mirror of
https://github.com/IBM/fp-go.git
synced 2025-11-23 22:14:53 +02:00
68 lines
2.1 KiB
Go
68 lines
2.1 KiB
Go
// Copyright (c) 2023 - 2025 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/v2/function"
|
|
)
|
|
|
|
// WithResource constructs a function that creates a resource, operates on it, and then releases it.
|
|
// This ensures proper resource cleanup even if operations fail.
|
|
// The resource is released immediately after the operation completes.
|
|
//
|
|
// Parameters:
|
|
// - onCreate: Function to create/acquire the resource
|
|
// - onRelease: Function to release/cleanup the resource
|
|
//
|
|
// Returns a function that takes an operation to perform on the resource.
|
|
//
|
|
// Example:
|
|
//
|
|
// withFile := either.WithResource(
|
|
// func() either.Either[error, *os.File] {
|
|
// return either.TryCatchError(os.Open("file.txt"))
|
|
// },
|
|
// func(f *os.File) either.Either[error, any] {
|
|
// return either.TryCatchError(f.Close())
|
|
// },
|
|
// )
|
|
// result := withFile(func(f *os.File) either.Either[error, string] {
|
|
// // Use file here
|
|
// return either.Right[error]("data")
|
|
// })
|
|
func WithResource[E, R, A, ANY any](onCreate func() Either[E, R], onRelease Kleisli[E, R, 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),
|
|
)
|
|
})
|
|
},
|
|
)
|
|
}
|
|
}
|