[Haskell-beginners] Pure Regex.PCRE Possible? (PLEAC, Fix Style)

Chaddaï Fouché chaddai.fouche at gmail.com
Sun Dec 20 04:16:59 EST 2009

On Sat, Dec 19, 2009 at 2:37 PM, Volkan YAZICI <yazicivo at ttmail.com> wrote:
> However, if I'm not mistaken, above functions _should_ be absolutely
> pure. Is it possible to encapsulate impure PCRE functions into their
> pure equivalents?
> BTW, why are PCRE functions impure?

Mainly because they _are_ the core that _is_ encapsulated as you
suggested : regex-pcre as many other regex library, provides the same
basic mostly pure interface which is in regex-base.

That interface comes with many specific pure function (matchText,
matchOnce, matchAll and so on, as well as makeRegex and others) and
some "magic" operators like =~ which decides what kind of matching you
want to do depending on the type of the result.
See this tutorial for some example of usage :


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