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37 lines
752 B
Idris
37 lines
752 B
Idris
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module AppComp
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import Control.Monad.Error.Either
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import Control.Monad.Identity
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-- Errorful monadic functions --
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f1 : Monad m => Int -> m (Either String Int)
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f1 5 = pure $ Right 0
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f1 _ = pure $ Left "fail 1"
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f2 : Monad m => Int -> m (Either String Int)
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f2 6 = pure $ Right 0
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f2 _ = pure $ Left "fail 2"
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-- Compositions --
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c1 : Monad m => m (Either String Int)
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c1 = f1 1 *> f2 1
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c2 : Monad m => m (Either String Int)
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c2 = (f1 1 *> f2 1) @{Applicative.Compose}
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c3 : Monad m => m (Either String Int)
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c3 = runEitherT $ MkEitherT {m} (f1 1) *> MkEitherT {m} (f2 1)
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-- These checks are meant to be true --
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r1 : Bool
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r1 = runIdentity c1 == Left "fail 2"
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r2 : Bool
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r2 = runIdentity c2 == Left "fail 1"
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r3 : Bool
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r3 = runIdentity c3 == Left "fail 1"
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