[Haskell-cafe] Using regexps to filter data

[michael rice]

Found this tutorial: http://www.serpentine.com/blog/2007/02/27/a-haskell-regular-expression-tutorial/

Seems to work for what I need to do.

Michael

=========

[michael at localhost ~]$ ghci
GHCi, version 6.10.4: http://www.haskell.org/ghc/  :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer ... linking ... done.
Loading package base ... linking ... done.
Prelude> :mod +Text.Regex.Posix
Prelude Text.Regex.Posix> "bar" =~ "(foo|bar)" :: Bool
Loading package syb ... linking ... done.
Loading package array-0.2.0.0 ... linking ... done.
Loading package bytestring-0.9.1.4 ... linking ... done.
Loading package regex-base-0.72.0.2 ... linking ... done.
Loading package regex-posix-0.72.0.3 ... linking ... done.
True
Prelude Text.Regex.Posix> "-123" =~ "\-?[0-9]+" :: Bool

<interactive>:1:13:
    lexical error in string/character literal at character '?'
Prelude Text.Regex.Posix> "-123" =~ "[+-]?[0-9]+" :: Bool
True
Prelude Text.Regex.Posix> "+123" =~ "[+-]?[0-9]+" :: Bool
True
Prelude Text.Regex.Posix> "abc" =~ "[+-]?[0-9]+" :: Bool 
False
Prelude Text.Regex.Posix> 



--- On Mon, 3/15/10, Stephen Tetley <stephen.tetley at gmail.com> wrote:

From: Stephen Tetley <stephen.tetley at gmail.com>
Subject: Re: [Haskell-cafe] Using regexps to filter data
To: "michael rice" <nowgate at yahoo.com>
Cc: haskell-cafe at haskell.org
Date: Monday, March 15, 2010, 10:09 AM

On 15 March 2010 14:02, michael rice <nowgate at yahoo.com> wrote:
>
> Thanks. Looks kind of complicated. Are there any examples of how to use this stuff?

Hi Michael

I'm note sure, I haven't used the Regex package since it was moved out
of the libs distributed with GHC. I think the multiple backends were
added after this, and it was extended so matching could work on
ByteStrings as well as Strings.

PCRE-light is a simpler alternative, if you can live with PCRE style
regexs rather than Posix ones:

http://hackage.haskell.org/package/pcre-light


Best wishes

Stephen



      
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