fix: add missing Memoize to readers

Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com>

cli/pipe.go

@@ -25,6 +25,40 @@ import (
 	C "github.com/urfave/cli/v2"
 )
 
+func generateUnsliced(f *os.File, i int) {
+	// Create the optionize version
+	fmt.Fprintf(f, "\n// Unsliced%d converts a function taking a slice parameter into a function with %d parameters\n", i, i)
+	fmt.Fprintf(f, "func Unsliced%d[F ~func([]T) R, T, R any](f F) func(", i)
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T")
+	}
+	fmt.Fprintf(f, ") R {\n")
+	fmt.Fprintf(f, "  return func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "t%d", j+1)
+	}
+	if i > 0 {
+		fmt.Fprintf(f, " T")
+	}
+	fmt.Fprintf(f, ") R {\n")
+	fmt.Fprintf(f, "    return f([]T{")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "t%d", j+1)
+	}
+	fmt.Fprintln(f, "})")
+	fmt.Fprintln(f, "  }")
+	fmt.Fprintln(f, "}")
+}
+
 func generateVariadic(f *os.File, i int) {
 	// Create the nullary version
 	fmt.Fprintf(f, "\n// Variadic%d converts a function taking %d parameters and a final slice into a function with %d parameters but a final variadic argument\n", i, i, i)
@@ -83,7 +117,7 @@ func generateVariadic(f *os.File, i int) {
 	fmt.Fprintf(f, "v)\n")
 	fmt.Fprintf(f, "  }\n")
 
-	fmt.Fprintf(f, "}")
+	fmt.Fprintf(f, "}\n")
 }
 
 func generateUnvariadic(f *os.File, i int) {
@@ -144,7 +178,7 @@ func generateUnvariadic(f *os.File, i int) {
 	fmt.Fprintf(f, "v...)\n")
 	fmt.Fprintf(f, "  }\n")
 
-	fmt.Fprintf(f, "}")
+	fmt.Fprintf(f, "}\n")
 }
 
 func generateNullary(f *os.File, i int) {
@@ -347,6 +381,8 @@ func generatePipeHelpers(filename string, count int) error {
 	generateVariadic(f, 0)
 	// unvariadic
 	generateUnvariadic(f, 0)
+	// unsliced
+	generateUnsliced(f, 0)
 
 	for i := 1; i <= count; i++ {
 
@@ -364,6 +400,8 @@ func generatePipeHelpers(filename string, count int) error {
 		generateVariadic(f, i)
 		// unvariadic
 		generateUnvariadic(f, i)
+		// unsliced
+		generateUnsliced(f, i)
 	}
 
 	return nil

cli/tuple.go

@@ -338,7 +338,7 @@ func generateUntupled(f *os.File, i int) {
 
 func generateTupled(f *os.File, i int) {
 	// Create the optionize version
-	fmt.Fprintf(f, "\n// Tupled%d converts a function with %d parameters returning into a function taking a Tuple%d\n// The inverse function is [Untupled%d]\n", i, i, i, i)
+	fmt.Fprintf(f, "\n// Tupled%d converts a function with %d parameters into a function taking a Tuple%d\n// The inverse function is [Untupled%d]\n", i, i, i, i)
 	fmt.Fprintf(f, "func Tupled%d[F ~func(", i)
 	for j := 0; j < i; j++ {
 		if j > 0 {

context/readerio/reader.go

@@ -18,6 +18,7 @@ package readerio
 import (
 	"context"
 
+	L "github.com/IBM/fp-go/lazy"
 	R "github.com/IBM/fp-go/readerio/generic"
 )
 
@@ -54,6 +55,13 @@ func Ask() ReaderIO[context.Context] {
 }
 
 // Defer creates an IO by creating a brand new IO via a generator function, each time
-func Defer[A any](gen func() ReaderIO[A]) ReaderIO[A] {
+func Defer[A any](gen L.Lazy[ReaderIO[A]]) ReaderIO[A] {
 	return R.Defer[ReaderIO[A]](gen)
 }
+
+// Memoize computes the value of the provided [ReaderIO] monad lazily but exactly once
+// The context used to compute the value is the context of the first call, so do not use this
+// method if the value has a functional dependency on the content of the context
+func Memoize[A any](rdr ReaderIO[A]) ReaderIO[A] {
+	return R.Memoize[ReaderIO[A]](rdr)
+}

context/readerioeither/file/file.go

@@ -25,25 +25,31 @@ import (
 	F "github.com/IBM/fp-go/function"
 	"github.com/IBM/fp-go/internal/file"
 	IOE "github.com/IBM/fp-go/ioeither"
+	IOEF "github.com/IBM/fp-go/ioeither/file"
 )
 
 var (
-	openIOE = IOE.Eitherize1(os.Open)
 	// Open opens a file for reading within the given context
 	Open = F.Flow3(
-		openIOE,
+		IOEF.Open,
 		RIOE.FromIOEither[*os.File],
 		RIOE.WithContext[*os.File],
 	)
+
+	// Remove removes a file by name
+	Remove = F.Flow2(
+		IOEF.Remove,
+		RIOE.FromIOEither[string],
+	)
 )
 
