Merge pull request #62 from IBM/cleue-add-missing-chain-readeriok

fix: add missing ChainReaderIOK

.github/workflows/build.yml

@@ -29,7 +29,7 @@ jobs:
         go-version: [ '1.20.x', '1.21.x' ]
     steps:
       # full checkout for semantic-release
-      - uses: actions/checkout@c85c95e3d7251135ab7dc9ce3241c5835cc595a9 # v3.5.3
+      - uses: actions/checkout@8ade135a41bc03ea155e62e844d188df1ea18608 # v4.1.0
         with:
           fetch-depth: 0
       - name: Set up go ${{ matrix.go-version }}
@@ -55,7 +55,7 @@ jobs:
     steps:
       # full checkout for semantic-release
       - name: Full checkout
-        uses: actions/checkout@c85c95e3d7251135ab7dc9ce3241c5835cc595a9 # v3.5.3
+        uses: actions/checkout@8ade135a41bc03ea155e62e844d188df1ea18608 # v4.1.0
         with:
           fetch-depth: 0
 

array/array.go

@@ -308,3 +308,11 @@ func Fold[A any](m M.Monoid[A]) func([]A) A {
 func Push[A any](a A) func([]A) []A {
 	return G.Push[[]A](a)
 }
+
+func MonadFlap[A, B any](fab []func(A) B, a A) []B {
+	return G.MonadFlap[func(A) B, []func(A) B, []B, A, B](fab, a)
+}
+
+func Flap[A, B any](a A) func([]func(A) B) []B {
+	return G.Flap[func(A) B, []func(A) B, []B, A, B](a)
+}

array/generic/array.go

@@ -18,6 +18,7 @@ package generic
 import (
 	F "github.com/IBM/fp-go/function"
 	"github.com/IBM/fp-go/internal/array"
+	FC "github.com/IBM/fp-go/internal/functor"
 	M "github.com/IBM/fp-go/monoid"
 	O "github.com/IBM/fp-go/option"
 	"github.com/IBM/fp-go/tuple"
@@ -250,3 +251,11 @@ func Fold[AS ~[]A, A any](m M.Monoid[A]) func(AS) A {
 func Push[GA ~[]A, A any](a A) func(GA) GA {
 	return F.Bind2nd(array.Push[GA, A], a)
 }
+
+func MonadFlap[FAB ~func(A) B, GFAB ~[]FAB, GB ~[]B, A, B any](fab GFAB, a A) GB {
+	return FC.MonadFlap(MonadMap[GFAB, GB], fab, a)
+}
+
+func Flap[FAB ~func(A) B, GFAB ~[]FAB, GB ~[]B, A, B any](a A) func(GFAB) GB {
+	return F.Bind2nd(MonadFlap[FAB, GFAB, GB, A, B], a)
+}

