26 lines
No EOL
546 B
Elm
26 lines
No EOL
546 B
Elm
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module Either where
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import List (filter, partition)
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data Either a b = Left a | Right b
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either : (a -> c) -> (b -> c) -> Either a b -> c
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either f g e = case e of { Left x -> f x ; Right y -> g y }
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isLeft : Either a b -> Bool
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isLeft e = case e of { Left _ -> True ; _ -> False }
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isRight : Either a b -> Bool
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isRight e = case e of { Right _ -> True ; _ -> False }
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lefts : [Either a b] -> [a]
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lefts = filter isLeft
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rights : [Either a b] -> [b]
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rights = filter isRight
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partition : [Either a b] -> ([a],[b])
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partition = partition isLeft |