slevithan

// Simulating infinite-length leading lookbehind in JavaScript. Uses XRegExp
// and XRegExp.matchRecursive. Any regex pattern can be used within lookbehind,
// including nested groups. Captures within lookbehind are not included in
// match results. Lazy repetition in lookbehind may lead to unexpected results.

(function (XRegExp) {

    function preparePattern(pattern, flags) {
        var lbOpen, lbEndPos, lbInner;
        flags = flags || "";