array/nonempty/array.go

@@ -0,0 +1,124 @@
+// 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 nonempty
+
+import (
+	G "github.com/IBM/fp-go/array/generic"
+	F "github.com/IBM/fp-go/function"
+	"github.com/IBM/fp-go/internal/array"
+	S "github.com/IBM/fp-go/semigroup"
+)
+
+// NonEmptyArray represents an array with at least one element
+type NonEmptyArray[A any] []A
+
+// Of constructs a single element array
+func Of[A any](first A) NonEmptyArray[A] {
+	return G.Of[NonEmptyArray[A]](first)
+}
+
+// From constructs a [NonEmptyArray] from a set of variadic arguments
+func From[A any](first A, data ...A) NonEmptyArray[A] {
+	count := len(data)
+	if count == 0 {
+		return Of(first)
+	}
+	// allocate the requested buffer
+	buffer := make(NonEmptyArray[A], count+1)
+	buffer[0] = first
+	copy(buffer[1:], data)
+	return buffer
+}
+
+func IsEmpty[A any](as NonEmptyArray[A]) bool {
+	return false
+}
+
+func IsNonEmpty[A any](as NonEmptyArray[A]) bool {
+	return true
+}
+
+func MonadMap[A, B any](as NonEmptyArray[A], f func(a A) B) NonEmptyArray[B] {
+	return G.MonadMap[NonEmptyArray[A], NonEmptyArray[B]](as, f)
+}
+
+func Map[A, B any](f func(a A) B) func(NonEmptyArray[A]) NonEmptyArray[B] {
+	return F.Bind2nd(MonadMap[A, B], f)
+}
+
+func Reduce[A, B any](f func(B, A) B, initial B) func(NonEmptyArray[A]) B {
+	return func(as NonEmptyArray[A]) B {
+		return array.Reduce(as, f, initial)
+	}
+}
+
+func Tail[A any](as NonEmptyArray[A]) []A {
+	return as[1:]
+}
+
+func Head[A any](as NonEmptyArray[A]) A {
+	return as[0]
+}
+
+func First[A any](as NonEmptyArray[A]) A {
+	return as[0]
+}
+
+func Last[A any](as NonEmptyArray[A]) A {
+	return as[len(as)-1]
+}
+
+func Size[A any](as NonEmptyArray[A]) int {
+	return G.Size(as)
+}
+
+func Flatten[A any](mma NonEmptyArray[NonEmptyArray[A]]) NonEmptyArray[A] {
+	return G.Flatten(mma)
+}
+
+func MonadChain[A, B any](fa NonEmptyArray[A], f func(a A) NonEmptyArray[B]) NonEmptyArray[B] {
+	return G.MonadChain[NonEmptyArray[A], NonEmptyArray[B]](fa, f)
+}
+
+func Chain[A, B any](f func(A) NonEmptyArray[B]) func(NonEmptyArray[A]) NonEmptyArray[B] {
+	return G.Chain[NonEmptyArray[A], NonEmptyArray[B]](f)
+}
+
+func MonadAp[B, A any](fab NonEmptyArray[func(A) B], fa NonEmptyArray[A]) NonEmptyArray[B] {
+	return G.MonadAp[NonEmptyArray[B]](fab, fa)
+}
+
+func Ap[B, A any](fa NonEmptyArray[A]) func(NonEmptyArray[func(A) B]) NonEmptyArray[B] {
+	return G.Ap[NonEmptyArray[B], NonEmptyArray[func(A) B]](fa)
+}
+
+// FoldMap maps and folds a [NonEmptyArray]. Map the [NonEmptyArray] passing each value to the iterating function. Then fold the results using the provided [Semigroup].
+func FoldMap[A, B any](s S.Semigroup[B]) func(func(A) B) func(NonEmptyArray[A]) B {
+	return func(f func(A) B) func(NonEmptyArray[A]) B {
+		return func(as NonEmptyArray[A]) B {
+			return array.Reduce(Tail(as), func(cur B, a A) B {
+				return s.Concat(cur, f(a))
+			}, f(Head(as)))
+		}
+	}
+}
+
+// Fold folds the [NonEmptyArray] using the provided [Semigroup].
+func Fold[A any](s S.Semigroup[A]) func(NonEmptyArray[A]) A {
+	return func(as NonEmptyArray[A]) A {
+		return array.Reduce(Tail(as), s.Concat, Head(as))
+	}
+}

context/readerio/reader.go

@@ -18,6 +18,7 @@ package readerio
 import (
 	"context"
 
+	IO "github.com/IBM/fp-go/io"
 	L "github.com/IBM/fp-go/lazy"
 	R "github.com/IBM/fp-go/readerio/generic"
 )
@@ -38,6 +39,22 @@ func Chain[A, B any](f func(A) ReaderIO[B]) func(ReaderIO[A]) ReaderIO[B] {
 	return R.Chain[ReaderIO[A]](f)
 }
 
+func MonadChainIOK[A, B any](fa ReaderIO[A], f func(A) IO.IO[B]) ReaderIO[B] {
+	return R.MonadChainIOK[ReaderIO[A], ReaderIO[B]](fa, f)
+}
+
+func ChainIOK[A, B any](f func(A) IO.IO[B]) func(ReaderIO[A]) ReaderIO[B] {
+	return R.ChainIOK[ReaderIO[A], ReaderIO[B]](f)
+}
+
+func MonadChainFirstIOK[A, B any](fa ReaderIO[A], f func(A) IO.IO[B]) ReaderIO[A] {
+	return R.MonadChainFirstIOK[ReaderIO[A], ReaderIO[B]](fa, f)
+}
+
+func ChainFirstIOK[A, B any](f func(A) IO.IO[B]) func(ReaderIO[A]) ReaderIO[A] {
+	return R.ChainFirstIOK[ReaderIO[A], ReaderIO[B]](f)
+}
+
 func Of[A any](a A) ReaderIO[A] {
 	return R.Of[ReaderIO[A]](a)
 }

