Initial scaffolding to get custom globals and require working

src/cli/repl.rs

@@ -32,7 +32,7 @@ pub async fn show_interface() -> Result<ExitCode> {
     let mut prompt_state = PromptState::Regular;
     let mut source_code = String::new();
 
-    let lune_instance = Lune::new();
+    let mut lune_instance = Lune::new();
 
     loop {
         let prompt = match prompt_state {

src/lune/globals/mod.rs

@@ -0,0 +1,18 @@
+use mlua::prelude::*;
+
+use super::util::TableBuilder;
+
+mod require;
+
+pub fn inject_all(lua: &'static Lua) -> LuaResult<()> {
+    let all = TableBuilder::new(lua)?
+        .with_value("require", require::create(lua)?)?
+        .build_readonly()?;
+
+    for res in all.pairs() {
+        let (key, value): (LuaValue, LuaValue) = res?;
+        lua.globals().set(key, value)?;
+    }
+
+    Ok(())
+}

src/lune/globals/require/absolute.rs

@@ -0,0 +1,13 @@
+use mlua::prelude::*;
+
+use super::context::*;
+
+pub(super) async fn require<'lua>(
+    _lua: &'lua Lua,
+    _ctx: RequireContext,
+    path: &str,
+) -> LuaResult<LuaValue<'lua>> {
+    Err(LuaError::runtime(format!(
+        "TODO: Support require for absolute paths (tried to require '{path}')"
+    )))
+}

src/lune/globals/require/alias.rs

@@ -0,0 +1,14 @@
+use mlua::prelude::*;
+
+use super::context::*;
+
+pub(super) async fn require<'lua>(
+    _lua: &'lua Lua,
+    _ctx: RequireContext,
+    alias: &str,
+    name: &str,
+) -> LuaResult<LuaValue<'lua>> {
+    Err(LuaError::runtime(format!(
+        "TODO: Support require for built-in libraries (tried to require '{name}' with alias '{alias}')"
+    )))
+}

src/lune/globals/require/builtin.rs

@@ -0,0 +1,13 @@
+use mlua::prelude::*;
+
+use super::context::*;
+
+pub(super) async fn require<'lua>(
+    _lua: &'lua Lua,
+    _ctx: RequireContext,
+    name: &str,
+) -> LuaResult<LuaValue<'lua>> {
+    Err(LuaError::runtime(format!(
+        "TODO: Support require for built-in libraries (tried to require '{name}')"
+    )))
+}

src/lune/globals/require/context.rs

@@ -0,0 +1,43 @@
+use mlua::prelude::*;
+
+const REGISTRY_KEY: &str = "RequireContext";
+
+// TODO: Store current file path for each thread in
+// this context somehow, as well as built-in libraries
+#[derive(Clone)]
+pub(super) struct RequireContext {
+    pub(super) use_absolute_paths: bool,
+}
+
+impl RequireContext {
+    pub fn new() -> Self {
+        Self {
+            // TODO: Set to false by default, load some kind of config
+            // or env var to check if we should be using absolute paths
+            use_absolute_paths: true,
+        }
+    }
+
+    pub fn from_registry(lua: &Lua) -> Self {
+        lua.named_registry_value(REGISTRY_KEY)
+            .expect("Missing require context in lua registry")
+    }
+
+    pub fn insert_into_registry(self, lua: &Lua) {
+        lua.set_named_registry_value(REGISTRY_KEY, self)
+            .expect("Failed to insert RequireContext into registry");
+    }
+}
+
+impl LuaUserData for RequireContext {}
+
+impl<'lua> FromLua<'lua> for RequireContext {
+    fn from_lua(value: LuaValue<'lua>, _: &'lua Lua) -> LuaResult<Self> {
+        if let LuaValue::UserData(ud) = value {
+            if let Ok(ctx) = ud.borrow::<RequireContext>() {
+                return Ok(ctx.clone());
+            }
+        }
+        unreachable!("RequireContext should only be used from registry")
+    }
+}

src/lune/globals/require/mod.rs

@@ -0,0 +1,41 @@
+use mlua::prelude::*;
+
+use crate::lune::scheduler::LuaSchedulerExt;
+
+mod context;
+use context::RequireContext;
+
+mod absolute;
+mod alias;
+mod builtin;
+mod relative;
+
+pub fn create(lua: &'static Lua) -> LuaResult<impl IntoLua<'_>> {
+    RequireContext::new().insert_into_registry(lua);
+
+    lua.create_async_function(|lua, path: LuaString| async move {
+        let context = RequireContext::from_registry(lua);
+
+        let path = path
+            .to_str()
+            .into_lua_err()
+            .context("Failed to parse require path as string")?
+            .to_string();
+
+        if let Some(builtin_name) = path
+            .strip_prefix("@lune/")
+            .map(|name| name.to_ascii_lowercase())
+        {
+            builtin::require(lua, context, &builtin_name).await
+        } else if let Some(aliased_path) = path.strip_prefix('@') {
+            let (alias, name) = aliased_path.split_once('/').ok_or(LuaError::runtime(
+                "Require with custom alias must contain '/' delimiter",
+            ))?;
+            alias::require(lua, context, alias, name).await
+        } else if context.use_absolute_paths {
+            absolute::require(lua, context, &path).await
+        } else {
+            relative::require(lua, context, &path).await
+        }
+    })
+}

