE_FIXTURE(Fixture, "narrow_boolean_to_true_or_false")
 {
+    ScopedFastFlag sff[]{
+        {"LuauParseSingletonTypes", true},
+        {"LuauSingletonTypes", true},
+        {"LuauDiscriminableUnions", true},
+        {"LuauAssertStripsFalsyTypes", true},
+    };
+
     CheckResult result = check(R"(
-        local function len(a: {any})
+        local function is_true(b: true) end
-            return a and #a or nil
+        local function is_false(b: false) end
+
+        local function f(x: boolean)
+            if x then
+                is_true(x)
+            else
+                is_false(x)
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+}
+
+TEST_CASE_FIXTURE(Fixture, "discriminate_on_properties_of_disjoint_tables_where_that_property_is_true_or_false")
+{
+    ScopedFastFlag sff[]{
+        {"LuauParseSingletonTypes", true},
+        {"LuauSingletonTypes", true},
+        {"LuauDiscriminableUnions", true},
+        {"LuauAssertStripsFalsyTypes", true},
+    };
+
+    CheckResult result = check(R"(
+        type Ok<T> = { ok: true, value: T }
+        type Err<E> = { ok: false, error: E }
+        type Result<T, E> = Ok<T> | Err<E>
+
+        local function apply<T, E>(t: Result<T, E>, f: (T) -> (), g: (E) -> ())
+            if t.ok then
+                f(t.value)
+            else
+                g(t.error)
+            end
         end
     )");
 

tests/TypeInfer.test.cpp

@@ -2429,21 +2429,6 @@ TEST_CASE_FIXTURE(Fixture, "should_be_able_to_infer_this_without_stack_overflowi
     LUAU_REQUIRE_NO_ERRORS(result);
 }
 
-TEST_CASE_FIXTURE(Fixture, "x_or_y_forces_both_x_and_y_to_be_of_same_type_if_either_is_free")
-{
-    CheckResult result = check(R"(
-        local function f(x, y) return x or y end
-
-        local x = f(1, 2)
-        local y = f(3, "foo")
-    )");
-
-    LUAU_REQUIRE_ERROR_COUNT(1, result);
-    CHECK_EQ(*requireType("x"), *typeChecker.numberType);
-
-    CHECK_EQ(result.errors[0], (TypeError{Location{{4, 23}, {4, 28}}, TypeMismatch{typeChecker.numberType, typeChecker.stringType}}));
-}
-
 TEST_CASE_FIXTURE(Fixture, "inferring_hundreds_of_self_calls_should_not_suffocate_memory")
 {
     CheckResult result = check(R"(
@@ -5012,16 +4997,14 @@ local b: B = a
     )");
 
     LUAU_REQUIRE_ERROR_COUNT(1, result);
-    CHECK_EQ(
+    CHECK_EQ(toString(result.errors[0]),
-        toString(result.errors[0]), R"(Type '(number, number) -> (number, string)' could not be converted into '(number, number) -> (number, boolean)'
+        R"(Type '(number, number) -> (number, string)' could not be converted into '(number, number) -> (number, boolean)'
 caused by:
   Return #2 type is not compatible. Type 'string' could not be converted into 'boolean')");
 }
 
 TEST_CASE_FIXTURE(Fixture, "prop_access_on_any_with_other_options")
 {
-    ScopedFastFlag sff{"LuauLValueAsKey", true};
-
     CheckResult result = check(R"(
         local function f(thing: any | string)
             local foo = thing.SomeRandomKey
@@ -5120,4 +5103,65 @@ end
     )");
 }
 
+TEST_CASE_FIXTURE(Fixture, "cli_50041_committing_txnlog_in_apollo_client_error")
+{
+    ScopedFastFlag committingTxnLog{"LuauUseCommittingTxnLog", true};
+    ScopedFastFlag subtypingVariance{"LuauTableSubtypingVariance2", true};
+
+    CheckResult result = check(R"(
+        --!strict
+        --!nolint
+
+        type FieldSpecifier = {
+            fieldName: string,
+        }
+
+        type ReadFieldOptions = FieldSpecifier & { from: number? }
+
+        type Policies = {
+            getStoreFieldName: (self: Policies, fieldSpec: FieldSpecifier) -> string,
+        }
+
+        local Policies = {}
+
+        local function foo(p: Policies)
+        end
+
+        function Policies:getStoreFieldName(specifier: FieldSpecifier): string
+            return ""
+        end
+
+        function Policies:readField(options: ReadFieldOptions)
+            local _ = self:getStoreFieldName(options)
+            --[[
+                Type error:
+                TypeError { "MainModule", Location { { line = 25, col = 16 }, { line = 25, col = 20 } }, TypeMismatch { Policies, {- getStoreFieldName: (tp1) -> (a, b...) -} } }
+            ]]
+            foo(self)
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+}
+
+TEST_CASE_FIXTURE(Fixture, "do_not_modify_imported_types")
+{
+    ScopedFastFlag noSealedTypeMod{"LuauNoSealedTypeMod", true};
+
+    fileResolver.source["game/A"] = R"(
+export type Type = { unrelated: boolean }
+return {}
+    )";
+
+    fileResolver.source["game/B"] = R"(
+local types = require(game.A)
+type Type = types.Type
+local x: Type = {}
+function x:Destroy(): () end
+    )";
+
+    CheckResult result = frontend.check("game/B");
+    LUAU_REQUIRE_ERRORS(result);
+}
+
 TEST_SUITE_END();