context/readerioeither/generic/reader.go

@@ -480,6 +480,34 @@ func ChainIOK[
 	return RIE.ChainIOK[GRA, GRB](f)
 }
 
+func MonadChainReaderIOK[
+	GRB ~func(context.Context) GIOB,
+	GRA ~func(context.Context) GIOA,
+	GRIO ~func(context.Context) GIO,
+
+	GIOA ~func() E.Either[error, A],
+	GIOB ~func() E.Either[error, B],
+
+	GIO ~func() B,
+
+	A, B any](ma GRA, f func(A) GRIO) GRB {
+	return RIE.MonadChainReaderIOK[GRA, GRB](ma, f)
+}
+
+func ChainReaderIOK[
+	GRB ~func(context.Context) GIOB,
+	GRA ~func(context.Context) GIOA,
+	GRIO ~func(context.Context) GIO,
+
+	GIOA ~func() E.Either[error, A],
+	GIOB ~func() E.Either[error, B],
+
+	GIO ~func() B,
+
+	A, B any](f func(A) GRIO) func(ma GRA) GRB {
+	return RIE.ChainReaderIOK[GRA, GRB](f)
+}
+
 func MonadChainFirstIOK[
 	GRA ~func(context.Context) GIOA,
 	GIOA ~func() E.Either[error, A],

context/readerioeither/monoid.go

@@ -17,6 +17,7 @@ package readerioeither
 
 import (
 	G "github.com/IBM/fp-go/context/readerioeither/generic"
+	L "github.com/IBM/fp-go/lazy"
 	M "github.com/IBM/fp-go/monoid"
 )
 
@@ -34,3 +35,22 @@ func ApplicativeMonoidSeq[A any](m M.Monoid[A]) M.Monoid[ReaderIOEither[A]] {
 func ApplicativeMonoidPar[A any](m M.Monoid[A]) M.Monoid[ReaderIOEither[A]] {
 	return G.ApplicativeMonoidPar[ReaderIOEither[A], ReaderIOEither[func(A) A]](m)
 }
+
+// AlternativeMonoid is the alternative [Monoid] for [ReaderIOEither]
+func AlternativeMonoid[A any](m M.Monoid[A]) M.Monoid[ReaderIOEither[A]] {
+	return M.AlternativeMonoid(
+		Of[A],
+		MonadMap[A, func(A) A],
+		MonadAp[A, A],
+		MonadAlt[A],
+		m,
+	)
+}
+
+// AltMonoid is the alternative [Monoid] for an [ReaderIOEither]
+func AltMonoid[A any](zero L.Lazy[ReaderIOEither[A]]) M.Monoid[ReaderIOEither[A]] {
+	return M.AltMonoid(
+		zero,
+		MonadAlt[A],
+	)
+}

context/readerioeither/reader.go

@@ -164,6 +164,14 @@ func Never[A any]() ReaderIOEither[A] {
 	return G.Never[ReaderIOEither[A]]()
 }
 
+func MonadChainReaderIOK[A, B any](ma ReaderIOEither[A], f func(A) RIO.ReaderIO[B]) ReaderIOEither[B] {
+	return G.MonadChainReaderIOK[ReaderIOEither[B], ReaderIOEither[A]](ma, f)
+}
+
+func ChainReaderIOK[A, B any](f func(A) RIO.ReaderIO[B]) func(ma ReaderIOEither[A]) ReaderIOEither[B] {
+	return G.ChainReaderIOK[ReaderIOEither[B], ReaderIOEither[A]](f)
+}
+
 func MonadChainIOK[A, B any](ma ReaderIOEither[A], f func(A) IO.IO[B]) ReaderIOEither[B] {
 	return G.MonadChainIOK[ReaderIOEither[B], ReaderIOEither[A]](ma, f)
 }

either/either.go

@@ -22,6 +22,8 @@ package either
 import (
 	E "github.com/IBM/fp-go/errors"
 	F "github.com/IBM/fp-go/function"
+	FC "github.com/IBM/fp-go/internal/functor"
+	L "github.com/IBM/fp-go/lazy"
 	O "github.com/IBM/fp-go/option"
 )
 
