Improve List implementation.

dart/frog/leg/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.
 
 interface Scanner {
   Token tokenize();
 }
 
 /**
  * Common base class for a Dart scanner.
@@ skipping 444 matching lines @@
         next = tokenizeExponent(advance());
         done = true;
         continue LOOP;
       } else {
         done = true;
         continue LOOP;
       }
       next = advance();
     }
     if (!hasDigit) {
-      appendByteStringToken(INT_INFO, asciiString(start, -2));
+      appendByteStringToken(INT_INFO, asciiString(start, -1));
       // TODO(ahe): Wrong offset for the period.
       appendPrecenceToken(PERIOD_INFO);
       return bigSwitch(next);
     }
     if (next === $d || next === $D) {
       next = advance();
     }
     appendByteStringToken(DOUBLE_INFO, asciiString(start, 0));
     return next;
   }
@@ skipping 272 matching lines @@
                                       charOffset);
   }
 }
 
 class MalformedInputException {
   final String message;
   final position;
   MalformedInputException(this.message, this.position);
   toString() => message;
 }