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45 lines
1.3 KiB
Go
45 lines
1.3 KiB
Go
// Copyright (c) 2023 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 iso
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import (
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F "github.com/IBM/fp-go/function"
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I "github.com/IBM/fp-go/optics/iso"
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IL "github.com/IBM/fp-go/optics/iso/lens"
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L "github.com/IBM/fp-go/optics/lens"
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O "github.com/IBM/fp-go/option"
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)
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// FromNillable converts a nillable value to an option and back
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func FromNillable[T any]() I.Iso[*T, O.Option[T]] {
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return I.MakeIso(F.Flow2(
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O.FromPredicate(F.IsNonNil[T]),
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O.Map(F.Deref[T]),
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),
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O.Fold(F.Constant((*T)(nil)), F.Ref[T]),
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)
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}
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// Compose converts a Lens to a property of `A` into a lens to a property of type `B`
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// the transformation is done via an ISO
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func Compose[S, A, B any](ab I.Iso[A, B]) func(sa L.Lens[S, A]) L.Lens[S, B] {
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return F.Pipe2(
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ab,
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IL.IsoAsLens[A, B],
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L.Compose[S, A, B],
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)
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}
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