@@ -92,11 +94,11 @@ func MonadChainTo[E, A, B any](ma Either[E, A], mb Either[E, B]) Either[E, B] {
 }
 
 func MonadChainOptionK[A, B, E any](onNone func() E, ma Either[E, A], f func(A) O.Option[B]) Either[E, B] {
-	return MonadChain(ma, F.Flow2(f, FromOption[E, B](onNone)))
+	return MonadChain(ma, F.Flow2(f, FromOption[B](onNone)))
 }
 
 func ChainOptionK[A, B, E any](onNone func() E) func(func(A) O.Option[B]) func(Either[E, A]) Either[E, B] {
-	from := FromOption[E, B](onNone)
+	from := FromOption[B](onNone)
 	return func(f func(A) O.Option[B]) func(Either[E, A]) Either[E, B] {
 		return Chain(F.Flow2(f, from))
 	}
@@ -142,7 +144,7 @@ func Sequence3[E, T1, T2, T3, R any](f func(T1, T2, T3) Either[E, R]) func(Eithe
 	}
 }
 
-func FromOption[E, A any](onNone func() E) func(O.Option[A]) Either[E, A] {
+func FromOption[A, E any](onNone func() E) func(O.Option[A]) Either[E, A] {
 	return O.Fold(F.Nullary2(onNone, Left[A, E]), Right[E, A])
 }
 
@@ -197,11 +199,11 @@ func Reduce[E, A, B any](f func(B, A) B, initial B) func(Either[E, A]) B {
 	)
 }
 
-func AltW[E, E1, A any](that func() Either[E1, A]) func(Either[E, A]) Either[E1, A] {
+func AltW[E, E1, A any](that L.Lazy[Either[E1, A]]) func(Either[E, A]) Either[E1, A] {
 	return Fold(F.Ignore1of1[E](that), Right[E1, A])
 }
 
-func Alt[E, A any](that func() Either[E, A]) func(Either[E, A]) Either[E, A] {
+func Alt[E, A any](that L.Lazy[Either[E, A]]) func(Either[E, A]) Either[E, A] {
 	return AltW[E](that)
 }
 
@@ -245,3 +247,15 @@ func MonadSequence3[E, T1, T2, T3, R any](e1 Either[E, T1], e2 Either[E, T2], e3
 func Swap[E, A any](val Either[E, A]) Either[A, E] {
 	return MonadFold(val, Right[A, E], Left[E, A])
 }
+
+func MonadFlap[E, A, B any](fab Either[E, func(A) B], a A) Either[E, B] {
+	return FC.MonadFlap(MonadMap[E, func(A) B, B], fab, a)
+}
+
+func Flap[E, A, B any](a A) func(Either[E, func(A) B]) Either[E, B] {
+	return F.Bind2nd(MonadFlap[E, A, B], a)
+}
+
+func MonadAlt[E, A any](fa Either[E, A], that L.Lazy[Either[E, A]]) Either[E, A] {
+	return MonadFold(fa, F.Ignore1of1[E](that), Of[E, A])
+}

either/either_test.go

@@ -112,6 +112,6 @@ func TestChainOptionK(t *testing.T) {
 }
 
 func TestFromOption(t *testing.T) {
-	assert.Equal(t, Left[int]("none"), FromOption[string, int](F.Constant("none"))(O.None[int]()))
-	assert.Equal(t, Right[string](1), FromOption[string, int](F.Constant("none"))(O.Some(1)))
+	assert.Equal(t, Left[int]("none"), FromOption[int](F.Constant("none"))(O.None[int]()))
+	assert.Equal(t, Right[string](1), FromOption[int](F.Constant("none"))(O.Some(1)))
 }

