df8bbf5438
Reason: it contains a bunch of little functions that are supposed to be defined in other modules.
42 lines
1.3 KiB
Text
42 lines
1.3 KiB
Text
/-
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Copyright (c) 2016 Microsoft Corporation. All rights reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Authors: Leonardo de Moura, Sebastian Ullrich
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-/
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prelude
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import Init.Control.Functor
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open Function
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universes u v
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class HasPure (f : Type u → Type v) :=
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(pure {} {α : Type u} : α → f α)
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export HasPure (pure)
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class HasSeq (f : Type u → Type v) : Type (max (u+1) v) :=
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(seq : ∀ {α β : Type u}, f (α → β) → f α → f β)
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infixl <*> := HasSeq.seq
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class HasSeqLeft (f : Type u → Type v) : Type (max (u+1) v) :=
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(seqLeft : ∀ {α β : Type u}, f α → f β → f α)
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infixl <* := HasSeqLeft.seqLeft
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class HasSeqRight (f : Type u → Type v) : Type (max (u+1) v) :=
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(seqRight : ∀ {α β : Type u}, f α → f β → f β)
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infixr *> := HasSeqRight.seqRight
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class Applicative (f : Type u → Type v) extends Functor f, HasPure f, HasSeq f, HasSeqLeft f, HasSeqRight f :=
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(map := fun _ _ x y => pure x <*> y)
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(seqLeft := fun α β a b => const β <$> a <*> b)
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(seqRight := fun α β a b => const α id <$> a <*> b)
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@[macroInline]
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def when {m : Type → Type u} [Applicative m] (c : Prop) [h : Decidable c] (t : m Unit) : m Unit :=
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if c then t else pure ()
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@[macroInline]
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def unless {m : Type → Type u} [Applicative m] (c : Prop) [h : Decidable c] (e : m Unit) : m Unit :=
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if c then pure () else e
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