feat: add generator expression support fixes #449

src/compiler/compiler.c

@@ -1766,7 +1766,28 @@ static Error* exprGroup(Compiler* self) {
         Ctx__s_push(ctx(), (Expr*)TupleExpr__new(line, 0));
         return NULL;
     }
-    check(EXPR_TUPLE(self));  // () is just for change precedence
+    check(EXPR(self));  // parse first expression
+    // check for generator expression
+    if(match(TK_FOR)) {
+        check(consume_comp(self, OP_BUILD_LIST, OP_LIST_APPEND));
+        consume(TK_RPAREN);
+        return NULL;
+    }
+    // not a generator, continue with tuple/grouped expression logic
+    if(match(TK_COMMA)) {
+        // tuple expression
+        int count = 1;
+        do {
+            if(curr()->type == TK_RPAREN) break;
+            check(EXPR(self));
+            count += 1;
+        } while(match(TK_COMMA));
+        SequenceExpr* e = TupleExpr__new(line, count);
+        for(int i = count - 1; i >= 0; i--) {
+            e->items[i] = Ctx__s_popx(ctx());
+        }
+        Ctx__s_push(ctx(), (Expr*)e);
+    }
     consume(TK_RPAREN);
     if(Ctx__s_top(ctx())->vt->is_tuple) return NULL;
     GroupedExpr* g = GroupedExpr__new(line, Ctx__s_popx(ctx()));

tests/510_yield.py

@@ -127,4 +127,16 @@ def f():
     a = yield from g()
     yield a
 
-assert list(f()) == [1, 2, 3]
+assert list(f()) == [1, 2, 3]
+
+
+# Generator expressions
+squares = (x**2 for x in range(5))
+assert list(squares) == [0, 1, 4, 9, 16]
+
+evens = (x for x in range(10) if x % 2 == 0)
+assert list(evens) == [0, 2, 4, 6, 8]
+
+# Generator expression with nested iteration
+pairs = ((i, j) for i in range(3) for j in range(2))
+assert list(pairs) == [(0, 0), (0, 1), (1, 0), (1, 1), (2, 0), (2, 1)]