So, I tweaked Text.Regex to have the behavior I need. http://patch-tag.com/repo/haskell-learning/browse/regexStuff/pcreReplace.hs FWIW, the problem I was trying to solve was deleting single newlines but not strings of newlines in a document. Dead simple for pcre-regex with lookaround. But, I think, impossible with posix regex. -- replace single newlines, but not strings of newlines (requires pcre look-around (lookaround, lookahead, lookbehind, for googlebot)) http://perldoc.perl.org/perlre.html testPcre = ( subRegex (mkRegex "(?:
Right, I'm just saying that a "subRegex" that worked on pcre regex matches would be great for people used to perl regexen and unused to posix -- even it only allowed a string replacement, and didn't have all the bells and whistles of =~ s../../../ in perl.
2009/3/12 ChrisK
Thomas Hartman wrote:
Is there something like subRegex... something like =~ s/.../.../ in perl... for haskell pcre Regexen?
I mean, subRegex from Text.Regex of course: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/regex-compat
Thanks for any advice,
thomas.
Short answer: No.
This is a FAQ. The usual answer to your follow up "Why not?" is that the design space is rather huge. Rather than justify this statement, I will point at the complicated module:
http://hackage.haskell.org/packages/archive/split/0.1.1/doc/html/Data-List-S...
The above module is "a wide range of strategies for splitting lists", which is a much simpler problem than your subRegex request, and only works on lists. A subRegex library should also work on bytestrings (and Seq).
At the cost of writing your own routine you get exactly what you want in a screen or less of code, see http://hackage.haskell.org/packages/archive/regex-compat/0.92/doc/html/src/T... for "subRegex" which is 30 lines of code.
Cheers, Chris