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mirror of https://github.com/IBM/fp-go.git synced 2025-06-21 00:19:34 +02:00

Merge pull request #39 from IBM/cleue-implement-compact

fix: add compact methods
This commit is contained in:
Carsten Leue
2023-09-08 22:57:18 +02:00
committed by GitHub
7 changed files with 116 additions and 1 deletions

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@ -44,3 +44,15 @@ func SequenceArrayG[GA ~[]A, GOA ~[]Either[E, A], E, A any](ma GOA) Either[E, GA
func SequenceArray[E, A any](ma []Either[E, A]) Either[E, []A] { func SequenceArray[E, A any](ma []Either[E, A]) Either[E, []A] {
return SequenceArrayG[[]A](ma) return SequenceArrayG[[]A](ma)
} }
// CompactArrayG discards the none values and keeps the some values
func CompactArrayG[A1 ~[]Either[E, A], A2 ~[]A, E, A any](fa A1) A2 {
return RA.Reduce(fa, func(out A2, value Either[E, A]) A2 {
return MonadFold(value, F.Constant1[E](out), F.Bind1st(RA.Append[A2, A], out))
}, make(A2, len(fa)))
}
// CompactArray discards the none values and keeps the some values
func CompactArray[E, A any](fa []Either[E, A]) []A {
return CompactArrayG[[]Either[E, A], []A](fa)
}

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@ -43,3 +43,24 @@ func SequenceRecordG[GA ~map[K]A, GOA ~map[K]Either[E, A], K comparable, E, A an
func SequenceRecord[K comparable, E, A any](ma map[K]Either[E, A]) Either[E, map[K]A] { func SequenceRecord[K comparable, E, A any](ma map[K]Either[E, A]) Either[E, map[K]A] {
return SequenceRecordG[map[K]A](ma) return SequenceRecordG[map[K]A](ma)
} }
func upsertAtReadWrite[M ~map[K]V, K comparable, V any](r M, k K, v V) M {
r[k] = v
return r
}
// CompactRecordG discards the noe values and keeps the some values
func CompactRecordG[M1 ~map[K]Either[E, A], M2 ~map[K]A, K comparable, E, A any](m M1) M2 {
out := make(M2)
onLeft := F.Constant1[E](out)
return RR.ReduceWithIndex(m, func(key K, _ M2, value Either[E, A]) M2 {
return MonadFold(value, onLeft, func(v A) M2 {
return upsertAtReadWrite(out, key, v)
})
}, out)
}
// CompactRecord discards all none values and keeps the somes
func CompactRecord[K comparable, E, A any](m map[K]Either[E, A]) map[K]A {
return CompactRecordG[map[K]Either[E, A], map[K]A](m)
}

37
either/record_test.go Normal file
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@ -0,0 +1,37 @@
// 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 either
import (
"testing"
"github.com/stretchr/testify/assert"
)
func TestCompactRecord(t *testing.T) {
// make the map
m := make(map[string]Either[string, int])
m["foo"] = Left[int]("error")
m["bar"] = Right[string](1)
// compact it
m1 := CompactRecord(m)
// check expected
exp := map[string]int{
"bar": 1,
}
assert.Equal(t, exp, m1)
}

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@ -44,3 +44,15 @@ func SequenceArrayG[GA ~[]A, GOA ~[]Option[A], A any](ma GOA) Option[GA] {
func SequenceArray[A any](ma []Option[A]) Option[[]A] { func SequenceArray[A any](ma []Option[A]) Option[[]A] {
return SequenceArrayG[[]A](ma) return SequenceArrayG[[]A](ma)
} }
// CompactArrayG discards the none values and keeps the some values
func CompactArrayG[A1 ~[]Option[A], A2 ~[]A, A any](fa A1) A2 {
return RA.Reduce(fa, func(out A2, value Option[A]) A2 {
return MonadFold(value, F.Constant(out), F.Bind1st(RA.Append[A2, A], out))
}, make(A2, len(fa)))
}
// CompactArray discards the none values and keeps the some values
func CompactArray[A any](fa []Option[A]) []A {
return CompactArrayG[[]Option[A], []A](fa)
}

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@ -44,3 +44,21 @@ func SequenceRecordG[GA ~map[K]A, GOA ~map[K]Option[A], K comparable, A any](ma
func SequenceRecord[K comparable, A any](ma map[K]Option[A]) Option[map[K]A] { func SequenceRecord[K comparable, A any](ma map[K]Option[A]) Option[map[K]A] {
return SequenceRecordG[map[K]A](ma) return SequenceRecordG[map[K]A](ma)
} }
func upsertAtReadWrite[M ~map[K]V, K comparable, V any](r M, k K, v V) M {
r[k] = v
return r
}
// CompactRecordG discards the noe values and keeps the some values
func CompactRecordG[M1 ~map[K]Option[A], M2 ~map[K]A, K comparable, A any](m M1) M2 {
bnd := F.Bind12of3(upsertAtReadWrite[M2])
return RR.ReduceWithIndex(m, func(key K, m M2, value Option[A]) M2 {
return MonadFold(value, F.Constant(m), bnd(m, key))
}, make(M2))
}
// CompactRecord discards the noe values and keeps the some values
func CompactRecord[K comparable, A any](m map[K]Option[A]) map[K]A {
return CompactRecordG[map[K]Option[A], map[K]A](m)
}

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@ -30,3 +30,18 @@ func TestSequenceRecord(t *testing.T) {
"b": Of("B"), "b": Of("B"),
})) }))
} }
func TestCompactRecord(t *testing.T) {
// make the map
m := make(map[string]Option[int])
m["foo"] = None[int]()
m["bar"] = Some(1)
// compact it
m1 := CompactRecord(m)
// check expected
exp := map[string]int{
"bar": 1,
}
assert.Equal(t, exp, m1)
}

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@ -23,7 +23,7 @@ import (
O "github.com/IBM/fp-go/option" O "github.com/IBM/fp-go/option"
) )
// AssertLaws asserts the apply monad laws for the `Either` monad // AssertLaws asserts the apply monad laws for the [Option] monad
func AssertLaws[A, B, C any](t *testing.T, func AssertLaws[A, B, C any](t *testing.T,
eqa EQ.Eq[A], eqa EQ.Eq[A],
eqb EQ.Eq[B], eqb EQ.Eq[B],