ed75005422
change the `Hashable` class from taking a hash function of `Type u` to taking a hash function from `Sort u`. This allows to implement `Hashable` for propositions, which in turn is needed for inductives carrying proofs
49 lines
No EOL
1.1 KiB
Text
49 lines
No EOL
1.1 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
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-/
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prelude
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import Init.Data.UInt
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import Init.Data.String
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universes u
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instance : Hashable Nat where
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hash n := USize.ofNat n
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instance [Hashable α] [Hashable β] : Hashable (α × β) where
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hash | (a, b) => mixHash (hash a) (hash b)
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instance : Hashable Bool where
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hash
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| true => 11
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| false => 13
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protected def Option.hash [Hashable α] : Option α → USize
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| none => 11
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| some a => mixHash (hash a) 13
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instance [Hashable α] : Hashable (Option α) where
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hash
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| none => 11
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| some a => mixHash (hash a) 13
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instance [Hashable α] : Hashable (List α) where
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hash as := as.foldl (fun r a => mixHash r (hash a)) 7
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instance : Hashable UInt32 where
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hash n := n.toUSize
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instance : Hashable UInt64 where
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hash n := n.toUSize
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instance : Hashable USize where
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hash n := n
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instance : Hashable Int where
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hash
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| Int.ofNat n => USize.ofNat (2 * n)
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| Int.negSucc n => USize.ofNat (2 * n + 1)
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instance (P : Prop) : Hashable P where
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hash := Function.const P 0 |