23 lines
674 B
Haskell
23 lines
674 B
Haskell
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module Misc where
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import qualified System.Console.GetOpt as GetOpt
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import System.Environment
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import System.Exit
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-- | exception on 'Left'
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unwrap :: Show a => FilePath -> Either a b -> IO b
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unwrap file = either (\x -> fail $ file <> ":" <> show x) return
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getOptionsWith :: (String -> String) -> ([String] -> Maybe a)
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-> [GetOpt.OptDescr (a -> a)] -> IO a
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getOptionsWith hdr mkDef descrs = do
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res <- GetOpt.getOpt GetOpt.Permute descrs <$> getArgs
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case res of
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(fs, rest, []) | Just def <- mkDef rest ->
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return $ foldl (flip ($)) def fs
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_ -> do
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prog <- getProgName
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putStrLn $ GetOpt.usageInfo (hdr prog) descrs
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exitFailure
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