either/monoid.go

@@ -0,0 +1,40 @@
+// 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 (
+	L "github.com/IBM/fp-go/lazy"
+	M "github.com/IBM/fp-go/monoid"
+)
+
+// AlternativeMonoid is the alternative [Monoid] for an [Either]
+func AlternativeMonoid[E, A any](m M.Monoid[A]) M.Monoid[Either[E, A]] {
+	return M.AlternativeMonoid(
+		Of[E, A],
+		MonadMap[E, A, func(A) A],
+		MonadAp[A, E, A],
+		MonadAlt[E, A],
+		m,
+	)
+}
+
+// AltMonoid is the alternative [Monoid] for an [Either]
+func AltMonoid[E, A any](zero L.Lazy[Either[E, A]]) M.Monoid[Either[E, A]] {
+	return M.AltMonoid(
+		zero,
+		MonadAlt[E, A],
+	)
+}

either/semigroup.go

@@ -0,0 +1,27 @@
+// 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 (
+	S "github.com/IBM/fp-go/semigroup"
+)
+
+// AltSemigroup is the alternative [Semigroup] for an [Either]
+func AltSemigroup[E, A any]() S.Semigroup[Either[E, A]] {
+	return S.AltSemigroup(
+		MonadAlt[E, A],
+	)
+}

http/utils.go

@@ -57,7 +57,7 @@ var (
 			GetHeader,
 			R.Lookup[H.Header](HeaderContentType),
 			O.Chain(A.First[string]),
-			E.FromOption[error, string](errors.OnNone("unable to access the [%s] header", HeaderContentType)),
+			E.FromOption[string](errors.OnNone("unable to access the [%s] header", HeaderContentType)),
 			E.ChainFirst(validateJsonContentTypeString),
 		)))
 )

identity/generic/identity.go

@@ -18,6 +18,7 @@ package generic
 import (
 	F "github.com/IBM/fp-go/function"
 	C "github.com/IBM/fp-go/internal/chain"
+	FC "github.com/IBM/fp-go/internal/functor"
 )
 
 func MonadAp[GAB ~func(A) B, B, A any](fab GAB, fa A) B {
@@ -51,3 +52,11 @@ func MonadChainFirst[GAB ~func(A) B, A, B any](fa A, f GAB) A {
 func ChainFirst[GAB ~func(A) B, A, B any](f GAB) func(A) A {
 	return C.ChainFirst(MonadChain[func(A) A, A, A], MonadMap[func(B) A, B, A], f)
 }
+
+func MonadFlap[GAB ~func(A) B, A, B any](fab GAB, a A) B {
+	return FC.MonadFlap(MonadMap[func(GAB) B, GAB, B], fab, a)
+}
+
+func Flap[GAB ~func(A) B, A, B any](a A) func(GAB) B {
+	return F.Bind2nd(MonadFlap[GAB, A, B], a)
+}

identity/identity.go

@@ -63,3 +63,11 @@ func MonadChainFirst[A, B any](fa A, f func(A) B) A {
 func ChainFirst[A, B any](f func(A) B) func(A) A {
 	return G.ChainFirst(f)
 }
+
+func MonadFlap[A, B any](fab func(A) B, a A) B {
+	return G.MonadFlap[func(A) B](fab, a)
+}
+
+func Flap[A, B any](a A) func(func(A) B) B {
+	return G.Flap[func(A) B](a)
+}

internal/fromeither/either.go

@@ -22,8 +22,8 @@ import (
 	O "github.com/IBM/fp-go/option"
 )
 
-func FromOption[E, A, HKTEA any](fromEither func(ET.Either[E, A]) HKTEA, onNone func() E) func(ma O.Option[A]) HKTEA {
-	return F.Flow2(ET.FromOption[E, A](onNone), fromEither)
+func FromOption[A, HKTEA, E any](fromEither func(ET.Either[E, A]) HKTEA, onNone func() E) func(ma O.Option[A]) HKTEA {
+	return F.Flow2(ET.FromOption[A](onNone), fromEither)
 }
 
 func FromPredicate[E, A, HKTEA any](fromEither func(ET.Either[E, A]) HKTEA, pred func(A) bool, onFalse func(A) E) func(A) HKTEA {
@@ -45,7 +45,7 @@ func MonadFromOption[E, A, HKTEA any](
 	)
 }
 
