code: function make_regex(tokens) {
  	var str = tokens.reduce(function (res, token, index) {
  			var is_last = (index == (tokens.length - 1));
  			var before_multi = (index === (tokens.length - 2)) && (last(tokens).type == "multi");
  			return res + ((is_last || before_multi) ? token.last : token.piece);
  		},
  		"");
  	return new RegExp("^" + str + "$");
  }
docs: Generates the RegExp object from the tokens