// 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 either import ( F "github.com/IBM/fp-go/function" ) // constructs a function that creates a resource, then operates on it and then releases the resource func WithResource[E, R, A any](onCreate func() Either[E, R], onRelease func(R) Either[E, any]) func(func(R) Either[E, A]) Either[E, A] { return func(f func(R) Either[E, A]) Either[E, A] { return MonadChain( onCreate(), func(r R) Either[E, A] { // run the code and make sure to release as quickly as possible res := f(r) released := onRelease(r) // handle the errors return MonadFold( res, Left[A, E], func(a A) Either[E, A] { return F.Pipe1( released, MapTo[E, any](a), ) }) }, ) } }