-func FromOptionK[E, A, B, HKTEB any](
+func FromOptionK[A, E, B, HKTEB any](
 	fromEither func(ET.Either[E, B]) HKTEB,
 	onNone func() E) func(f func(A) O.Option[B]) func(A) HKTEB {
 	// helper
@@ -65,7 +65,7 @@ func ChainOptionK[A, E, B, HKTEA, HKTEB any](
 	fromEither func(ET.Either[E, B]) HKTEB,
 	onNone func() E,
 ) func(f func(A) O.Option[B]) func(ma HKTEA) HKTEB {
-	return F.Flow2(FromOptionK[E, A](fromEither, onNone), F.Bind1st(F.Bind2nd[HKTEA, func(A) HKTEB, HKTEB], mchain))
+	return F.Flow2(FromOptionK[A](fromEither, onNone), F.Bind1st(F.Bind2nd[HKTEA, func(A) HKTEB, HKTEB], mchain))
 }
 
 func MonadChainFirstEitherK[A, E, B, HKTEA, HKTEB any](

internal/functor/flap.go

@@ -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 functor
+
+func MonadFlap[FAB ~func(A) B, A, B, HKTFAB, HKTB any](
+	fmap func(HKTFAB, func(FAB) B) HKTB,
+
+	fab HKTFAB,
+	a A,
+) HKTB {
+	return fmap(fab, func(f FAB) B {
+		return f(a)
+	})
+}
+
+func Flap[FAB ~func(A) B, A, B, HKTFAB, HKTB any](
+	fmap func(HKTFAB, func(FAB) B) HKTB,
+
+	a A,
+) func(HKTFAB) HKTB {
+	return func(fab HKTFAB) HKTB {
+		return MonadFlap(fmap, fab, a)
+	}
+}

io/generic/io.go

@@ -20,6 +20,7 @@ import (
 
 	F "github.com/IBM/fp-go/function"
 	C "github.com/IBM/fp-go/internal/chain"
+	FC "github.com/IBM/fp-go/internal/functor"
 	L "github.com/IBM/fp-go/internal/lazy"
 )
 
@@ -143,3 +144,11 @@ func Defer[GA ~func() A, A any](gen func() GA) GA {
 		return gen()()
 	})
 }
+
+func MonadFlap[FAB ~func(A) B, GFAB ~func() FAB, GB ~func() B, A, B any](fab GFAB, a A) GB {
+	return FC.MonadFlap(MonadMap[GFAB, GB, FAB, B], fab, a)
+}
+
+func Flap[FAB ~func(A) B, GFAB ~func() FAB, GB ~func() B, A, B any](a A) func(GFAB) GB {
+	return F.Bind2nd(MonadFlap[FAB, GFAB, GB, A, B], a)
+}

io/io.go

@@ -138,3 +138,11 @@ var Now = G.Now[IO[time.Time]]()
 func Defer[A any](gen func() IO[A]) IO[A] {
 	return G.Defer[IO[A]](gen)
 }
+
+func MonadFlap[A, B any](fab IO[func(A) B], a A) IO[B] {
+	return G.MonadFlap[func(A) B, IO[func(A) B], IO[B], A, B](fab, a)
+}
+
+func Flap[FAB ~func(A) B, GFAB ~func() FAB, GB ~func() B, A, B any](a A) func(IO[func(A) B]) IO[B] {
+	return G.Flap[func(A) B, IO[func(A) B], IO[B], A, B](a)
+}

monoid/alt.go

@@ -19,13 +19,13 @@ import (
 	S "github.com/IBM/fp-go/semigroup"
 )
 
-func AlternativeMonoid[A, HKTA, HKTFA any](
+func AlternativeMonoid[A, HKTA, HKTFA any, LAZYHKTA ~func() HKTA](
 	fof func(A) HKTA,
 
 	fmap func(HKTA, func(A) func(A) A) HKTFA,
 	fap func(HKTFA, HKTA) HKTA,
 
-	falt func(HKTA, func() HKTA) HKTA,
+	falt func(HKTA, LAZYHKTA) HKTA,
 
 	m Monoid[A],
 
@@ -45,9 +45,9 @@ func AlternativeMonoid[A, HKTA, HKTFA any](
 	)
 }
 
-func AltMonoid[HKTA any](
-	fzero func() HKTA,
-	falt func(HKTA, func() HKTA) HKTA,
+func AltMonoid[HKTA any, LAZYHKTA ~func() HKTA](
+	fzero LAZYHKTA,
+	falt func(HKTA, LAZYHKTA) HKTA,
 
