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65 lines
1.8 KiB
Go
65 lines
1.8 KiB
Go
// Copyright (c) 2023 - 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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"log"
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F "github.com/IBM/fp-go/v2/function"
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L "github.com/IBM/fp-go/v2/logging"
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)
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func _log[E, A any](left func(string, ...any), right func(string, ...any), prefix string) Operator[E, A, A] {
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return Fold(
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func(e E) Either[E, A] {
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left("%s: %v", prefix, e)
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return Left[A](e)
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},
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func(a A) Either[E, A] {
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right("%s: %v", prefix, a)
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return Right[E](a)
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})
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}
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// Logger creates a logging function for Either values that logs both Left and Right cases.
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// The function logs the value and then returns the original Either unchanged.
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//
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// Parameters:
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// - loggers: Optional log.Logger instances. If none provided, uses default logger.
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//
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// Example:
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//
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// logger := either.Logger[error, int]()
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// result := F.Pipe2(
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// either.Right[error](42),
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// logger("Processing"),
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// either.Map(N.Mul(2)),
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// )
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// // Logs: "Processing: 42"
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// // result is Right(84)
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func Logger[E, A any](loggers ...*log.Logger) func(string) Operator[E, A, A] {
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left, right := L.LoggingCallbacks(loggers...)
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return func(prefix string) Operator[E, A, A] {
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delegate := _log[E, A](left, right, prefix)
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return func(ma Either[E, A]) Either[E, A] {
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return F.Pipe1(
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delegate(ma),
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ChainTo[A](ma),
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)
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}
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}
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}
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