From 6f02130e516bd3e14ba23f0ce3c12c406c848cb0 Mon Sep 17 00:00:00 2001
From: Erica Marigold <hi@devcomp.xyz>
Date: Sun, 14 Apr 2024 19:19:08 +0530
Subject: [PATCH] chore(Future): include await system and fallible futures

---
 lib/future.luau | 46 ++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 38 insertions(+), 8 deletions(-)

diff --git a/lib/future.luau b/lib/future.luau
index 766c4f4..d7bd8b1 100644
--- a/lib/future.luau
+++ b/lib/future.luau
@@ -4,6 +4,12 @@ local mod = require("../mod")
 local Signal = mod.signal
 type Signal<T...> = mod.Signal<T...>
 
+local result = require("result")
+local Result = result.Result
+export type Result<T, E> = result.Result<T, E>
+local Ok = result.Ok
+local Err = result.Err
+
 local Future = {}
 export type Status = "initialized" | "running" | "cancelled" | "done"
 export type Future<T> = typeof(Future) & {
@@ -11,19 +17,14 @@ export type Future<T> = typeof(Future) & {
 	_ret: T,
 	_thread: thread,
 	_spawnEvt: Signal<()>,
-	_retEvt: Signal<T, Status>,
+	_retEvt: Signal<T | Result<T, string>, Status>,
 	_status: Status,
 }
 
-function Future.new<T>(fn: (...any) -> T, args: { any })
+local function _constructor<T>(fn: (Signal<()>, Signal<T, Status>) -> (), args: { any })
 	return setmetatable(
 		{
-			_thread = coroutine.create(function(spawnEvt: Signal<()>, retEvt: Signal<T, Status>)
-				spawnEvt:Fire()
-
-				local ret = fn(table.unpack(args))
-				retEvt:Fire(ret, "done")
-			end),
+			_thread = coroutine.create(fn),
 
 			_spawnEvt = Signal.new(),
 			_retEvt = Signal.new(),
@@ -35,6 +36,25 @@ function Future.new<T>(fn: (...any) -> T, args: { any })
 	)
 end
 
+function Future.new<T>(fn: (...any) -> T, args: { any })
+	return _constructor(function(spawnEvt: Signal<()>, retEvt: Signal<T, Status>)
+		spawnEvt:Fire()
+
+		local ret = fn(table.unpack(args))
+		retEvt:Fire(ret, "done")
+	end, args)
+end
+
+function Future.try<T>(fn: (...any) -> T, args: { any })
+	return _constructor(function(spawnEvt: Signal<()>, retEvt: Signal<Result<T, string>, Status>)
+		spawnEvt:Fire()
+
+		local ok, ret = pcall(fn, table.unpack(args))
+		local result: Result<T, string> = if ok then Ok(ret) else Err(ret)
+		retEvt:Fire(result, "done")
+	end, args)
+end
+
 function Future.poll<T>(self: Future<T>): (Status, T)
 	if self._status == "initialized" then
 		self._retEvt:Connect(function(firedRet, status: Status)
@@ -68,3 +88,13 @@ function Future.cancel<T>(self: Future<T>)
 	self._retEvt:Fire(nil :: any, "cancelled")
 	self._status = "cancelled"
 end
+
+function Future.await<T>(self: Future<T>): T
+	while true do
+		local status: Status, ret: T = self:poll()
+
+		if status == "done" then
+			return ret
+		end
+	end
+end