src/lune/globals/require/relative.rs

@@ -0,0 +1,13 @@
+use mlua::prelude::*;
+
+use super::context::*;
+
+pub(super) async fn require<'lua>(
+    _lua: &'lua Lua,
+    _ctx: RequireContext,
+    path: &str,
+) -> LuaResult<LuaValue<'lua>> {
+    Err(LuaError::runtime(format!(
+        "TODO: Support require for absolute paths (tried to require '{path}')"
+    )))
+}

src/lune/mod.rs

@@ -1,6 +1,7 @@
 use std::process::ExitCode;
 
 mod error;
+mod globals;
 mod scheduler;
 mod util;
 
@@ -12,6 +13,7 @@ use mlua::Lua;
 #[derive(Debug, Clone)]
 pub struct Lune {
     lua: &'static Lua,
+    scheduler: &'static Scheduler<'static, 'static>,
     args: Vec<String>,
 }
 
@@ -21,8 +23,19 @@ impl Lune {
     */
     #[allow(clippy::new_without_default)]
     pub fn new() -> Self {
+        // FIXME: Leaking these and using a manual drop implementation
+        // does not feel great... is there any way for us to create a
+        // scheduler, store it in app data, and guarantee it has
+        // the same lifetime as Lua without using any unsafe?
+        let lua = Lua::new().into_static();
+        let scheduler = Scheduler::new(lua).into_static();
+
+        lua.set_app_data(scheduler);
+        globals::inject_all(lua).expect("Failed to inject lua globals");
+
         Self {
-            lua: Lua::new().into_static(),
+            lua,
+            scheduler,
             args: Vec::new(),
         }
     }
@@ -42,29 +55,29 @@ impl Lune {
         Runs a Lune script inside of a new Luau VM.
     */
     pub async fn run(
-        &self,
+        &mut self,
         script_name: impl AsRef<str>,
         script_contents: impl AsRef<[u8]>,
     ) -> Result<ExitCode, LuneError> {
-        let scheduler = Scheduler::new(self.lua);
-        self.lua.set_app_data(scheduler.clone());
-
         let main = self
             .lua
             .load(script_contents.as_ref())
             .set_name(script_name.as_ref());
 
-        scheduler.push_back(main, ())?;
+        self.scheduler.push_back(main, ())?;
-        Ok(scheduler.run_to_completion().await)
+        Ok(self.scheduler.run_to_completion().await)
     }
 }
 
 impl Drop for Lune {
     fn drop(&mut self) {
-        // SAFETY: The scheduler needs the static lifetime reference to lua,
+        // SAFETY: When the Lune struct is dropped, it is guaranteed
-        // when dropped nothing outside of here has access to the scheduler
+        // that the Lua and Scheduler structs are no longer being used,
+        // since all the methods that reference them (eg. `run`)
+        // take an exclusive / mutable reference
         unsafe {
             Lua::from_static(self.lua);
+            Scheduler::from_static(self.scheduler);
         }
     }
 }

src/lune/scheduler/impl_async.rs

@@ -23,6 +23,8 @@ where
 
     /**
         Schedules the given `thread` to run when the given `fut` completes.
+
+        If the given future returns a [`LuaError`], that error will be passed to the given `thread`.
     */
     pub fn schedule_future_thread<F, FR>(
         &'fut self,
@@ -35,6 +37,7 @@ where
     {
         let thread = thread.into_owned_lua_thread(self.lua)?;
         self.schedule_future(async move {
+            // TODO: Throw any error back to lua instead of panicking here
             let rets = fut.await.expect("Failed to receive result");
             let rets = rets
                 .into_lua_multi(self.lua)

src/lune/scheduler/mod.rs

@@ -51,4 +51,14 @@ impl<'lua, 'fut> Scheduler<'lua, 'fut> {
             futures: Arc::new(AsyncMutex::new(FuturesUnordered::new())),
         }
     }
+
+    #[doc(hidden)]
+    pub fn into_static(self) -> &'static Self {
+        Box::leak(Box::new(self))
+    }
+
+    #[doc(hidden)]
+    pub unsafe fn from_static(lua: &'static Scheduler) -> Self {
+        *Box::from_raw(lua as *const Scheduler as *mut Scheduler)
+    }
 }

src/lune/scheduler/traits.rs

@@ -65,6 +65,7 @@ where
         let async_func = self
             .load(ASYNC_IMPL_LUA)
             .set_name("async")
+            .set_environment(async_env)
             .into_function()?;
         Ok(async_func)
     }

src/tests.rs

@@ -20,7 +20,7 @@ macro_rules! create_tests {
             // The rest of the test logic can continue as normal
             let full_name = format!("tests/{}.luau", $value);
             let script = read_to_string(&full_name).await?;
-            let lune = Lune::new().with_args(
+            let mut lune = Lune::new().with_args(
                 ARGS
                     .clone()
                     .iter()