// Copyright (c) 2024 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 pair

import (
	EQ "github.com/IBM/fp-go/eq"
)

// Constructs an equal predicate for an `Either`
func Eq[A, B any](a EQ.Eq[A], b EQ.Eq[B]) EQ.Eq[Pair[A, B]] {
	return EQ.FromEquals(func(l, r Pair[A, B]) bool {
		return a.Equals(Head(l), Head(r)) && b.Equals(Tail(l), Tail(r))
	})

}

// FromStrictEquals constructs an [EQ.Eq] from the canonical comparison function
func FromStrictEquals[A, B comparable]() EQ.Eq[Pair[A, B]] {
	return Eq(EQ.FromStrictEquals[A](), EQ.FromStrictEquals[B]())
}