code: function(regexp, type){
      var captures;
      if (captures = regexp.exec(this.input)) {
        var len = captures[0].length;
        var val = captures[1];
        var diff = len - (val ? val.length : 0);
        var tok = this.tok(type, val);
        this.consume(len);
        this.incrementColumn(diff);
        return tok;
      }
    }
docs: Scan for `type` with the given `regexp`.
  
  @param {String} type
  @param {RegExp} regexp
  @return {Object}
  @api private