Implement handling of arrow functions in the parser

src/parser.cc

Index: src/parser.cc
diff --git a/src/parser.cc b/src/parser.cc
index 42d094938657541fa00a4ae2d14fe31a43e9e456..ec9435b0bd0d87276920beb35e536465600ece84 100644
--- a/src/parser.cc
+++ b/src/parser.cc
@@ -678,8 +678,9 @@ const AstString* ParserTraits::GetNextSymbol(Scanner* scanner) {
 
 Expression* ParserTraits::ThisExpression(
     Scope* scope,
-    AstNodeFactory<AstConstructionVisitor>* factory) {
-  return factory->NewVariableProxy(scope->receiver());
+    AstNodeFactory<AstConstructionVisitor>* factory,
+    int pos) {
+  return factory->NewVariableProxy(scope->receiver(), pos);
 }
 
 
@@ -784,6 +785,7 @@ Parser::Parser(CompilationInfo* info)
   set_allow_lazy(false);  // Must be explicitly enabled.
   set_allow_generators(FLAG_harmony_generators);
   set_allow_for_of(FLAG_harmony_iteration);
+  set_allow_arrow_functions(FLAG_harmony_arrow_functions);
   set_allow_harmony_numeric_literals(FLAG_harmony_numeric_literals);
 }
 
@@ -3302,6 +3304,66 @@ Handle<FixedArray> CompileTimeValue::GetElements(Handle<FixedArray> value) {
 }
 
 
+Vector<VariableProxy*> ParserTraits::ParameterListFromExpression(
+    Expression* expression, bool* ok) {
+
+  // Parsing the parameter list of an arrow function does not have parameters
+  // (as in: () => ...) returns NULL, so expression being NULL is not an error,
+  // but an valid empty parameter list.
+  if (expression == NULL)
+    return Vector<VariableProxy*>::empty();
+
+  const char* error_token = NULL;
+  Collector<VariableProxy*> collector;
+
+  while (expression->IsBinaryOperation()) {
+    BinaryOperation* binop = expression->AsBinaryOperation();
+
+    if (binop->op() != Token::COMMA) {
+      error_token = Token::String(expression->AsBinaryOperation()->op());
+      break;
+    }
+
+    expression = binop->right();
+    if (!expression->IsVariableProxy()) {
+      error_token = "";
+      break;
+    }
+    if (expression->AsVariableProxy()->is_this()) {
+      error_token = Token::String(Token::THIS);
+      break;
+    }
+
+    collector.Add(expression->AsVariableProxy());
+    expression = binop->left();
+  }
+
+  // No errors were found in the loop above, try to add the remaining item.
+  if (error_token == NULL) {
+    if (!expression->IsVariableProxy()) {
+      error_token = "";
+    } else if (expression->AsVariableProxy()->is_this()) {
+      error_token = Token::String(Token::THIS);
+    } else {
+      collector.Add(expression->AsVariableProxy());
+      return collector.ToVector();
+    }
+  }
+
+  // Report errors.
+  ASSERT_NE(error_token, NULL);
+  int error_pos = expression->position();
+  int error_token_len = strlen(error_token);
+  ParserTraits::ReportMessageAt(
+      Scanner::Location(error_pos,
+                        error_pos + error_token_len ? error_token_len : 1),
+      "unexpected_token",
+      error_token);
+  *ok = false;
+  return Vector<VariableProxy*>::empty();
+}
+
+
 FunctionLiteral* Parser::ParseFunctionLiteral(
     const AstString* function_name,
     Scanner::Location function_name_location,
@@ -3522,34 +3584,15 @@ FunctionLiteral* Parser::ParseFunctionLiteral(
       handler_count = function_state.handler_count();
     }
 
-    // Validate strict mode. We can do this only after parsing the function,
-    // since the function can declare itself strict.
+    // Validate strict mode.
     if (strict_mode() == STRICT) {
-      if (IsEvalOrArguments(function_name)) {
-        ReportMessageAt(function_name_location, "strict_eval_arguments");
-        *ok = false;
-        return NULL;
-      }
-      if (name_is_strict_reserved) {
-        ReportMessageAt(function_name_location, "unexpected_strict_reserved");
-        *ok = false;
-        return NULL;
-      }
-      if (eval_args_error_log.IsValid()) {
-        ReportMessageAt(eval_args_error_log, "strict_eval_arguments");
-        *ok = false;
-        return NULL;
-      }
-      if (dupe_error_loc.IsValid()) {
-        ReportMessageAt(dupe_error_loc, "strict_param_dupe");
-        *ok = false;
-        return NULL;
-      }
-      if (reserved_loc.IsValid()) {
-        ReportMessageAt(reserved_loc, "unexpected_strict_reserved");
-        *ok = false;
-        return NULL;
-      }
+      CheckStrictFunctionNameAndParameters(function_name,
+                                           name_is_strict_reserved,
+                                           function_name_location,
+                                           eval_args_error_log,
+                                           dupe_error_loc,
+                                           reserved_loc,
+                                           CHECK_OK);
       CheckOctalLiteral(scope->start_position(),
                         scope->end_position(),
                         CHECK_OK);
@@ -3740,6 +3783,7 @@ PreParser::PreParseResult Parser::ParseLazyFunctionBodyWithPreParser(
     reusable_preparser_->set_allow_lazy(true);
     reusable_preparser_->set_allow_generators(allow_generators());
     reusable_preparser_->set_allow_for_of(allow_for_of());
+    reusable_preparser_->set_allow_arrow_functions(allow_arrow_functions());
     reusable_preparser_->set_allow_harmony_numeric_literals(
         allow_harmony_numeric_literals());
   }