var parse = require('ret'); var types = parse.types; module.exports = function (re, opts) { if (!opts) opts = {}; var replimit = opts.limit === undefined ? 25 : opts.limit; if (isRegExp(re)) re = re.source; else if (typeof re !== 'string') re = String(re); try { re = parse(re) } catch (err) { return false } var reps = 0; return (function walk (node, starHeight) { if (node.type === types.REPETITION) { starHeight ++; reps ++; if (starHeight > 1) return false; if (reps > replimit) return false; } if (node.options) { for (var i = 0, len = node.options.length; i < len; i++) { var ok = walk({ stack: node.options[i] }, starHeight); if (!ok) return false; } } var stack = node.stack || (node.value && node.value.stack); if (!stack) return true; for (var i = 0; i < stack.length; i++) { var ok = walk(stack[i], starHeight); if (!ok) return false; } return true; })(re, 0); }; function isRegExp (x) { return {}.toString.call(x) === '[object RegExp]'; }