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|
{-# OPTIONS -cpp #-}
-----------------------------------------------------------------------------
-- |
-- Module : Text.Regex
-- Copyright : (c) The University of Glasgow 2001
-- License : BSD-style (see the file libraries/base/LICENSE)
--
-- Maintainer : libraries@haskell.org
-- Stability : experimental
-- Portability : non-portable (only on platforms that provide a regex lib)
--
-- Regular expression matching. Uses the POSIX regular expression
-- interface in "Text.Regex.Posix".
--
-----------------------------------------------------------------------------
#include "config.h"
module Text.Regex (
-- * Regular expressions
Regex,
#if !defined(__HUGS__) || defined(HAVE_REGEX_H)
mkRegex,
mkRegexWithOpts,
matchRegex,
matchRegexAll
#endif
) where
import Prelude
import qualified Text.Regex.Posix as RE
import Text.Regex.Posix ( Regex )
import System.IO.Unsafe
#if !defined(__HUGS__) || defined(HAVE_REGEX_H)
-- | Makes a regular expression with the default options (multi-line,
-- case-sensitive). The syntax of regular expressions is
-- otherwise that of @egrep@ (i.e. POSIX \"extended\" regular
-- expressions).
mkRegex :: String -> Regex
mkRegex s = unsafePerformIO (RE.regcomp s RE.regExtended)
-- | Makes a regular expression, where the multi-line and
-- case-sensitve options can be changed from the default settings.
mkRegexWithOpts
:: String -- ^ The regular expression to compile
-> Bool -- ^ 'True' @\<=>@ @\'^\'@ and @\'$\'@ match the beginning and
-- end of individual lines respectively, and @\'.\'@ does /not/
-- match the newline character.
-> Bool -- ^ 'True' @\<=>@ matching is case-sensitive
-> Regex -- ^ Returns: the compiled regular expression
mkRegexWithOpts s single_line case_sensitive
= unsafePerformIO (RE.regcomp s (RE.regExtended + newline + igcase))
where
newline | single_line = RE.regNewline
| otherwise = 0
igcase | case_sensitive = 0
| otherwise = RE.regIgnoreCase
-- | Match a regular expression against a string
matchRegex
:: Regex -- ^ The regular expression
-> String -- ^ The string to match against
-> Maybe [String] -- ^ Returns: @'Just' strs@ if the match succeeded
-- (and @strs@ is the list of subexpression matches),
-- or 'Nothing' otherwise.
matchRegex p str =
case (unsafePerformIO (RE.regexec p str)) of
Nothing -> Nothing
Just (before, match, after, sub_strs) -> Just sub_strs
-- | Match a regular expression against a string, returning more information
-- about the match.
matchRegexAll
:: Regex -- ^ The regular expression
-> String -- ^ The string to match against
-> Maybe ( String, String, String, [String] )
-- ^ Returns: 'Nothing' if the match failed, or:
--
-- > Just ( everything before match,
-- > portion matched,
-- > everything after the match,
-- > subexpression matches )
matchRegexAll p str = unsafePerformIO (RE.regexec p str)
#endif
|
