1 var parse = require('ret');
2 var types = parse.types;
4 module.exports = function (re, opts) {
6 var replimit = opts.limit === undefined ? 25 : opts.limit;
8 if (isRegExp(re)) re = re.source;
9 else if (typeof re !== 'string') re = String(re);
11 try { re = parse(re) }
12 catch (err) { return false }
15 return (function walk (node, starHeight) {
16 if (node.type === types.REPETITION) {
19 if (starHeight > 1) return false;
20 if (reps > replimit) return false;
24 for (var i = 0, len = node.options.length; i < len; i++) {
25 var ok = walk({ stack: node.options[i] }, starHeight);
26 if (!ok) return false;
29 var stack = node.stack || (node.value && node.value.stack);
30 if (!stack) return true;
32 for (var i = 0; i < stack.length; i++) {
33 var ok = walk(stack[i], starHeight);
34 if (!ok) return false;
41 function isRegExp (x) {
42 return {}.toString.call(x) === '[object RegExp]';