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57 lines
1.8 KiB
Go
57 lines
1.8 KiB
Go
// Copyright (c) 2024 - 2025 IBM Corp.
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// All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package either
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import (
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"github.com/IBM/fp-go/v2/internal/monad"
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)
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type eitherMonad[E, A, B any] struct{}
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func (o *eitherMonad[E, A, B]) Of(a A) Either[E, A] {
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return Of[E, A](a)
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}
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func (o *eitherMonad[E, A, B]) Map(f func(A) B) Operator[E, A, B] {
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return Map[E, A, B](f)
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}
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func (o *eitherMonad[E, A, B]) Chain(f func(A) Either[E, B]) Operator[E, A, B] {
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return Chain[E, A, B](f)
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}
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func (o *eitherMonad[E, A, B]) Ap(fa Either[E, A]) Operator[E, func(A) B, B] {
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return Ap[B, E, A](fa)
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}
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// Monad implements the monadic operations for Either.
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// A monad combines the capabilities of Functor (Map), Applicative (Ap), and Chain (flatMap/bind).
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// This allows for sequential composition of computations that may fail.
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//
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// Example:
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//
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// m := either.Monad[error, int, string]()
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// result := m.Chain(func(x int) either.Either[error, string] {
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// if x > 0 {
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// return either.Right[error](strconv.Itoa(x))
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// }
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// return either.Left[string](errors.New("negative"))
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// })(either.Right[error](42))
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// // result is Right("42")
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func Monad[E, A, B any]() monad.Monad[A, B, Either[E, A], Either[E, B], Either[E, func(A) B]] {
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return &eitherMonad[E, A, B]{}
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}
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