5884b9c19a
@Kha The fields are not mutually recursive yet, but it is good enough for writing examples in the manual. See new test
23 lines
534 B
Text
23 lines
534 B
Text
namespace Exp
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universes u v w
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def StateT' (σ : Type u) (m : Type u → Type v) (α : Type u) : Type (max u v) :=
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σ → m (α × σ)
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instance [Monad m] : Monad (StateT' σ m) where
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pure a := fun s => pure (a, s)
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bind x f := fun s => do
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let (a, s) ← x s
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f a s
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map f x := fun s => do
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let (a, s) ← x s
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pure (f a, s)
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instance [ToString α] [ToString β] : ToString (Sum α β) where
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toString : Sum α β → String
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| Sum.inr a => "inl" ++ toString a
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| Sum.inl b => "inr" ++ toString b
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end Exp
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