d34386fef7
We can now elaborate https://gist.github.com/gebner/439273deee592603190d4f8b4447295b in 1.6 secs and using less than 500Kb of stack space. It was takins 44 secs and 5Mb before this commit. Two modifications: 1) Use pre_monad.seq instead of pre_monad.and_then. They have the same implementation, but seq is not marked as [inline]. 2) Modify how we concatenate the tactics in a begin...end block. Before: (((a_1 ++ a_2) ++ a_3) ++ a_4) After: ((a_1 ++ a_2) ++ (a_3 ++ a_4))
38 lines
1.3 KiB
Text
38 lines
1.3 KiB
Text
/-
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Copyright (c) Luke Nelson and Jared Roesch. All rights reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Authors: Luke Nelson and Jared Roesch
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-/
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prelude
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import init.category.applicative
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universe variables u v
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class pre_monad (m : Type u → Type v) :=
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(bind : Π {a b : Type u}, m a → (a → m b) → m b)
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@[inline] def bind {m : Type u → Type v} [pre_monad m] {a b : Type u} : m a → (a → m b) → m b :=
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pre_monad.bind
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@[inline] def pre_monad.and_then {a b : Type u} {m : Type u → Type v} [pre_monad m] (x : m a) (y : m b) : m b :=
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do x, y
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class monad (m : Type u → Type v) extends functor m, pre_monad m : Type (max u+1 v) :=
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(ret : Π {a : Type u}, a → m a)
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@[inline] def return {m : Type u → Type v} [monad m] {a : Type u} : a → m a :=
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monad.ret m
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def fapp {m : Type u → Type v} [monad m] {a b : Type u} (f : m (a → b)) (a : m a) : m b :=
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do g ← f,
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b ← a,
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return (g b)
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@[inline] instance monad_is_applicative (m : Type u → Type v) [monad m] : applicative m :=
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⟨@fmap _ _, @return _ _, @fapp _ _⟩
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infixl ` >>= `:2 := bind
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infixl ` >> `:2 := pre_monad.and_then
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/- Identical to pre_monad.and_then, but it is not inlined. -/
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def pre_monad.seq {a b : Type u} {m : Type u → Type v} [pre_monad m] (x : m a) (y : m b) : m b :=
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do x, y
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