Fix for bug 1229: Unary operator plus is not allowed ... except for literals.

runtime/vm/scanner.h

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 //
 // Scanner class for the Dart language. The scanner reads source text
 // and produces a stream of tokens which is used by the parser.
 //
 
 #ifndef VM_SCANNER_H_
 #define VM_SCANNER_H_
@@ skipping 113 matching lines @@
 
   void ErrorMsg(const char* msg);
 
   // Scans entire source into a given stream of tokens.
   void ScanAll(GrowableTokenStream* token_stream);
 
   // These functions return true if the given character is a letter,
   // a decimal digit, a hexadecimal digit, etc.
   static bool IsLetter(int32_t c);
   static bool IsDecimalDigit(int32_t c);
+  static bool IsNumberStart(int32_t);
   static bool IsHexDigit(int32_t c);
   static bool IsIdentStartChar(int32_t c);
   static bool IsIdentChar(int32_t c);
 
   // Skips up to next non-whitespace character.
   void ConsumeWhiteSpace();
 
   // Skips characters up to end of line.
   void ConsumeLineComment();
 
@@ skipping 61 matching lines @@
   const String& private_key_;
 
   SourcePosition c0_pos_;      // Source position of lookahead character c0_.
   KeywordTable keywords_[Token::numKeywords];
 };
 
 
 }  // namespace dart
 
 #endif  // VM_SCANNER_H_