Implement parsing of ES6 Rest Parameters

src/scanner.cc

 // Copyright 2011 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.
 
 // Features shared by parsing and pre-parsing scanners.
 
 #include <stdint.h>
 
 #include <cmath>
 
@@ skipping 581 matching lines @@
         token = Select('=', Token::ASSIGN_BIT_XOR, Token::BIT_XOR);
         break;
 
       case '.':
         // . Number
         Advance();
         if (IsDecimalDigit(c0_)) {
           token = ScanNumber(true);
         } else {
           token = Token::PERIOD;
+          if (c0_ == '.') {

[arv (Not doing code reviews), 2015/01/30 05:28:13]

With this we change the error message in the following case:

  a...b

from

  SyntaxError: Unexpected token .

to

  SyntaxError: Unexpected token ...

I'm not sure that is a big deal though.

[marja, 2015/01/30 08:33:31]

Maybe that's a reason to at least check the harmony flag here so that that error
would only occur when the flag is on? (But I don't think it's a hugely important
thing either.)

+            Advance();
+            if (c0_ == '.') {
+              Advance();
+              token = Token::ELLIPSIS;
+            } else {
+              PushBack('.');
+            }
+          }
         }
         break;
 
       case ':':
         token = Select(Token::COLON);
         break;
 
       case ';':
         token = Select(Token::SEMICOLON);
         break;
@@ skipping 866 matching lines @@
     }
     backing_store_.Add(static_cast<uint8_t>((one_byte_length >> 7) | 0x80u));
   }
   backing_store_.Add(static_cast<uint8_t>(one_byte_length & 0x7f));
 
   backing_store_.AddBlock(bytes);
   return backing_store_.EndSequence().start();
 }
 
 } }  // namespace v8::internal