Fix dart2js decimal number tokenization.

sdk/lib/_internal/compiler/implementation/scanner/scanner.dart

 // 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.
 
 part of scanner;
 
 abstract class Scanner {
   Token tokenize();
 }
 
@@ skipping 444 matching lines @@
     } else {
       appendBeginGroup(LT_INFO, "<");
       return next;
     }
   }
 
   int tokenizeNumber(int next) {
     int start = byteOffset;
     while (true) {
       next = advance();
+      int nextnext = peek();

[ahe, 2013/09/06 14:20:26]

Can you avoid calling peek until you see a '.'?

       if ($0 <= next && next <= $9) {
         continue;
-      } else if (identical(next, $PERIOD)) {
+      } else if (identical(next, $PERIOD)

[ahe, 2013/09/06 14:20:26]

Would this work:

} else if (identical(next, $PERIOD)) {
  int nextnext = peek();
  if ($0 <= nextnext && nextnext <= $9) {
    return tokenizeFractionPart(advance(), start);
  }
  appendByteStringToken(INT_INFO, asciiString(start, 0));
  return next;
} else if ...

This duplicates code, but reduces look-ahead.

+                  && ($0 <= nextnext && nextnext <= $9)) {
         return tokenizeFractionPart(advance(), start);
-      } else if (identical(next, $e) || identical(next, $E)
-          || identical(next, $d) || identical(next, $D)) {
+      } else if (identical(next, $e) || identical(next, $E)) {
         return tokenizeFractionPart(next, start);
       } else {
         appendByteStringToken(INT_INFO, asciiString(start, 0));
         return next;
       }
     }
   }
 
   int tokenizeHexOrNumber(int next) {
     int x = peek();
@@ skipping 55 matching lines @@
     }
     if (!hasDigit) {
       appendByteStringToken(INT_INFO, asciiString(start, -1));
       if (identical($PERIOD, next)) {
         return select($PERIOD, PERIOD_PERIOD_PERIOD_INFO, PERIOD_PERIOD_INFO);
       }
       // TODO(ahe): Wrong offset for the period.
       appendPrecedenceToken(PERIOD_INFO);
       return bigSwitch(next);
     }
-    if (identical(next, $d) || identical(next, $D)) {
-      next = advance();
-    }
     appendByteStringToken(DOUBLE_INFO, asciiString(start, 0));
     return next;
   }
 
   int tokenizeExponent(int next) {
     if (identical(next, $PLUS) || identical(next, $MINUS)) {
       next = advance();
     }
     bool hasDigits = false;
     while (true) {
@@ skipping 277 matching lines @@
       next = advance();
     }
     return error(const SourceString("unterminated string literal"));
   }
 
   int error(SourceString message) {
     appendByteStringToken(BAD_INPUT_INFO, message);
     return advance(); // Ensure progress.
   }
 }