forked from mirrors/nixpkgs
24 lines
905 B
Diff
24 lines
905 B
Diff
diff --git a/src/Data/ProtoLens/Encoding/Parser/Internal.hs b/src/Data/ProtoLens/Encoding/Parser/Internal.hs
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index 30eeaad..f2703e7 100644
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--- a/src/Data/ProtoLens/Encoding/Parser/Internal.hs
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+++ b/src/Data/ProtoLens/Encoding/Parser/Internal.hs
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@@ -1,4 +1,5 @@
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{-# LANGUAGE LambdaCase #-}
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+{-# LANGUAGE CPP #-}
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-- | Definition of the parsing monad, plus internal
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-- unsafe functions.
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module Data.ProtoLens.Encoding.Parser.Internal
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@@ -36,8 +37,11 @@ instance Applicative Parser where
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(<*>) = ap
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instance Monad Parser where
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- fail s = Parser $ \_ _ -> return $ ParseFailure s
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return = pure
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Parser f >>= g = Parser $ \end pos -> f end pos >>= \case
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ParseSuccess pos' x -> unParser (g x) end pos'
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ParseFailure s -> return $ ParseFailure s
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+#if MIN_VERSION_base(4,13,0)
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+instance MonadFail Parser where
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+#endif
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+ fail s = Parser $ \_ _ -> return $ ParseFailure s
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