lean4-htt/library/Init/Data/HashSet.lean
Leonardo de Moura bf1ea58deb feat: add HashSet
It is just a wrapper for `HashMap`
2019-10-27 11:35:36 -07:00

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/-
Copyright (c) 2019 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
-/
prelude
import Init.Data.HashMap
universes u v
structure HashSet (α : Type u) [HasBeq α] [Hashable α] :=
(set : HashMap α Unit)
def mkHashSet {α : Type u} [HasBeq α] [Hashable α] (nbuckets := 8) : HashSet α :=
{ set := mkHashMap nbuckets }
namespace HashSet
variables {α : Type u} [HasBeq α] [Hashable α]
instance : Inhabited (HashSet α) :=
⟨mkHashSet⟩
instance : HasEmptyc (HashSet α) :=
⟨mkHashSet⟩
@[inline] def insert (s : HashSet α) (a : α) : HashSet α :=
{ set := s.set.insert a () }
@[inline] def erase (s : HashSet α) (a : α) : HashSet α :=
{ set := s.set.erase a }
@[inline] def contains (s : HashSet α) (a : α) : Bool :=
s.set.contains a
@[inline] def size (s : HashSet α) : Nat :=
s.set.size
@[inline] def isEmpty (s : HashSet α) : Bool :=
s.set.isEmpty
@[inline] def empty : HashSet α :=
mkHashSet
@[inline] def mfold {β : Type v} {m : Type v → Type v} [Monad m] (f : β → α → m β) (d : β) (s : HashSet α) : m β :=
s.set.mfold (fun d a _ => f d a) d
@[inline] def fold {β : Type v} (f : β → α → β) (d : β) (s : HashSet α) : β :=
Id.run $ s.mfold f d
end HashSet