29 lines
770 B
Text
29 lines
770 B
Text
/-
|
||
Copyright (c) 2016 Microsoft Corporation. All rights reserved.
|
||
Released under Apache 2.0 license as described in the file LICENSE.
|
||
Authors: Leonardo de Moura
|
||
-/
|
||
prelude
|
||
import Init.Data.UInt
|
||
import Init.Data.String
|
||
universes u
|
||
|
||
class Hashable (α : Type u) :=
|
||
(hash : α → USize)
|
||
|
||
export Hashable (hash)
|
||
|
||
@[extern "lean_usize_mix_hash"]
|
||
constant mixHash (u₁ u₂ : USize) : USize := arbitrary _
|
||
|
||
@[extern "lean_string_hash"]
|
||
protected constant String.hash (s : String) : USize := arbitrary _
|
||
instance : Hashable String := ⟨String.hash⟩
|
||
|
||
protected def Nat.hash (n : Nat) : USize :=
|
||
USize.ofNat n
|
||
|
||
instance : Hashable Nat := ⟨Nat.hash⟩
|
||
|
||
instance {α β} [Hashable α] [Hashable β] : Hashable (α × β) :=
|
||
⟨fun ⟨a, b⟩ => mixHash (hash a) (hash b)⟩
|