mirror of
https://github.com/IBM/fp-go.git
synced 2025-07-03 00:47:05 +02:00
63 lines
1.7 KiB
Go
63 lines
1.7 KiB
Go
// Copyright (c) 2023 IBM Corp.
|
|
// All rights reserved.
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
package generic
|
|
|
|
import (
|
|
F "github.com/IBM/fp-go/function"
|
|
O "github.com/IBM/fp-go/option"
|
|
P "github.com/IBM/fp-go/pair"
|
|
)
|
|
|
|
// addToMap makes a deep copy of a map and adds a value
|
|
func addToMap[A comparable](a A, m map[A]bool) map[A]bool {
|
|
cpy := make(map[A]bool, len(m)+1)
|
|
for k, v := range m {
|
|
cpy[k] = v
|
|
}
|
|
cpy[a] = true
|
|
return cpy
|
|
}
|
|
|
|
func Uniq[AS ~func() O.Option[P.Pair[AS, A]], K comparable, A any](f func(A) K) func(as AS) AS {
|
|
|
|
var recurse func(as AS, mp map[K]bool) AS
|
|
|
|
recurse = func(as AS, mp map[K]bool) AS {
|
|
return F.Nullary2(
|
|
as,
|
|
O.Chain(func(a P.Pair[AS, A]) O.Option[P.Pair[AS, A]] {
|
|
return F.Pipe3(
|
|
P.Tail(a),
|
|
f,
|
|
O.FromPredicate(func(k K) bool {
|
|
_, ok := mp[k]
|
|
return !ok
|
|
}),
|
|
O.Fold(recurse(P.Head(a), mp), func(k K) O.Option[P.Pair[AS, A]] {
|
|
return O.Of(P.MakePair(recurse(P.Head(a), addToMap(k, mp)), P.Tail(a)))
|
|
}),
|
|
)
|
|
}),
|
|
)
|
|
}
|
|
|
|
return F.Bind2nd(recurse, make(map[K]bool, 0))
|
|
}
|
|
|
|
func StrictUniq[AS ~func() O.Option[P.Pair[AS, A]], A comparable](as AS) AS {
|
|
return Uniq[AS](F.Identity[A])(as)
|
|
}
|