 // Close closes an object
 func Close[C io.Closer](c C) RIOE.ReaderIOEither[any] {
-	return RIOE.FromIOEither(func() ET.Either[error, any] {
-		return ET.TryCatchError(func() (any, error) {
-			return c, c.Close()
-		})
-	})
+	return F.Pipe2(
+		c,
+		IOEF.Close[C],
+		RIOE.FromIOEither[any],
+	)
 }
 
 // ReadFile reads a file in the scope of a context

context/readerioeither/file/tempfile.go

@@ -0,0 +1,53 @@
+// 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 file
+
+import (
+	"os"
+
+	RIOE "github.com/IBM/fp-go/context/readerioeither"
+	FL "github.com/IBM/fp-go/file"
+	F "github.com/IBM/fp-go/function"
+	IO "github.com/IBM/fp-go/io"
+	IOF "github.com/IBM/fp-go/io/file"
+	IOEF "github.com/IBM/fp-go/ioeither/file"
+)
+
+var (
+	// onCreateTempFile creates a temp file with sensible defaults
+	onCreateTempFile = CreateTemp("", "*")
+	// destroy handler
+	onReleaseTempFile = F.Flow4(
+		IOF.Close[*os.File],
+		IO.Map(FL.GetName),
+		RIOE.FromIO[string],
+		RIOE.Chain(Remove),
+	)
+)
+
+// CreateTemp created a temp file with proper parametrization
+func CreateTemp(dir, pattern string) RIOE.ReaderIOEither[*os.File] {
+	return F.Pipe2(
+		IOEF.CreateTemp(dir, pattern),
+		RIOE.FromIOEither[*os.File],
+		RIOE.WithContext[*os.File],
+	)
+}
+
+// WithTempFile creates a temporary file, then invokes a callback to create a resource based on the file, then close and remove the temp file
+func WithTempFile[A any](f func(*os.File) RIOE.ReaderIOEither[A]) RIOE.ReaderIOEither[A] {
+	return RIOE.WithResource[A](onCreateTempFile, onReleaseTempFile)(f)
+}

context/readerioeither/file/tempfile_test.go

@@ -0,0 +1,47 @@
+// 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 file
+
+import (
+	"context"
+	"os"
+	"testing"
+
+	RIOE "github.com/IBM/fp-go/context/readerioeither"
+	E "github.com/IBM/fp-go/either"
+	F "github.com/IBM/fp-go/function"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestWithTempFile(t *testing.T) {
+
+	res := WithTempFile(onWriteAll[*os.File]([]byte("Carsten")))
+
+	assert.Equal(t, E.Of[error]([]byte("Carsten")), res(context.Background())())
+}
+
+func TestWithTempFileOnClosedFile(t *testing.T) {
+
+	res := WithTempFile(func(f *os.File) RIOE.ReaderIOEither[[]byte] {
+		return F.Pipe2(
+			f,
+			onWriteAll[*os.File]([]byte("Carsten")),
+			RIOE.ChainFirst(F.Constant1[[]byte](Close(f))),
+		)
+	})
+
+	assert.Equal(t, E.Of[error]([]byte("Carsten")), res(context.Background())())
+}

context/readerioeither/file/write.go

@@ -0,0 +1,57 @@
+// 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 file
+
+import (
+	"context"
+	"io"
+
+	RIOE "github.com/IBM/fp-go/context/readerioeither"
+	F "github.com/IBM/fp-go/function"
+)
+
+func onWriteAll[W io.Writer](data []byte) func(w W) RIOE.ReaderIOEither[[]byte] {
+	return func(w W) RIOE.ReaderIOEither[[]byte] {
+		return F.Pipe1(
+			RIOE.TryCatch(func(ctx context.Context) func() ([]byte, error) {
+				return func() ([]byte, error) {
+					_, err := w.Write(data)
+					return data, err
+				}
+			}),
+			RIOE.WithContext[[]byte],
+		)
+	}
+}
+
+// WriteAll uses a generator function to create a stream, writes data to it and closes it
+func WriteAll[W io.WriteCloser](data []byte) func(acquire RIOE.ReaderIOEither[W]) RIOE.ReaderIOEither[[]byte] {
+	onWrite := onWriteAll[W](data)
+	return func(onCreate RIOE.ReaderIOEither[W]) RIOE.ReaderIOEither[[]byte] {
+		return RIOE.WithResource[[]byte](
+			onCreate,
+			Close[W])(
+			onWrite,
+		)
+	}
+}
+
+// Write uses a generator function to create a stream, writes data to it and closes it
+func Write[R any, W io.WriteCloser](acquire RIOE.ReaderIOEither[W]) func(use func(W) RIOE.ReaderIOEither[R]) RIOE.ReaderIOEither[R] {
+	return RIOE.WithResource[R](
+		acquire,
+		Close[W])
+}

context/readerioeither/gen.go

@@ -2,7 +2,7 @@ package readerioeither
 
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-17 22:58:56.457404 +0200 CEST m=+0.024265101
+// 2023-09-12 13:44:14.1022311 +0200 CEST m=+0.017763401
 
