Implement handling of arrow functions in the parser

src/parser.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/api.h"
 #include "src/ast.h"
 #include "src/bootstrapper.h"
 #include "src/char-predicates-inl.h"
@@ skipping 660 matching lines @@
 }
 
 
 const AstString* ParserTraits::GetNextSymbol(Scanner* scanner) {
   return parser_->scanner()->NextSymbol(parser_->ast_value_factory_);
 }
 
 
 Expression* ParserTraits::ThisExpression(
     Scope* scope,
-    AstNodeFactory<AstConstructionVisitor>* factory) {
-  return factory->NewVariableProxy(scope->receiver());
+    AstNodeFactory<AstConstructionVisitor>* factory,
+    int pos) {
+  return factory->NewVariableProxy(scope->receiver(), pos);
 }
 
 
 Literal* ParserTraits::ExpressionFromLiteral(
     Token::Value token, int pos,
     Scanner* scanner,
     AstNodeFactory<AstConstructionVisitor>* factory) {
   switch (token) {
     case Token::NULL_LITERAL:
       return factory->NewNullLiteral(pos);
@@ skipping 82 matching lines @@
       pending_error_arg_(NULL),
       pending_error_char_arg_(NULL) {
   ASSERT(!script_.is_null());
   isolate_->set_ast_node_id(0);
   set_allow_harmony_scoping(!info->is_native() && FLAG_harmony_scoping);
   set_allow_modules(!info->is_native() && FLAG_harmony_modules);
   set_allow_natives_syntax(FLAG_allow_natives_syntax || info->is_native());
   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);
 }
 
 
 FunctionLiteral* Parser::ParseProgram() {
   // TODO(bmeurer): We temporarily need to pass allow_nesting = true here,
   // see comment for HistogramTimerScope class.
   HistogramTimerScope timer_scope(isolate()->counters()->parse(), true);
   Handle<String> source(String::cast(script_->source()));
   isolate()->counters()->total_parse_size()->Increment(source->length());
@@ skipping 2494 matching lines @@
   Smi* literal_type = Smi::cast(value->get(kLiteralTypeSlot));
   return static_cast<LiteralType>(literal_type->value());
 }
 
 
 Handle<FixedArray> CompileTimeValue::GetElements(Handle<FixedArray> value) {
   return Handle<FixedArray>(FixedArray::cast(value->get(kElementsSlot)));
 }
 
 
+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 = "";

[marja, 2014/06/17 11:47:37]

In this case, don't we get an incorrect error end position?

+      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,
     bool name_is_strict_reserved,
     bool is_generator,
     int function_token_pos,
     FunctionLiteral::FunctionType function_type,
     bool* ok) {
   // Function ::
   //   '(' FormalParameterList? ')' '{' FunctionBody '}'
@@ skipping 190 matching lines @@
       SkipLazyFunctionBody(function_name, &materialized_literal_count,
                            &expected_property_count, CHECK_OK);
     } else {
       body = ParseEagerFunctionBody(function_name, pos, fvar, fvar_init_op,
                                     is_generator, CHECK_OK);
       materialized_literal_count = function_state.materialized_literal_count();
       expected_property_count = function_state.expected_property_count();
       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);
     }
     ast_properties = *factory()->visitor()->ast_properties();
     dont_optimize_reason = factory()->visitor()->dont_optimize_reason();
   }
 
   if (allow_harmony_scoping() && strict_mode() == STRICT) {
     CheckConflictingVarDeclarations(scope, CHECK_OK);
@@ skipping 170 matching lines @@
 
   if (reusable_preparser_ == NULL) {
     intptr_t stack_limit = isolate()->stack_guard()->real_climit();
     reusable_preparser_ = new PreParser(&scanner_, NULL, stack_limit);
     reusable_preparser_->set_allow_harmony_scoping(allow_harmony_scoping());
     reusable_preparser_->set_allow_modules(allow_modules());
     reusable_preparser_->set_allow_natives_syntax(allow_natives_syntax());
     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());
   }
   PreParser::PreParseResult result =
       reusable_preparser_->PreParseLazyFunction(strict_mode(),
                                                 is_generator(),
                                                 logger);
   return result;
 }
 
@@ skipping 1096 matching lines @@
   ast_value_factory_->Internalize(isolate());
   // info takes ownership of ast_value_factory_.
   if (info()->ast_value_factory() == NULL) {
     info()->SetAstValueFactory(ast_value_factory_);
   }
   ast_value_factory_ = NULL;
   return (result != NULL);
 }
 
 } }  // namespace v8::internal