Comments on: XRegExp 1.0

By: Jim O'Callaghan

Jim O'Callaghan — Tue, 13 Dec 2011 17:01:59 +0000

Thanks for the great library. I think I found a bug using JQuery 1.7.1 with xregexp 1.5.0, IE6 only – around line 270:

RegExp.prototype.exec = function (str) {
var match = real.exec.apply(this, arguments),

needs to change to:

RegExp.prototype.exec = function (str) {
str = String(str);
var match = real.exec.apply(this, arguments),

This is for ECMAScript standard (section 15.10.6.2). Found the fix on http://blog.slaks.net/2011/09/xregexp-breaks-jquery-animations.html though his solution:

if (!str.slice)
str = String(str);

… caused me problems as slice was undefined under the error condition – the unconditional cast seems to work without issue.

By: lyrics

lyrics — Fri, 05 Aug 2011 21:38:58 +0000

Thanks for all your work! I really appreciate it. It helped me developing websites easily.

By: Regular expressions « Eikonal Blog

Regular expressions « Eikonal Blog — Wed, 27 Apr 2011 16:09:45 +0000

[...] XRegExp by Steven Levithan – http://blog.stevenlevithan.com/archives/xregexp-1-0 [...]

By: Steven Levithan

Steven Levithan — Mon, 02 Nov 2009 15:08:52 +0000

It is not a Java bug, and it is well specified in the specs for Java, JavaScript, and most other regex flavors. In Java, of course, the singleline option is called dotall (a more descriptive and therefore superior name), and JavaScript doesn't have a native equivalent (the /s flag in RegexPal comes from XRegExp, which silently converts the appropriate dots to [\s\S]). Lookahead obeys /m just fine, but /m has no impact on the dot (whereas /s does). I think you are a bit confused about what the /m and /s flags actually do (this is a common point of confusion since the flags are named so terribly). Please see http://blog.stevenlevithan.com/archives/singleline-multiline-confusing for the details. XRegExp("^a(?=.)$", "ms").test("a\n") should and does return true. XRegExp("^a(?!.)$", "ms").test("a\n") should and does return false. This is long-established, cross-library-consistent regex behavior (albeit confusing due to the flag names).

By: Aeron

Aeron — Mon, 02 Nov 2009 09:03:48 +0000

Flags: ms
^a(?=.)$ with “a\n” matches but shouldn’t.
^a(?!.)$ with “a\n” does not match but should.

Imo, with multiline enabled a lookAhead should ignore the line terminator (and the rest of the expression) if the following statement is a ‘$’.