lean4-htt/src/Lean/Data/PersistentHashSet.lean
Eric Wieser 6d68aab56a
feat: generalize universes in monadic operators for collections (#10224)
This PR generalizes the monadic operations for `HashMap`, `TreeMap`, and
`HashSet` to work for `m : Type u → Type v`.

This upstreams [a workaround from
Aesop](66a992130e/Aesop/Util/Basic.lean (L57-L66)),
and seems to continue a pattern already established in other files, such
as:
```lean
Array.forM.{u, v, w} {α : Type u} {m : Type v → Type w} [Monad m] (f : α → m PUnit) (as : Array α) (start : Nat := 0)
  (stop : Nat := as.size) : m PUnit
```
2025-09-03 07:24:14 +00:00

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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
-/
module
prelude
public import Lean.Data.PersistentHashMap
public section
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 foldM {β : Type v} {m : Type v → Type w} [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 (pure <| f · ·) init
def toList (s : PersistentHashSet α) : List α :=
s.set.toList.map (·.1)
protected def forIn {_ : BEq α} {_ : Hashable α} [Monad m]
(s : PersistentHashSet α) (init : σ) (f : ασ → m (ForInStep σ)) : m σ := do
PersistentHashMap.forIn s.set init fun p s => f p.1 s
instance {_ : BEq α} {_ : Hashable α} : ForIn m (PersistentHashSet α) α where
forIn := PersistentHashSet.forIn
end PersistentHashSet