tests/TypeInfer.tryUnify.test.cpp

@@ -260,4 +260,17 @@ TEST_CASE_FIXTURE(TryUnifyFixture, "free_tail_is_grown_properly")
     CHECK(unifyErrors.size() == 0);
 }
 
+TEST_CASE_FIXTURE(TryUnifyFixture, "recursive_metatable_getmatchtag")
+{
+    ScopedFastFlag luauUnionTagMatchFix{"LuauUnionTagMatchFix", true};
+
+    TypeVar redirect{FreeTypeVar{TypeLevel{}}};
+    TypeVar table{TableTypeVar{}};
+    TypeVar metatable{MetatableTypeVar{&redirect, &table}};
+    redirect = BoundTypeVar{&metatable}; // Now we have a metatable that is recursive on the table type
+    TypeVar variant{UnionTypeVar{{&metatable, typeChecker.numberType}}};
+
+    state.tryUnify(&metatable, &variant);
+}
+
 TEST_SUITE_END();

tests/conformance/basic.lua

@@ -118,6 +118,10 @@ assert((function() return #_G end)() == 0)
 assert((function() return #{1,2} end)() == 2)
 assert((function() return #'g' end)() == 1)
 
+local ud = newproxy(true)
+getmetatable(ud).__len = function() return 42 end
+assert((function() return #ud end)() == 42)
+
 assert((function() local a = 1 a = -a return a end)() == -1)
 
 -- while/repeat

tests/conformance/vararg.lua

@@ -105,6 +105,45 @@ assert(a==5 and b==4 and c==3 and d==2 and e==1)
 a,b,c,d,e = f(4)
 assert(a==nil and b==nil and c==nil and d==nil and e==nil)
 
+-- select tests
+a = {select(3, unpack{10,20,30,40})}
+assert(table.getn(a) == 2 and a[1] == 30 and a[2] == 40)
+a = {select(1)}
+assert(next(a) == nil)
+a = {select(-1, 3, 5, 7)}
+assert(a[1] == 7 and a[2] == nil)
+a = {select(-2, 3, 5, 7)}
+assert(a[1] == 5 and a[2] == 7 and a[3] == nil)
+pcall(select, 10000)
+pcall(select, -10000)
+
+-- select(_, ...) has special optimizations so it needs extra testing
+function selectone(n, ...)
+    local e = select(n, ...)
+    return e
+end
+
+function selectmany(n, ...)
+    return table.concat({select(n, ...)}, ',')
+end
+
+assert(selectone('#') == 0)
+assert(selectmany('#') == "0")
+
+assert(selectone('#', 10, 20, 30) == 3)
+assert(selectmany('#', 10, 20, 30) == "3")
+
+assert(selectone(1, 10, 20, 30) == 10)
+assert(selectmany(1, 10, 20, 30) == "10,20,30")
+
+assert(selectone(2, 10, 20, 30) == 20)
+assert(selectmany(2, 10, 20, 30) == "20,30")
+
+assert(selectone(-2, 10, 20, 30) == 20)
+assert(selectmany(-2, 10, 20, 30) == "20,30")
+
+assert(selectone('3', 10, 20, 30) == 30)
+assert(selectmany('3', 10, 20, 30) == "30")
 
 -- varargs for main chunks
 f = loadstring[[ return {...} ]]
@@ -122,16 +161,5 @@ f = loadstring[[
 assert(f("a", "b", nil, {}, assert))
 assert(f())
 
-a = {select(3, unpack{10,20,30,40})}
-assert(table.getn(a) == 2 and a[1] == 30 and a[2] == 40)
-a = {select(1)}
-assert(next(a) == nil)
-a = {select(-1, 3, 5, 7)}
-assert(a[1] == 7 and a[2] == nil)
-a = {select(-2, 3, 5, 7)}
-assert(a[1] == 5 and a[2] == 7 and a[3] == nil)
-pcall(select, 10000)
-pcall(select, -10000)
-
 return('OK')