Comments on: Regular expressions http://www.texdev.net/2009/05/30/regular-expressions/ Coding in the TeX world Tue, 20 Jul 2010 18:48:03 +0000 hourly 1 http://wordpress.org/?v=abc By: Joseph Wright http://www.texdev.net/2009/05/30/regular-expressions/comment-page-1/#comment-1010 Joseph Wright Thu, 04 Jun 2009 14:34:19 +0000 http://www.texdev.net/?p=302#comment-1010 Makes sense: I was after a look-behind one. Shame they are not available. Makes sense: I was after a look-behind one. Shame they are not available.

]]> By: Tomek http://www.texdev.net/2009/05/30/regular-expressions/comment-page-1/#comment-1009 Tomek Thu, 04 Jun 2009 14:25:33 +0000 http://www.texdev.net/?p=302#comment-1009 After some more careful study of Qt docs I've found out that only lookahead assertions are supported but not lookbehind (which would be much more useful for TeX sources). After some more careful study of Qt docs I’ve found out that only lookahead assertions are supported but not lookbehind (which would be much more useful for TeX sources).

]]> By: Joseph Wright http://www.texdev.net/2009/05/30/regular-expressions/comment-page-1/#comment-1008 Joseph Wright Thu, 04 Jun 2009 13:20:15 +0000 http://www.texdev.net/?p=302#comment-1008 I'm not a big regex person either, but in TeX it is hard to do search and replace for strings rather than tokens. So I see why newer engines provide something. I've also had some struggles with the TeXworks regex engine: I also wanted some look behind things. There was some discussion on the mailing list, but I'm not sure what the result was. I think TeXworks just loads a regex parser, but perhaps the Qt version is different or something. I’m not a big regex person either, but in TeX it is hard to do search and replace for strings rather than tokens. So I see why newer engines provide something.

I’ve also had some struggles with the TeXworks regex engine: I also wanted some look behind things. There was some discussion on the mailing list, but I’m not sure what the result was. I think TeXworks just loads a regex parser, but perhaps the Qt version is different or something.

]]> By: Tomek http://www.texdev.net/2009/05/30/regular-expressions/comment-page-1/#comment-1007 Tomek Thu, 04 Jun 2009 12:07:12 +0000 http://www.texdev.net/?p=302#comment-1007 I'm not a big fun of regex. Similarly to TeX language, regular expressions feel fine for simple stuff but once you try to do something more complex... Well, if anything can challenge TeX in code obscurity, then regex language must be it. And the fact that, as you say, everybody seems to use a different flavour of this language doesn't help either. BTW, do you know which flavour is supported by TeXworks? I thought it uses Qt specs but just the other day I played with syntax highlighting patterns and wanted to use look ahead/behind matching to colour environment names separately from \begin / \end commands. This should be supported according to Qt docs but it didn't work for me. I’m not a big fun of regex. Similarly to TeX language, regular expressions feel fine for simple stuff but once you try to do something more complex… Well, if anything can challenge TeX in code obscurity, then regex language must be it. And the fact that, as you say, everybody seems to use a different flavour of this language doesn’t help either.

BTW, do you know which flavour is supported by TeXworks? I thought it uses Qt specs but just the other day I played with syntax highlighting patterns and wanted to use look ahead/behind matching to colour environment names separately from \begin / \end commands. This should be supported according to Qt docs but it didn’t work for me.

]]> By: Joseph Wright http://www.texdev.net/2009/05/30/regular-expressions/comment-page-1/#comment-1001 Joseph Wright Tue, 02 Jun 2009 13:50:53 +0000 http://www.texdev.net/?p=302#comment-1001 That's one way to look at it. Of course, they have programmed it in the past: \pdfmatch is a regex matching primitive. I'm not sure anyone uses it, thought! That’s one way to look at it. Of course, they have programmed it in the past: \pdfmatch is a regex matching primitive. I’m not sure anyone uses it, thought!

]]> By: Vafa Khalighi http://www.texdev.net/2009/05/30/regular-expressions/comment-page-1/#comment-1000 Vafa Khalighi Tue, 02 Jun 2009 13:37:04 +0000 http://www.texdev.net/?p=302#comment-1000 Whenever, the luatex team can not program something, they will say that has to be done in lua! (sorry for that, but it is what I feel!) Whenever, the luatex team can not program something, they will say that has to be done in lua! (sorry for that, but it is what I feel!)

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