[modules] Support parsing anonymous default exports

src/parsing/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/parsing/parser.h"
 
 #include "src/api.h"
 #include "src/ast/ast.h"
 #include "src/ast/ast-expression-rewriter.h"
 #include "src/ast/ast-expression-visitor.h"
@@ skipping 1257 matching lines @@
   }
 
   switch (peek()) {
     case Token::FUNCTION:
       return ParseFunctionDeclaration(NULL, ok);
     case Token::CLASS:
       if (scope_->class_declaration_group_start() < 0) {
         scope_->set_class_declaration_group_start(
             scanner()->peek_location().beg_pos);
       }
+      Consume(Token::CLASS);
       return ParseClassDeclaration(NULL, ok);
     case Token::CONST:
       if (allow_const()) {
         return ParseVariableStatement(kStatementListItem, NULL, ok);
       }
       break;
     case Token::VAR:
       return ParseVariableStatement(kStatementListItem, NULL, ok);
     case Token::LET:
       if (IsNextLetKeyword()) {
@@ skipping 265 matching lines @@
 Statement* Parser::ParseExportDefault(bool* ok) {
   //  Supports the following productions, starting after the 'default' token:
   //    'export' 'default' FunctionDeclaration
   //    'export' 'default' ClassDeclaration
   //    'export' 'default' AssignmentExpression[In] ';'
 
   Expect(Token::DEFAULT, CHECK_OK);
   Scanner::Location default_loc = scanner()->location();
 
   ZoneList<const AstRawString*> names(1, zone());
-  Statement* result = NULL;
+  Statement* result = nullptr;
+  Expression* default_export = nullptr;
   switch (peek()) {
-    case Token::FUNCTION:
-      // TODO(ES6): Support parsing anonymous function declarations here.
-      result = ParseFunctionDeclaration(&names, CHECK_OK);
+    case Token::FUNCTION: {
+      Consume(Token::FUNCTION);
+      int pos = position();
+      bool is_generator = Check(Token::MUL);
+      if (peek() == Token::LPAREN) {
+        // FunctionDeclaration[+Default] ::
+        //   'function' '(' FormalParameters ')' '{' FunctionBody '}'
+        //
+        // GeneratorDeclaration[+Default] ::
+        //   'function' '*' '(' FormalParameters ')' '{' FunctionBody '}'
+        default_export = ParseFunctionLiteral(

[caitp (gmail), 2016/01/14 23:12:53]

per 14.1.20, you probably want the SetFunctionName(F, "default") here, rather
than passing nullptr for the name

[adamk, 2016/01/15 00:06:29]

Done.

+            nullptr, scanner()->location(), kSkipFunctionNameCheck,
+            is_generator ? FunctionKind::kGeneratorFunction
+                         : FunctionKind::kNormalFunction,
+            pos, FunctionLiteral::kDeclaration, FunctionLiteral::kNormalArity,
+            language_mode(), CHECK_OK);
+        result = factory()->NewEmptyStatement(RelocInfo::kNoPosition);
+      } else {
+        result = ParseFunctionDeclaration(pos, is_generator, &names, CHECK_OK);
+      }
       break;
+    }
 
     case Token::CLASS:
-      // TODO(ES6): Support parsing anonymous class declarations here.
-      result = ParseClassDeclaration(&names, CHECK_OK);
+      Consume(Token::CLASS);
+      if (peek() == Token::EXTENDS || peek() == Token::LBRACE) {
+        // ClassDeclaration[+Default] ::
+        //   'class' ('extends' LeftHandExpression)? '{' ClassBody '}'
+        default_export = ParseClassLiteral(

[caitp (gmail), 2016/01/14 23:12:53]

here too, per 15.2.3.11

[adamk, 2016/01/15 00:06:29]

Done.

+            nullptr, Scanner::Location::invalid(), false, position(), CHECK_OK);
+        result = factory()->NewEmptyStatement(RelocInfo::kNoPosition);
+      } else {
+        result = ParseClassDeclaration(&names, CHECK_OK);
+      }
       break;
 
     default: {
       int pos = peek_position();
       ExpressionClassifier classifier;
       Expression* expr = ParseAssignmentExpression(true, &classifier, CHECK_OK);
       expr = ParserTraits::RewriteNonPattern(expr, &classifier, CHECK_OK);
 
       ExpectSemicolon(CHECK_OK);
       result = factory()->NewExpressionStatement(expr, pos);
       break;
     }
   }
 
   const AstRawString* default_string = ast_value_factory()->default_string();
 
