Comments on: Mimicking Atomic Groups http://blog.stevenlevithan.com/archives/mimic-atomic-groups A JavaScript and regular expression centric blog Thu, 11 Mar 2010 18:49:10 +0000 http://wordpress.org/?v=2.9.1 hourly 1 By: Jason http://blog.stevenlevithan.com/archives/mimic-atomic-groups/comment-page-1#comment-17278 Jason Fri, 11 Apr 2008 16:42:16 +0000 http://blog.stevenlevithan.com/?p=15#comment-17278 Thanks for the post. My situation was somewhat different: I did not have the need to fake an aotmic group, but since the .Net RegEx engine does not support possessive quantifiers, I was able to achieve the same results using your atomic groups sample. Thanks again. Thanks for the post. My situation was somewhat different: I did not have the need to fake an aotmic group, but since the .Net RegEx engine does not support possessive quantifiers, I was able to achieve the same results using your atomic groups sample. Thanks again.

]]> By: Steve http://blog.stevenlevithan.com/archives/mimic-atomic-groups/comment-page-1#comment-8731 Steve Thu, 29 Nov 2007 17:34:57 +0000 http://blog.stevenlevithan.com/?p=15#comment-8731 Absolutely (in fact I mentioned them in the post), but since possessive quantifiers are really just a notational convenience, I could get into a semantic argument about if using syntax less convenient than a regular atomic grouping can really be considered to be emulating a notational convenience. Absolutely (in fact I mentioned them in the post), but since possessive quantifiers are really just a notational convenience, I could get into a semantic argument about if using syntax less convenient than a regular atomic grouping can really be considered to be emulating a notational convenience.

]]> By: liorean http://blog.stevenlevithan.com/archives/mimic-atomic-groups/comment-page-1#comment-8711 liorean Thu, 29 Nov 2007 09:35:26 +0000 http://blog.stevenlevithan.com/?p=15#comment-8711 Of course, since possessive quantifiers are semantically equivalent to regular quantifiers in atomic groups, possessive quantifiers can be emulated using the same pattern, too. Of course, since possessive quantifiers are semantically equivalent to regular quantifiers in atomic groups, possessive quantifiers can be emulated using the same pattern, too.

]]> By: Steve http://blog.stevenlevithan.com/archives/mimic-atomic-groups/comment-page-1#comment-8637 Steve Wed, 28 Nov 2007 14:57:34 +0000 http://blog.stevenlevithan.com/?p=15#comment-8637 @nic, Safari 3 supports atomic groups, but no other browser I've tested does, and they're not in the ECMAScript 3 or proposed ECMAScript 4 specs. BTW, since posting this I've learned that emulating atomic groups using capturing groups in lookahead is actually a fairly well-known trick. It's mentioned in the official Perl documentation, as well as in Jeffrey Friedl's <em>Mastering Regular Expressions</em>. See my post just after this one, <a href="/archives/mimic-conditionals" rel="nofollow">Mimicking Conditionals</a>, for another cool trick which I haven't seen elsewhere. @nic, Safari 3 supports atomic groups, but no other browser I’ve tested does, and they’re not in the ECMAScript 3 or proposed ECMAScript 4 specs.

BTW, since posting this I’ve learned that emulating atomic groups using capturing groups in lookahead is actually a fairly well-known trick. It’s mentioned in the official Perl documentation, as well as in Jeffrey Friedl’s Mastering Regular Expressions.

See my post just after this one, Mimicking Conditionals, for another cool trick which I haven’t seen elsewhere.

]]> By: nic_tester http://blog.stevenlevithan.com/archives/mimic-atomic-groups/comment-page-1#comment-8617 nic_tester Wed, 28 Nov 2007 08:44:40 +0000 http://blog.stevenlevithan.com/?p=15#comment-8617 If this works im in awe. I was pretty shocked that javascript does not support atomic groups, took me a long time to realise, it does apear like it would in the references ive found but all my testing sugests otherwise. You just saved my day, well, actually, probably saved me several days. If this works im in awe. I was pretty shocked that javascript does not support atomic groups, took me a long time to realise, it does apear like it would in the references ive found but all my testing sugests otherwise. You just saved my day, well, actually, probably saved me several days.

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