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Implement v2 using type aliases (#141)
* fix: initial checkin of v2 Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: slowly migrate IO Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: migrate MonadTraverseArray and TraverseArray Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: migrate traversal Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: complete migration of IO Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: migrate ioeither Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: refactorY Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: next step in migration Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: adjust IO generation code Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: get rid of more IO methods Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: get rid of more IO * fix: convert iooption Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: convert reader Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: convert a bit of reader Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: new build script Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: cleanup Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: reformat Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: simplify Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: some cleanup Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: adjust Pair to Haskell semantic Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: documentation and testcases Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: some performance optimizations Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: remove coverage Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> * fix: better doc Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com> --------- Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com>
This commit is contained in:
Carsten Leue
GitHub
95
v2/array/sequence.go
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95
v2/array/sequence.go
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// 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 array
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import (
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F "github.com/IBM/fp-go/v2/function"
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O "github.com/IBM/fp-go/v2/option"
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)
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// Sequence takes an array where elements are HKT<A> (higher kinded type) and,
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// using an applicative of that HKT, returns an HKT of []A.
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//
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// For example, it can turn:
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// - []Either[error, string] into Either[error, []string]
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// - []Option[int] into Option[[]int]
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//
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// Sequence requires an Applicative of the HKT you are targeting. To turn an
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// []Either[E, A] into an Either[E, []A], it needs an Applicative for Either.
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// To turn an []Option[A] into an Option[[]A], it needs an Applicative for Option.
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//
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// Note: We need to pass the members of the applicative explicitly because Go does not
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// support higher kinded types or template methods on structs or interfaces.
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//
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// Type parameters:
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// - HKTA = HKT<A> (e.g., Option[A], Either[E, A])
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// - HKTRA = HKT<[]A> (e.g., Option[[]A], Either[E, []A])
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// - HKTFRA = HKT<func(A)[]A> (e.g., Option[func(A)[]A])
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//
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// Example:
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//
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// import "github.com/IBM/fp-go/v2/option"
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//
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// opts := []option.Option[int]{
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// option.Some(1),
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// option.Some(2),
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// option.Some(3),
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// }
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//
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// seq := array.Sequence(
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// option.Of[[]int],
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// option.MonadMap[[]int, func(int) []int],
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// option.MonadAp[[]int, int],
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// )
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// result := seq(opts) // Some([1, 2, 3])
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func Sequence[A, HKTA, HKTRA, HKTFRA any](
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_of func([]A) HKTRA,
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_map func(HKTRA, func([]A) func(A) []A) HKTFRA,
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_ap func(HKTFRA, HKTA) HKTRA,
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) func([]HKTA) HKTRA {
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ca := F.Curry2(Append[A])
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empty := _of(Empty[A]())
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return Reduce(func(fas HKTRA, fa HKTA) HKTRA {
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return _ap(_map(fas, ca), fa)
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}, empty)
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}
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// ArrayOption returns a function to convert a sequence of options into an option of a sequence.
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// If all options are Some, returns Some containing an array of all values.
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// If any option is None, returns None.
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//
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// Example:
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//
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// opts := []option.Option[int]{
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// option.Some(1),
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// option.Some(2),
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// option.Some(3),
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// }
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// result := array.ArrayOption[int]()(opts) // Some([1, 2, 3])
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//
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// opts2 := []option.Option[int]{
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// option.Some(1),
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// option.None[int](),
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// option.Some(3),
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// }
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// result2 := array.ArrayOption[int]()(opts2) // None
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func ArrayOption[A any]() func([]O.Option[A]) O.Option[[]A] {
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return Sequence(
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O.Of[[]A],
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O.MonadMap[[]A, func(A) []A],
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O.MonadAp[[]A, A],
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)
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}
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