From 7a745faacf5fb494364df32a8de2c512cfec71ef Mon Sep 17 00:00:00 2001
From: TopchetoEU <36534413+TopchetoEU@users.noreply.github.com>
Date: Sat, 26 Aug 2023 00:41:28 +0300
Subject: [PATCH] feat: implement async generators

---
 lib/values/function.ts                        | 51 +++++++++++++++++--
 .../topchetoeu/jscript/parsing/Parsing.java   | 18 ++++---
 2 files changed, 58 insertions(+), 11 deletions(-)

diff --git a/lib/values/function.ts b/lib/values/function.ts
index 577c95d..52bbf43 100644
--- a/lib/values/function.ts
+++ b/lib/values/function.ts
@@ -20,7 +20,7 @@ interface FunctionConstructor extends Function {
     asyncGenerator<ArgsT extends any[], RetT>(
         func: (await: <T>(val: T) => Awaited<T>, _yield: <T>(val: T) => void) => (...args: ArgsT) => RetT
     ): (...args: ArgsT) => AsyncGenerator<RetT>;
-    generator<ArgsT extends any[], T, RetT, TNext>(
+    generator<ArgsT extends any[], T = unknown, RetT = unknown, TNext = unknown>(
         func: (_yield: <T>(val: T) => TNext) => (...args: ArgsT) => RetT
     ): (...args: ArgsT) => Generator<T, RetT, TNext>;
 }
@@ -90,7 +90,7 @@ setProps(Function.prototype, {
     },
 });
 setProps(Function, {
-    async<ArgsT extends any[], RetT>(func: (_yield: <T>(val: T) => Awaited<T>) => (...args: ArgsT) => RetT) {
+    async(func) {
         if (typeof func !== 'function') throw new TypeError('Expected func to be function.');
 
         return function (this: any) {
@@ -121,8 +121,53 @@ setProps(Function, {
             });
         };
     },
+    asyncGenerator(func) {
+        if (typeof func !== 'function') throw new TypeError('Expected func to be function.');
+
+
+        return function(this: any) {
+            const gen = Function.generator<any[], ['await' | 'yield', any]>((_yield) => func(
+                val => _yield(['await', val]) as any,
+                val => _yield(['yield', val])
+            )).apply(this, arguments as any);
+
+            const next = (resolve: Function, reject: Function, type: 'none' | 'val' | 'ret' | 'err', val?: any) => {
+                let res;
+
+                try {
+                    switch (type) {
+                        case 'val': res = gen.next(val); break;
+                        case 'ret': res = gen.return(val); break;
+                        case 'err': res = gen.throw(val); break;
+                        default: res = gen.next(); break;
+                    }
+                }
+                catch (e) { return reject(e); }
+
+                if (res.done) return { done: true, res: <any>res };
+                else if (res.value[0] === 'await') Promise.resolve(res.value[1]).then(
+                    v => next(resolve, reject, 'val', v),
+                    v => next(resolve, reject, 'err', v),
+                )
+                else resolve({ done: false, value: res.value[1] });
+            };
+
+            return {
+                next() {
+                    const args = arguments;
+                    if (arguments.length === 0) return new Promise((res, rej) => next(res, rej, 'none'));
+                    else return new Promise((res, rej) => next(res, rej, 'val', args[0]));
+                },
+                return: (value) => new Promise((res, rej) => next(res, rej, 'ret', value)),
+                throw: (value) => new Promise((res, rej) => next(res, rej, 'err', value)),
+                [Symbol.asyncIterator]() { return this; }
+            }
+        }
+    },
     generator(func) {
         if (typeof func !== 'function') throw new TypeError('Expected func to be function.');
-        return internals.makeGenerator(func);
+        return Object.assign(internals.makeGenerator(func), {
+            [Symbol.iterator]() { return this; }
+        });
     }
 })
\ No newline at end of file
diff --git a/src/me/topchetoeu/jscript/parsing/Parsing.java b/src/me/topchetoeu/jscript/parsing/Parsing.java
index 6c816dc..dde815b 100644
--- a/src/me/topchetoeu/jscript/parsing/Parsing.java
+++ b/src/me/topchetoeu/jscript/parsing/Parsing.java
@@ -981,7 +981,14 @@ public class Parsing {
     }
     @SuppressWarnings("all")
     public static ParseRes<? extends Statement> parseSimple(String filename, List<Token> tokens, int i, boolean statement) {
-        var res = new ArrayList<>(List.of(
+        var res = new ArrayList<>();
+
+        if (!statement) {
+            res.add(parseObject(filename, tokens, i));
+            res.add(parseFunction(filename, tokens, i, false));
+        }
+
+        res.addAll(List.of(
             parseVariable(filename, tokens, i),
             parseLiteral(filename, tokens, i),
             parseString(filename, tokens, i),
@@ -997,11 +1004,6 @@ public class Parsing {
             parseDelete(filename, tokens, i)
         ));
 
-        if (!statement) {
-            res.add(parseObject(filename, tokens, i));
-            res.add(parseFunction(filename, tokens, i, false));
-        }
-
         return ParseRes.any(res.toArray(ParseRes[]::new));
     }
 
@@ -1795,7 +1797,6 @@ public class Parsing {
             parseContinue(filename, tokens, i),
             parseBreak(filename, tokens, i),
             parseDebug(filename, tokens, i),
-            parseValueStatement(filename, tokens, i),
             parseIf(filename, tokens, i),
             parseWhile(filename, tokens, i),
             parseSwitch(filename, tokens, i),
@@ -1804,7 +1805,8 @@ public class Parsing {
             parseDoWhile(filename, tokens, i),
             parseCatch(filename, tokens, i),
             parseCompound(filename, tokens, i),
-            parseFunction(filename, tokens, i, true)
+            parseFunction(filename, tokens, i, true),
+            parseValueStatement(filename, tokens, i)
         );
     }