{-# OPTIONS_GHC -fno-warn-orphans #-} ----------------------------------------------------------------------------- -- | -- Module : Text.Regex.Posix.String -- Copyright : (c) Chris Kuklewicz 2006 -- License : BSD-style (see the file LICENSE) -- -- Maintainer : libraries@haskell.org, textregexlazy@personal.mightyreason.com -- Stability : experimental -- Portability : non-portable (regex-base needs MPTC+FD) -- -- This provides 'String' instances for 'RegexMaker' and 'RegexLike' based -- on "Text.Regex.Posix.Wrap", and a ('RegexContext' 'Regex' 'String' 'String') -- instance. -- -- To use these instance, you would normally import -- "Text.Regex.Posix". You only need to import this module to use -- the medium level API of the compile, regexec, and execute -- functions. All of these report error by returning Left values -- instead of undefined or error or fail. -- ----------------------------------------------------------------------------- module Text.Regex.Posix.String( -- ** Types Regex, MatchOffset, MatchLength, ReturnCode, WrapError, -- ** Miscellaneous unusedOffset, -- ** Medium level API functions compile, regexec, execute, -- ** Compilation options CompOption(CompOption), compBlank, compExtended, -- use extended regex syntax compIgnoreCase, -- ignore case when matching compNoSub, -- no substring matching needed compNewline, -- '.' doesn't match newline -- ** Execution options ExecOption(ExecOption), execBlank, execNotBOL, -- not at begining of line execNotEOL -- not at end of line ) where import Data.Array(listArray, Array) import Data.List(genericDrop, genericTake) import Foreign.C.String(withCAString) import System.IO.Unsafe(unsafePerformIO) import Text.Regex.Base.RegexLike(RegexContext(..),RegexMaker(..),RegexLike(..),MatchOffset,MatchLength) import Text.Regex.Posix.Wrap import Text.Regex.Base.Impl(polymatch,polymatchM) instance RegexContext Regex String String where match = polymatch matchM = polymatchM unusedOffset :: Int unusedOffset = fromIntegral unusedRegOffset unwrap :: (Show e) => Either e v -> IO v unwrap x = case x of Left err -> fail ("Text.Regex.Posix.String died: "++ show err) Right v -> return v instance RegexMaker Regex CompOption ExecOption String where makeRegexOpts c e pattern = unsafePerformIO $ (compile c e pattern >>= unwrap) makeRegexOptsM c e pattern = either (fail.show) return $ unsafePerformIO $ (compile c e pattern) instance RegexLike Regex String where matchTest regex str = unsafePerformIO $ do withCAString str (wrapTest regex) >>= unwrap matchOnce regex str = unsafePerformIO $ execute regex str >>= unwrap matchAll regex str = unsafePerformIO $ withCAString str (wrapMatchAll regex) >>= unwrap matchCount regex str = unsafePerformIO $ withCAString str (wrapCount regex) >>= unwrap -- compile compile :: CompOption -- ^ Flags (summed together) -> ExecOption -- ^ Flags (summed together) -> String -- ^ The regular expression to compile (ASCII only, no null bytes) -> IO (Either WrapError Regex) -- ^ Returns: the compiled regular expression compile flags e pattern = withCAString pattern (wrapCompile flags e) -- ----------------------------------------------------------------------------- -- regexec -- | Matches a regular expression against a string execute :: Regex -- ^ Compiled regular expression -> String -- ^ String to match against -> IO (Either WrapError (Maybe (Array Int (MatchOffset,MatchLength)))) -- ^ Returns: 'Nothing' if the regex did not match the -- string, or: -- -- @ -- 'Just' (array of offset length pairs) -- @ execute regex str = do maybeStartEnd <- withCAString str (wrapMatch regex) case maybeStartEnd of Right Nothing -> return (Right Nothing) -- Right (Just []) -> fail "got [] back!" -- return wierd array instead Right (Just parts) -> return . Right . Just . listArray (0,pred (length parts)) . map (\(s,e)->(fromIntegral s, fromIntegral (e-s))) $ parts Left err -> return (Left err) -- ----------------------------------------------------------------------------- -- regexec -- | Matches a regular expression against a string regexec :: Regex -- ^ Compiled regular expression -> String -- ^ String to match against -> IO (Either WrapError (Maybe (String, String, String, [String]))) -- ^ Returns: 'Nothing' if the regex did not match the -- string, or: -- -- @ -- 'Just' (everything before match, -- matched portion, -- everything after match, -- subexpression matches) -- @ regexec regex str = do let getSub (start,stop) | start == unusedRegOffset = "" | otherwise = genericTake (stop-start) . genericDrop start $ str matchedParts [] = (str,"","",[]) -- no information matchedParts (matchedStartStop@(start,stop):subStartStop) = (genericTake start str ,getSub matchedStartStop ,genericDrop stop str ,map getSub subStartStop) maybeStartEnd <- withCAString str (wrapMatch regex) case maybeStartEnd of Right Nothing -> return (Right Nothing) Right (Just parts) -> return . Right . Just . matchedParts $ parts Left err -> return (Left err)