 ) Monoid[HKTA] {
 

option/monoid.go

@@ -51,3 +51,22 @@ func Monoid[A any]() func(S.Semigroup[A]) M.Monoid[Option[A]] {
 		return M.MakeMonoid(sg(s).Concat, None[A]())
 	}
 }
+
+// AlternativeMonoid is the alternative [Monoid] for an [Option]
+func AlternativeMonoid[A any](m M.Monoid[A]) M.Monoid[Option[A]] {
+	return M.AlternativeMonoid(
+		Of[A],
+		MonadMap[A, func(A) A],
+		MonadAp[A, A],
+		MonadAlt[A],
+		m,
+	)
+}
+
+// AltMonoid is the alternative [Monoid] for an [Option]
+func AltMonoid[A any]() M.Monoid[Option[A]] {
+	return M.AltMonoid(
+		None[A],
+		MonadAlt[A],
+	)
+}

option/option.go

@@ -18,6 +18,7 @@ package option
 
 import (
 	F "github.com/IBM/fp-go/function"
+	FC "github.com/IBM/fp-go/internal/functor"
 )
 
 func fromPredicate[A any](a A, pred func(A) bool) Option[A] {
@@ -115,6 +116,10 @@ func Flatten[A any](mma Option[Option[A]]) Option[A] {
 	return MonadChain(mma, F.Identity[Option[A]])
 }
 
+func MonadAlt[A any](fa Option[A], that func() Option[A]) Option[A] {
+	return MonadFold(fa, that, Of[A])
+}
+
 func Alt[A any](that func() Option[A]) func(Option[A]) Option[A] {
 	return Fold(that, Of[A])
 }
@@ -141,3 +146,11 @@ func Reduce[A, B any](f func(B, A) B, initial B) func(Option[A]) B {
 func Filter[A any](pred func(A) bool) func(Option[A]) Option[A] {
 	return Fold(None[A], F.Ternary(pred, Of[A], F.Ignore1of1[A](None[A])))
 }
+
+func MonadFlap[A, B any](fab Option[func(A) B], a A) Option[B] {
+	return FC.MonadFlap(MonadMap[func(A) B, B], fab, a)
+}
+
+func Flap[A, B any](a A) func(Option[func(A) B]) Option[B] {
+	return F.Bind2nd(MonadFlap[A, B], a)
+}

readerio/generic/reader.go

@@ -19,6 +19,7 @@ import (
 	"sync"
 
 	F "github.com/IBM/fp-go/function"
+	FIO "github.com/IBM/fp-go/internal/fromio"
 	FR "github.com/IBM/fp-go/internal/fromreader"
 	"github.com/IBM/fp-go/internal/readert"
 	IO "github.com/IBM/fp-go/io/generic"
@@ -86,11 +87,37 @@ func Asks[GA ~func(E) A, GEA ~func(E) GIOA, GIOA ~func() A, E, A any](r GA) GEA
 }
 
 func MonadChainIOK[GEA ~func(E) GIOA, GEB ~func(E) GIOB, GIOA ~func() A, GIOB ~func() B, E, A, B any](ma GEA, f func(A) GIOB) GEB {
-	return MonadChain(ma, F.Flow2(f, FromIO[GEB]))
+	return FIO.MonadChainIOK(
+		MonadChain[GEA, GEB],
+		FromIO[GEB],
+		ma, f,
+	)
 }
 
 func ChainIOK[GEA ~func(E) GIOA, GEB ~func(E) GIOB, GIOA ~func() A, GIOB ~func() B, E, A, B any](f func(A) GIOB) func(GEA) GEB {
-	return F.Bind2nd(MonadChainIOK[GEA, GEB, GIOA, GIOB, E, A, B], f)
+	return FIO.ChainIOK(
+		MonadChain[GEA, GEB],
+		FromIO[GEB],
+		f,
+	)
+}
+
+func MonadChainFirstIOK[GEA ~func(E) GIOA, GEB ~func(E) GIOB, GIOA ~func() A, GIOB ~func() B, E, A, B any](ma GEA, f func(A) GIOB) GEA {
+	return FIO.MonadChainFirstIOK(
+		MonadChain[GEA, GEA],
+		MonadMap[GEB, GEA],
+		FromIO[GEB],
+		ma, f,
+	)
+}
+
+func ChainFirstIOK[GEA ~func(E) GIOA, GEB ~func(E) GIOB, GIOA ~func() A, GIOB ~func() B, E, A, B any](f func(A) GIOB) func(GEA) GEA {
+	return FIO.ChainFirstIOK(
+		MonadChain[GEA, GEA],
+		MonadMap[GEB, GEA],
+		FromIO[GEB],
+		f,
+	)
 }
 
