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fp-go/io/generic/ap.go
Dr. Carsten Leue 7476b70a23 fix: add optics and consistent copyright
Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com>
2023-07-23 22:05:54 +02:00

97 lines
3.0 KiB
Go

// 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 generic
import (
G "github.com/IBM/fp-go/internal/apply"
)
const (
// useParallel is the feature flag to control if we use the parallel or the sequential implementation of ap
useParallel = true
)
// MonadApSeq implements the applicative on a single thread by first executing mab and the ma
func MonadApSeq[GA ~func() A, GB ~func() B, GAB ~func() func(A) B, A, B any](mab GAB, ma GA) GB {
return MakeIO[GB](func() B {
return mab()(ma())
})
}
// MonadApPar implements the applicative on two threads, the main thread executes mab and the actuall
// apply operation and the second thred computes ma. Communication between the threads happens via a channel
func MonadApPar[GA ~func() A, GB ~func() B, GAB ~func() func(A) B, A, B any](mab GAB, ma GA) GB {
return MakeIO[GB](func() B {
c := make(chan A)
go func() {
c <- ma()
close(c)
}()
return mab()(<-c)
})
}
// MonadAp implements the `ap` operation. Depending on a feature flag this will be sequential or parallel, the preferred implementation
// is parallel
func MonadAp[GA ~func() A, GB ~func() B, GAB ~func() func(A) B, A, B any](mab GAB, ma GA) GB {
if useParallel {
return MonadApPar[GA, GB](mab, ma)
}
return MonadApSeq[GA, GB](mab, ma)
}
// MonadApFirst combines two effectful actions, keeping only the result of the first.
func MonadApFirst[GA ~func() A, GB ~func() B, GBA ~func() func(B) A, A, B any](first GA, second GB) GA {
return G.MonadApFirst(
MonadAp[GB, GA, GBA, B, A],
MonadMap[GA, GBA, A, func(B) A],
first,
second,
)
}
// ApFirst combines two effectful actions, keeping only the result of the first.
func ApFirst[GA ~func() A, GB ~func() B, GBA ~func() func(B) A, A, B any](second GB) func(GA) GA {
return G.ApFirst(
MonadAp[GB, GA, GBA, B, A],
MonadMap[GA, GBA, A, func(B) A],
second,
)
}
// MonadApSecond combines two effectful actions, keeping only the result of the second.
func MonadApSecond[GA ~func() A, GB ~func() B, GBB ~func() func(B) B, A, B any](first GA, second GB) GB {
return G.MonadApSecond(
MonadAp[GB, GB, GBB, B, B],
MonadMap[GA, GBB, A, func(B) B],
first,
second,
)
}
// ApSecond combines two effectful actions, keeping only the result of the second.
func ApSecond[GA ~func() A, GB ~func() B, GBB ~func() func(B) B, A, B any](second GB) func(GA) GB {
return G.ApSecond(
MonadAp[GB, GB, GBB, B, B],
MonadMap[GA, GBB, A, func(B) B],
second,
)
}