Bulat Ziganshin wrote:
Hello Chris,
Wednesday, August 2, 2006, 3:16:58 PM, you wrote:
Announcing: TextRegexLazy version 0.56
your feature list is really strong! it will be great now to make it
a part of GHC standard distribution
afaiu, selection of regex engine implemented via import statements?
You can actually choose which backend (=~) uses at runtime:
{-# OPTIONS_GHC -fglasgow-exts #-}
import Text.Regex.Lazy
import qualified Text.Regex.PCRE as R
import qualified Text.Regex.PosixRE as S
import qualified Text.Regex.Full as F
-- Choose which library to use depending on presence of PCRE library
(=~) :: (RegexMaker R.Regex R.CompOption R.ExecOption a,RegexContext R.Regex b t
,RegexMaker F.Regex F.CompOption F.ExecOption a,RegexContext F.Regex b t
,RegexMaker S.Regex S.CompOption S.ExecOption a,RegexContext S.Regex b
t)
> => b -> a -> t
(=~) = case R.getVersion of
Just _ -> (R.=~)
Nothing -> case S.getVersion of
Just _ -> (S.=~)
Nothing -> (F.=~)
main = print (("ba" =~ "(.)a") :: (String,String,String,[String]))
The R.getVersion and S.getVersion detect whether it was compiled against PCRE or
PosixRE. The (=~) is then chosen at run time.
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