var parse = require('ret');
|
var types = parse.types;
|
|
module.exports = function (re, opts) {
|
if (!opts) opts = {};
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var replimit = opts.limit === undefined ? 25 : opts.limit;
|
|
if (isRegExp(re)) re = re.source;
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else if (typeof re !== 'string') re = String(re);
|
|
try { re = parse(re) }
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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]';
|
}
|
