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>
2025-11-23 22:14:53 +02:00 · 2025-11-06 09:27:00 +01:00
parent 7874859c4b
commit 3385c705dc
748 changed files with 97722 additions and 24 deletions
--- a/v2/array/traverse.go
+++ b/v2/array/traverse.go
@@ -0,0 +1,78 @@
+// Copyright (c) 2023 - 2025 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 array
+
+import (
+	"github.com/IBM/fp-go/v2/internal/array"
+)
+
+// Traverse maps each element of an array to an effect (HKT), then collects the results
+// into an effect of an array. This is like a combination of Map and Sequence.
+//
+// Unlike Sequence which works with []HKT<A> -> HKT<[]A>, Traverse works with
+// []A -> (A -> HKT<B>) -> HKT<[]B>, allowing you to transform elements while sequencing effects.
+//
+// Type parameters:
+//   - HKTB = HKT<B> (e.g., Option[B], Either[E, B])
+//   - HKTAB = HKT<func(B)[]B> (intermediate type for applicative)
+//   - HKTRB = HKT<[]B> (e.g., Option[[]B], Either[E, []B])
+//
+// Example:
+//
+//	import (
+//	    "github.com/IBM/fp-go/v2/option"
+//	    "strconv"
+//	)
+//
+//	// Parse strings to ints, returning None if any parse fails
+//	parseAll := array.Traverse(
+//	    option.Of[[]int],
+//	    option.Map[[]int, func(int) []int],
+//	    option.Ap[[]int, int],
+//	    func(s string) option.Option[int] {
+//	        if n, err := strconv.Atoi(s); err == nil {
+//	            return option.Some(n)
+//	        }
+//	        return option.None[int]()
+//	    },
+//	)
+//
+//	result := parseAll([]string{"1", "2", "3"}) // Some([1, 2, 3])
+//	result2 := parseAll([]string{"1", "x", "3"}) // None
+func Traverse[A, B, HKTB, HKTAB, HKTRB any](
+	fof func([]B) HKTRB,
+	fmap func(func([]B) func(B) []B) func(HKTRB) HKTAB,
+	fap func(HKTB) func(HKTAB) HKTRB,
+
+	f func(A) HKTB) func([]A) HKTRB {
+	return array.Traverse[[]A](fof, fmap, fap, f)
+}
+
+// MonadTraverse is the monadic version of Traverse that takes the array as a parameter.
+// It maps each element of an array to an effect (HKT), then collects the results
+// into an effect of an array.
+//
+// This is useful when you want to apply the traverse operation directly without currying.
+func MonadTraverse[A, B, HKTB, HKTAB, HKTRB any](
+	fof func([]B) HKTRB,
+	fmap func(func([]B) func(B) []B) func(HKTRB) HKTAB,
+	fap func(HKTB) func(HKTAB) HKTRB,
+
+	ta []A,
+	f func(A) HKTB) HKTRB {
+
+	return array.MonadTraverse(fof, fmap, fap, ta, f)
+}