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Files
fp-go/internal/optiont/option.go
Dr. Carsten Leue 1713de0c3e fix: introduce stateless iterator
Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com>
2023-07-24 16:43:07 +02:00

81 lines
2.4 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 optiont
import (
F "github.com/IBM/fp-go/function"
"github.com/IBM/fp-go/internal/apply"
FC "github.com/IBM/fp-go/internal/functor"
O "github.com/IBM/fp-go/option"
)
func Of[A, HKTA any](fof func(O.Option[A]) HKTA, a A) HKTA {
return F.Pipe2(a, O.Of[A], fof)
}
func None[A, HKTA any](fof func(O.Option[A]) HKTA) HKTA {
return F.Pipe1(O.None[A](), fof)
}
func OfF[A, HKTA, HKTEA any](fmap func(HKTA, func(A) O.Option[A]) HKTEA, fa HKTA) HKTEA {
return fmap(fa, O.Of[A])
}
func MonadMap[A, B, HKTFA, HKTFB any](fmap func(HKTFA, func(O.Option[A]) O.Option[B]) HKTFB, fa HKTFA, f func(A) B) HKTFB {
// HKTGA = Either[E, A]
// HKTGB = Either[E, B]
return FC.MonadMap(fmap, O.MonadMap[A, B], fa, f)
}
func MonadChain[A, B, HKTFA, HKTFB any](
fchain func(HKTFA, func(O.Option[A]) HKTFB) HKTFB,
fof func(O.Option[B]) HKTFB,
ma HKTFA,
f func(A) HKTFB) HKTFB {
// dispatch to the even more generic implementation
return fchain(ma, O.Fold(F.Nullary2(O.None[B], fof), f))
}
func MonadAp[A, B, HKTFAB, HKTFGAB, HKTFA, HKTFB any](
fap func(HKTFGAB, HKTFA) HKTFB,
fmap func(HKTFAB, func(O.Option[func(A) B]) func(O.Option[A]) O.Option[B]) HKTFGAB,
fab HKTFAB,
fa HKTFA) HKTFB {
// HKTGA = O.Option[A]
// HKTGB = O.Option[B]
// HKTGAB = O.Option[func(a A) B]
return apply.MonadAp(fap, fmap, O.MonadAp[B, A], fab, fa)
}
func MatchE[A, HKTEA, HKTB any](mchain func(HKTEA, func(O.Option[A]) HKTB) HKTB, onNone func() HKTB, onSome func(A) HKTB) func(HKTEA) HKTB {
return F.Bind2nd(mchain, O.Fold(onNone, onSome))
}
func FromOptionK[A, B, HKTB any](
fof func(O.Option[B]) HKTB,
f func(A) O.Option[B]) func(A) HKTB {
return F.Flow2(f, fof)
}
func MonadChainOptionK[A, B, HKTA, HKTB any](
fchain func(HKTA, func(O.Option[A]) HKTB) HKTB,
fof func(O.Option[B]) HKTB,
ma HKTA,
f func(A) O.Option[B],
) HKTB {
return MonadChain(fchain, fof, ma, FromOptionK(fof, f))
}