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

runtime/vm/scanner.cc

 // Copyright (c) 2012, 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.
 
 #include "vm/scanner.h"
 
 #include "platform/assert.h"
 #include "vm/flags.h"
 #include "vm/object.h"
 #include "vm/thread.h"
@@ skipping 168 matching lines @@
 int32_t Scanner::LookaheadChar(int how_many) {
   ASSERT(how_many >= 0);
   int32_t lookahead_char = '\0';
   if (lookahead_pos_ + how_many < source_length_) {
     lookahead_char = source_.CharAt(lookahead_pos_ + how_many);
   }
   return lookahead_char;
 }
 
 
+static bool IsWhiteSpace(char ch) {

[hausner, 2012/01/31 18:09:46]

This definition of what a whitespace character is differs from the one in the
function below. I find that confusing. I would inline the code in the one place
where it's used below, if you still need it (see comment below).

[srdjan, 2012/01/31 19:26:37]

Discussed the difference offline. Removed the method since we are looking at
IsNumberStart instead.

+  return ch == '\0' || ch == '\n' || ch == '\r' || ch == ' ' || ch == '\t';
+}
+
+
 void Scanner::ConsumeWhiteSpace() {
   while (c0_ == ' ' || c0_ == '\t' || c0_ == '\n') {
     ReadChar();
   }
 }
 
 
 void Scanner::ConsumeLineComment() {
   ASSERT(c0_ == '/');
   while (c0_ != '\n' && c0_ != '\0') {
@@ skipping 387 matching lines @@
         ScanLiteralStringChars(false);
       }
       break;
     }
     switch (c0_) {
       case '\0':
         current_token_.kind = Token::kEOS;
         break;
 
       case '+':  // +  ++  +=
-        Recognize(Token::kADD);
+        ReadChar();
+        current_token_.kind =
+            IsWhiteSpace(c0_) ? Token::kADD : Token::kTIGHTADD;

[hausner, 2012/01/31 18:09:46]

Would it not make more sense to reverse the logic here? That is, a + is kADD
unless it is immediately followed by a digit and possibly a dot (+.5) or
whatever the rules for literals allow. In that case, we make it a kTIGHTADD.

[srdjan, 2012/01/31 19:26:37]

Changed.

         if (c0_ == '+') {
           Recognize(Token::kINCR);
         } else if (c0_ == '=') {
           Recognize(Token::kASSIGN_ADD);
         }
         break;
 
       case '-':  // -  --  -=
         Recognize(Token::kSUB);
         if (c0_ == '-') {
@@ skipping 276 matching lines @@
               "%c%"PRIxPTR, kPrivateKeySeparator, key_value);
   const String& result = String::Handle(String::New(private_key));
   return result.raw();
 }
 
 
 void Scanner::InitOnce() {
 }
 
 }  // namespace dart