 // Defer creates an IO by creating a brand new IO via a generator function, each time

readerioeither/generic/reader.go

@@ -147,6 +147,23 @@ func ChainReaderK[GEA ~func(R) GIOA, GEB ~func(R) GIOB, GIOA ~func() ET.Either[E
 	)
 }
 
+func MonadChainReaderIOK[GEA ~func(R) GIOEA, GEB ~func(R) GIOEB, GIOEA ~func() ET.Either[E, A], GIOEB ~func() ET.Either[E, B], GIOB ~func() B, GB ~func(R) GIOB, R, E, A, B any](ma GEA, f func(A) GB) GEB {
+	return FR.MonadChainReaderK(
+		MonadChain[GEA, GEB, GIOEA, GIOEB, R, E, A, B],
+		RightReaderIO[GEB, GIOEB, GB, GIOB, R, E, B],
+		ma,
+		f,
+	)
+}
+
+func ChainReaderIOK[GEA ~func(R) GIOEA, GEB ~func(R) GIOEB, GIOEA ~func() ET.Either[E, A], GIOEB ~func() ET.Either[E, B], GIOB ~func() B, GB ~func(R) GIOB, R, E, A, B any](f func(A) GB) func(GEA) GEB {
+	return FR.ChainReaderK(
+		MonadChain[GEA, GEB, GIOEA, GIOEB, R, E, A, B],
+		RightReaderIO[GEB, GIOEB, GB, GIOB, R, E, B],
+		f,
+	)
+}
+
 func MonadChainIOEitherK[GEA ~func(R) GIOA, GEB ~func(R) GIOB, GIOA ~func() ET.Either[E, A], GIOB ~func() ET.Either[E, B], R, E, A, B any](ma GEA, f func(A) GIOB) GEB {
 	return FIOE.MonadChainIOEitherK(
 		MonadChain[GEA, GEB, GIOA, GIOB, R, E, A, B],

samples/match/examples_match_test.go

@@ -0,0 +1,65 @@
+// 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 match
+
+import (
+	"fmt"
+
+	E "github.com/IBM/fp-go/either"
+	"github.com/IBM/fp-go/errors"
+	F "github.com/IBM/fp-go/function"
+	O "github.com/IBM/fp-go/option"
+	S "github.com/IBM/fp-go/string"
+)
+
+type Thing struct {
+	Name string
+}
+
+func (t Thing) GetName() string {
+	return t.Name
+}
+
+var (
+	// func(Thing) Either[error, string]
+	getName = F.Flow2(
+		Thing.GetName,
+		E.FromPredicate(S.IsNonEmpty, errors.OnSome[string]("value [%s] is empty")),
+	)
+
+	// func(option.Option[Thing]) Either[error, string]
+	GetName = F.Flow2(
+		E.FromOption[Thing](errors.OnNone("value is none")),
+		E.Chain(getName),
+	)
+)
+
+func ExampleEither_match() {
+
+	oThing := O.Of(Thing{"Carsten"})
+
+	res := F.Pipe2(
+		oThing,
+		GetName,
+		E.Fold(S.Format[error]("failed with error %v"), S.Format[string]("get value %s")),
+	)
+
+	fmt.Println(res)
+
+	// Output:
+	// get value Carsten
+
+}

semigroup/alt.go

@@ -15,8 +15,8 @@
 
 package semigroup
 
-func AltSemigroup[HKTA any](
-	falt func(HKTA, func() HKTA) HKTA,
+func AltSemigroup[HKTA any, LAZYHKTA ~func() HKTA](
+	falt func(HKTA, LAZYHKTA) HKTA,
 
 ) Semigroup[HKTA] {