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18 lines
262 B
Idris
18 lines
262 B
Idris
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module List
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data List a = Nil | (::) a (List a)
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infixr 5 ::
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infixr 5 ++
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interface Monoid ty where
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neutral : ty
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(++) : ty -> ty -> ty
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Monoid (List a) where
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neutral = []
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xs ++ ys = case xs of
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[] => ys
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(x :: xs) => let ih = xs ++ ys in x :: ih
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