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I find when I move across languages (which happens frequently) or even tools (like grep), regexp implementation often differs enough to throw me off and introdu

by Poleris 17y ago

I find when I move across languages (which happens frequently) or even tools (like grep), regexp implementation often differs enough to throw me off and introduce subtle bugs. Is there a page that shows a mapping between different implementations of regular expressions and which languages and applications they're used in? Is there a better way to figure these things out than hunt for documentation every time?

gustavo_duarte 17y ago
I've written an automated tool to convert Vim-style regexes to Perl-style. This is kind of a dramatic case as the dialect is very different, but it was a fun thing to write.
- staunch 17y ago
  Can you make vim use pcre?
  - gustavo_duarte 17y ago
    From my look in the Vim sources, it would be tons of work to truly make it use pcre internally. But I think it wouldn't be hard to do a plugin that translates a pcre into a Vim regex, allowing you to search or replace using pcres. My code though is not integrated with Vim, it takes a free floating regex and converts it. I used it to convert all the regexes in Vim syntax files and build a syntax highlighter. It was a silly project, just for fun.
- DEinspanjer 17y ago
  Is it bi-directional? Is it on the vim.org website somewhere? I find Vim's escape heavy syntax cumbersome and I frequently wish I could write a quick Perl syntax regex and convert it to Vim. Of course, Vim is one of the few regex engines to support variable width negative look-behinds, so I guess that counts for something. :)
  - gustavo_duarte 17y ago
    Only Vim -> Perl is fully fleshed out right now. Doing it the other way would be fairly easy though because so much would be reused. Also, with the Vim regexes I had to worry about magicness and so on, the Perl stuff would parse easier. It's not in Vim.org. I had the code floating around with an MIT license, but it's offline right now. I thought about building a page where you could do the translation (I figured Perl -> Vim is what people would want more) or just use a simple GET request from other code. Maybe I should do the Perl -> Vim bit and make it available.
zouhair 17y ago
sudo aptitude install txt2regex
0xdefec8 17y ago
indeed. grep -P is your friend. (except older grep versions seem to segfault on me constantly with various -P regexes)
DEinspanjer 17y ago
A tool I find useful enough to warrant purchasing and running in a VM or Wine is RegexBuddy. It is great for debugging / optimizing regexes and supports several different language flavors. Still waiting for Vim and PHP flavors though. :) It allows you to generate code snippits in several languages that use the regex you constructed, and will assist you in performing cross-language translations.

by Poleris 17y ago

gustavo_duarte 17y ago

I've written an automated tool to convert Vim-style regexes to Perl-style. This is kind of a dramatic case as the dialect is very different, but it was a fun thing to write.

staunch 17y ago
Can you make vim use pcre?
- gustavo_duarte 17y ago
  From my look in the Vim sources, it would be tons of work to truly make it use pcre internally. But I think it wouldn't be hard to do a plugin that translates a pcre into a Vim regex, allowing you to search or replace using pcres. My code though is not integrated with Vim, it takes a free floating regex and converts it. I used it to convert all the regexes in Vim syntax files and build a syntax highlighter. It was a silly project, just for fun.
DEinspanjer 17y ago
Is it bi-directional? Is it on the vim.org website somewhere? I find Vim's escape heavy syntax cumbersome and I frequently wish I could write a quick Perl syntax regex and convert it to Vim. Of course, Vim is one of the few regex engines to support variable width negative look-behinds, so I guess that counts for something. :)
- gustavo_duarte 17y ago
  Only Vim -> Perl is fully fleshed out right now. Doing it the other way would be fairly easy though because so much would be reused. Also, with the Vim regexes I had to worry about magicness and so on, the Perl stuff would parse easier. It's not in Vim.org. I had the code floating around with an MIT license, but it's offline right now. I thought about building a page where you could do the translation (I figured Perl -> Vim is what people would want more) or just use a simple GET request from other code. Maybe I should do the Perl -> Vim bit and make it available.

zouhair 17y ago

sudo aptitude install txt2regex

0xdefec8 17y ago

indeed. grep -P is your friend. (except older grep versions seem to segfault on me constantly with various -P regexes)

DEinspanjer 17y ago

A tool I find useful enough to warrant purchasing and running in a VM or Wine is RegexBuddy. It is great for debugging / optimizing regexes and supports several different language flavors. Still waiting for Vim and PHP flavors though. :) It allows you to generate code snippits in several languages that use the regex you constructed, and will assist you in performing cross-language translations.