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33 lines
700 B
Plaintext
33 lines
700 B
Plaintext
--map/traverse
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structural ability Noop where
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noop : a -> {Noop} a
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structural ability Noop2 where
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noop2 : a -> a -> {Noop2} a
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structural type List a = Nil | Cons a (List a)
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map : (a -> b) -> List a -> List b
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map f = cases
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List.Nil -> List.Nil
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List.Cons h t -> List.Cons (f h) (map f t)
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c = List.Cons
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z : ∀ a . List a
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z = List.Nil
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ex = (c 1 (c 2 (c 3 z)))
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pureMap : List Text
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pureMap = map (a -> "hello") ex
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-- `map` is ability polymorphic
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zappy : '{Noop} (List Nat)
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zappy = 'let map (zap -> Noop.noop (zap Nat.+ 1)) ex
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-- mixing multiple abilitys in a call to `map` works fine
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zappy2 : '{Noop, Noop2} (List Nat)
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zappy2 = 'let
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map (zap -> Noop.noop (zap Nat.+ Noop2.noop2 2 7)) ex
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