code: function integer(token, addTokenToMatch, getNextToken) {
      if (calc(token, addTokenToMatch, getNextToken)) {
          return true;
      }
  
      if (token === null) {
          return false;
      }
  
      var numberEnd = consumeNumber(token.value, false);
      if (numberEnd !== token.value.length) {
          return false;
      }
  
      addTokenToMatch();
      return true;
  }
docs: TODO: fail on 10e-2