Generator objects can suspend

src/parser.cc

Index: src/parser.cc
diff --git a/src/parser.cc b/src/parser.cc
index b4ab623829b9657382ab58bcbe347ce4b31d3dff..8ec5b6a4a095c6c506ce2bc5bd43b24d9bf28376 100644
--- a/src/parser.cc
+++ b/src/parser.cc
@@ -2510,16 +2510,24 @@ Statement* Parser::ParseReturnStatement(bool* ok) {
 
   Token::Value tok = peek();
   Statement* result;
+  Expression* return_value;
   if (scanner().HasAnyLineTerminatorBeforeNext() ||
       tok == Token::SEMICOLON ||
       tok == Token::RBRACE ||
       tok == Token::EOS) {
-    ExpectSemicolon(CHECK_OK);
-    result = factory()->NewReturnStatement(GetLiteralUndefined());
+    return_value = GetLiteralUndefined();
   } else {
-    Expression* expr = ParseExpression(true, CHECK_OK);
-    ExpectSemicolon(CHECK_OK);
-    result = factory()->NewReturnStatement(expr);
+    return_value = ParseExpression(true, CHECK_OK);
+  }
+  ExpectSemicolon(CHECK_OK);
+  if (is_generator()) {
+    Expression* iterator = factory()->NewVariableProxy(

[Michael Starzinger, 2013/04/17 13:43:48]

Hehe, you really like calling generator objects "iterator". Could I convince you
to rename this local variable to "generator" instead?

+        current_function_state_->generator_object_variable());
+    Expression* yield = factory()->NewYield(
+        iterator, return_value, Yield::FINAL, RelocInfo::kNoPosition);
+    result = factory()->NewExpressionStatement(yield);

[Michael Starzinger, 2013/04/17 13:43:48]

Could we add parsing tests to generators-parsing.js that have a return
statements? I know we cannot test execution yet, but we should test generating
the AST for them. I was thinking along the lines of ...

function* g() { yield 1; return; }
function* g() { yield 1; return 2; }
function* g() { yield 1; return 2; yield "dead"; }

+  } else {
+    result = factory()->NewReturnStatement(return_value);
   }
 
   // An ECMAScript program is considered syntactically incorrect if it
@@ -3099,12 +3107,12 @@ Expression* Parser::ParseYieldExpression(bool* ok) {
   //   'yield' '*'? AssignmentExpression
   int position = scanner().peek_location().beg_pos;
   Expect(Token::YIELD, CHECK_OK);
-  bool is_yield_star = Check(Token::MUL);
+  Yield::Kind kind =
+      Check(Token::MUL) ? Yield::DELEGATING : Yield::SUSPEND;
   Expression* generator_object = factory()->NewVariableProxy(
       current_function_state_->generator_object_variable());
   Expression* expression = ParseAssignmentExpression(false, CHECK_OK);
-  return factory()->NewYield(generator_object, expression, is_yield_star,
-                             position);
+  return factory()->NewYield(generator_object, expression, kind, position);
 }
 
 
@@ -4580,7 +4588,7 @@ FunctionLiteral* Parser::ParseFunctionLiteral(Handle<String> function_name,
         VariableProxy* get_proxy = factory()->NewVariableProxy(
             current_function_state_->generator_object_variable());
         Yield* yield = factory()->NewYield(
-            get_proxy, assignment, false, RelocInfo::kNoPosition);
+            get_proxy, assignment, Yield::INITIAL, RelocInfo::kNoPosition);
         body->Add(factory()->NewExpressionStatement(yield), zone());
       }