code: function(type, val){
      var res = {type: type, line: this.lineno, col: this.colno};
  
      if (val !== undefined) res.val = val;
  
      return res;
    }
docs: Construct a token with the given `type` and `val`.
  
  @param {String} type
  @param {String} val
  @return {Object}
  @api private