31 lines
868 B
Haskell
31 lines
868 B
Haskell
{-# LANGUAGE ScopedTypeVariables #-}
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module Language.Haskell.GhcMod.GHCChoice where
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import Control.Exception
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import CoreMonad
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import Exception
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import GHC
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----------------------------------------------------------------
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-- | Try the left 'Ghc' action. If 'IOException' occurs, try
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-- the right 'Ghc' action.
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(||>) :: Ghc a -> Ghc a -> Ghc a
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x ||> y = x `gcatch` (\(_ :: IOException) -> y)
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-- | Go to the next 'Ghc' monad by throwing 'AltGhcgoNext'.
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goNext :: Ghc a
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goNext = liftIO . throwIO $ userError "goNext"
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-- | Run any one 'Ghc' monad.
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runAnyOne :: [Ghc a] -> Ghc a
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runAnyOne = foldr (||>) goNext
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----------------------------------------------------------------
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-- | Try the left 'GhcMonad' action. If 'IOException' occurs, try
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-- the right 'GhcMonad' action.
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(|||>) :: GhcMonad m => m a -> m a -> m a
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x |||> y = x `gcatch` (\(_ :: IOException) -> y)
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