   DCHECK_LE(names.length(), 1);
   if (names.length() == 1) {
     scope_->module()->AddLocalExport(default_string, names.first(), zone(), ok);
     if (!*ok) {
       ParserTraits::ReportMessageAt(
           default_loc, MessageTemplate::kDuplicateExport, default_string);
-      return NULL;
+      return nullptr;
     }
   } else {
     // TODO(ES6): Assign result to a const binding with the name "*default*"
     // and add an export entry with "*default*" as the local name.
+    USE(default_export);
   }
 
   return result;
 }
 
 
 Statement* Parser::ParseExportDeclaration(bool* ok) {
   // ExportDeclaration:
   //    'export' '*' 'from' ModuleSpecifier ';'
   //    'export' ExportClause ('from' ModuleSpecifier)? ';'
@@ skipping 70 matching lines @@
         }
       }
       return factory()->NewEmptyStatement(pos);
     }
 
     case Token::FUNCTION:
       result = ParseFunctionDeclaration(&names, CHECK_OK);
       break;
 
     case Token::CLASS:
+      Consume(Token::CLASS);
       result = ParseClassDeclaration(&names, CHECK_OK);
       break;
 
     case Token::VAR:
     case Token::LET:
     case Token::CONST:
       result = ParseVariableStatement(kStatementListItem, &names, CHECK_OK);
       break;
 
     default:
@@ skipping 383 matching lines @@
   NativeFunctionLiteral* lit = factory()->NewNativeFunctionLiteral(
       name, extension_, RelocInfo::kNoPosition);
   return factory()->NewExpressionStatement(
       factory()->NewAssignment(Token::INIT, proxy, lit, RelocInfo::kNoPosition),
       pos);
 }
 
 
 Statement* Parser::ParseFunctionDeclaration(
     ZoneList<const AstRawString*>* names, bool* ok) {
-  // FunctionDeclaration ::
-  //   'function' Identifier '(' FormalParameterListopt ')' '{' FunctionBody '}'
-  // GeneratorDeclaration ::
-  //   'function' '*' Identifier '(' FormalParameterListopt ')'
-  //      '{' FunctionBody '}'
   Expect(Token::FUNCTION, CHECK_OK);
   int pos = position();
   bool is_generator = Check(Token::MUL);
+  return ParseFunctionDeclaration(pos, is_generator, names, ok);
+}
+
+
+Statement* Parser::ParseFunctionDeclaration(
+    int pos, bool is_generator, ZoneList<const AstRawString*>* names,
+    bool* ok) {
+  // FunctionDeclaration ::
+  //   'function' Identifier '(' FormalParameters ')' '{' FunctionBody '}'
+  // GeneratorDeclaration ::
+  //   'function' '*' Identifier '(' FormalParameters ')' '{' FunctionBody '}'
+  //
+  // 'function' and '*' (if present) have been consumed by the caller.
   bool is_strict_reserved = false;
   const AstRawString* name = ParseIdentifierOrStrictReservedWord(
       &is_strict_reserved, CHECK_OK);
 
   FuncNameInferrer::State fni_state(fni_);
   if (fni_ != NULL) fni_->PushEnclosingName(name);
   FunctionLiteral* fun = ParseFunctionLiteral(
       name, scanner()->location(),
       is_strict_reserved ? kFunctionNameIsStrictReserved
                          : kFunctionNameValidityUnknown,
@@ skipping 30 matching lines @@
   }
   return empty;
 }
 
 
 Statement* Parser::ParseClassDeclaration(ZoneList<const AstRawString*>* names,
                                          bool* ok) {
   // ClassDeclaration ::
   //   'class' Identifier ('extends' LeftHandExpression)? '{' ClassBody '}'
   //
+  // 'class' is expected to be consumed by the caller.
+  //
   // A ClassDeclaration
   //
   //   class C { ... }
   //
   // has the same semantics as:
   //
   //   let C = class C { ... };
   //
   // so rewrite it as such.
 
-  Expect(Token::CLASS, CHECK_OK);
   if (!allow_harmony_sloppy() && is_sloppy(language_mode())) {
     ReportMessage(MessageTemplate::kSloppyLexical);
     *ok = false;
     return NULL;
   }
 
   int pos = position();
   bool is_strict_reserved = false;
   const AstRawString* name =
       ParseIdentifierOrStrictReservedWord(&is_strict_reserved, CHECK_OK);
@@ skipping 3526 matching lines @@
     auto class_literal = value->AsClassLiteral();
     if (class_literal->raw_name() == nullptr) {
       class_literal->set_raw_name(name);
     }
   }
 }
 
 
 }  // namespace internal
 }  // namespace v8