lean4-htt/src/Lean/Data/PersistentHashSet.lean
2022-09-26 05:46:04 -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
-/
import Lean.Data.PersistentHashMap
namespace Lean
universe u v
structure PersistentHashSet (α : Type u) [BEq α] [Hashable α] where
(set : PersistentHashMap α Unit)
abbrev PHashSet (α : Type u) [BEq α] [Hashable α] := PersistentHashSet α
namespace PersistentHashSet
@[inline] def empty [BEq α] [Hashable α] : PersistentHashSet α :=
{ set := PersistentHashMap.empty }
instance [BEq α] [Hashable α] : Inhabited (PersistentHashSet α) where
default := empty
instance [BEq α] [Hashable α] : EmptyCollection (PersistentHashSet α) :=
⟨empty⟩
variable {_ : BEq α} {_ : Hashable α}
@[inline] def isEmpty (s : PersistentHashSet α) : Bool :=
s.set.isEmpty
@[inline] def insert (s : PersistentHashSet α) (a : α) : PersistentHashSet α :=
{ set := s.set.insert a () }
@[inline] def erase (s : PersistentHashSet α) (a : α) : PersistentHashSet α :=
{ set := s.set.erase a }
@[inline] def find? (s : PersistentHashSet α) (a : α) : Option α :=
match s.set.findEntry? a with
| some (a, _) => some a
| none => none
@[inline] def contains (s : PersistentHashSet α) (a : α) : Bool :=
s.set.contains a
@[inline] def size (s : PersistentHashSet α) : Nat :=
s.set.size
@[inline] def foldM {β : Type v} {m : Type v → Type v} [Monad m] (f : β → α → m β) (init : β) (s : PersistentHashSet α) : m β :=
s.set.foldlM (init := init) fun d a _ => f d a
@[inline] def fold {β : Type v} (f : β → α → β) (init : β) (s : PersistentHashSet α) : β :=
Id.run $ s.foldM f init