 import (
 	"context"

context/readerioeither/generic/gen.go

@@ -2,7 +2,7 @@ package generic
 
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-17 22:58:56.457404 +0200 CEST m=+0.024265101
+// 2023-09-12 13:44:14.1036885 +0200 CEST m=+0.019220801
 
 import (
 	"context"

context/readerioeither/generic/monoid.go

@@ -0,0 +1,56 @@
+//   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 generic
+
+import (
+	"context"
+
+	ET "github.com/IBM/fp-go/either"
+	M "github.com/IBM/fp-go/monoid"
+)
+
+func ApplicativeMonoid[GRA ~func(context.Context) GIOA, GRFA ~func(context.Context) GIOFA, GIOA ~func() ET.Either[error, A], GIOFA ~func() ET.Either[error, func(A) A], A any](
+	m M.Monoid[A],
+) M.Monoid[GRA] {
+	return M.ApplicativeMonoid(
+		Of[GRA],
+		MonadMap[GRA, GRFA],
+		MonadAp[GRA, GRA, GRFA],
+		m,
+	)
+}
+
+func ApplicativeMonoidSeq[GRA ~func(context.Context) GIOA, GRFA ~func(context.Context) GIOFA, GIOA ~func() ET.Either[error, A], GIOFA ~func() ET.Either[error, func(A) A], A any](
+	m M.Monoid[A],
+) M.Monoid[GRA] {
+	return M.ApplicativeMonoid(
+		Of[GRA],
+		MonadMap[GRA, GRFA],
+		MonadApSeq[GRA, GRA, GRFA],
+		m,
+	)
+}
+
+func ApplicativeMonoidPar[GRA ~func(context.Context) GIOA, GRFA ~func(context.Context) GIOFA, GIOA ~func() ET.Either[error, A], GIOFA ~func() ET.Either[error, func(A) A], A any](
+	m M.Monoid[A],
+) M.Monoid[GRA] {
+	return M.ApplicativeMonoid(
+		Of[GRA],
+		MonadMap[GRA, GRFA],
+		MonadApPar[GRA, GRA, GRFA],
+		m,
+	)
+}

context/readerioeither/generic/reader.go

@@ -100,6 +100,28 @@ func Map[
 	return RIE.Map[GRA, GRB](f)
 }
 
+func MonadMapTo[
+	GRA ~func(context.Context) GIOA,
+	GRB ~func(context.Context) GIOB,
+
+	GIOA ~func() E.Either[error, A],
+	GIOB ~func() E.Either[error, B],
+
+	A, B any](fa GRA, b B) GRB {
+	return RIE.MonadMapTo[GRA, GRB](fa, b)
+}
+
+func MapTo[
+	GRA ~func(context.Context) GIOA,
+	GRB ~func(context.Context) GIOB,
+
+	GIOA ~func() E.Either[error, A],
+	GIOB ~func() E.Either[error, B],
+
+	A, B any](b B) func(GRA) GRB {
+	return RIE.MapTo[GRA, GRB](b)
+}
+
 func MonadChain[
 	GRA ~func(context.Context) GIOA,
 	GRB ~func(context.Context) GIOB,
@@ -543,3 +565,21 @@ func TryCatch[
 	A any](f func(context.Context) func() (A, error)) GRA {
 	return RIE.TryCatch[GRA](f, ER.IdentityError)
 }
+
+func MonadAlt[LAZY ~func() GEA, GEA ~func(context.Context) GIOA, GIOA ~func() E.Either[error, A], A any](first GEA, second LAZY) GEA {
+	return RIE.MonadAlt(first, second)
+}
+
+func Alt[LAZY ~func() GEA, GEA ~func(context.Context) GIOA, GIOA ~func() E.Either[error, A], A any](second LAZY) func(GEA) GEA {
+	return RIE.Alt(second)
+}
+
+// Memoize computes the value of the provided monad lazily but exactly once
+// The context used to compute the value is the context of the first call, so do not use this
+// method if the value has a functional dependency on the content of the context
+func Memoize[
+	GRA ~func(context.Context) GIOA,
+	GIOA ~func() E.Either[error, A],
+	A any](rdr GRA) GRA {
+	return RIE.Memoize[GRA](rdr)
+}

context/readerioeither/generic/semigroup.go

@@ -0,0 +1,29 @@
+//   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 generic
+
+import (
+	"context"
+
+	ET "github.com/IBM/fp-go/either"
+	S "github.com/IBM/fp-go/semigroup"
+)
+
+func AltSemigroup[GRA ~func(context.Context) GIOA, GIOA ~func() ET.Either[error, A], A any]() S.Semigroup[GRA] {
+	return S.AltSemigroup(
+		MonadAlt[func() GRA],
+	)
+}

context/readerioeither/monoid.go

@@ -0,0 +1,36 @@
+//   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 readerioeither
+
+import (
+	G "github.com/IBM/fp-go/context/readerioeither/generic"
+	M "github.com/IBM/fp-go/monoid"
+)
+
+// ApplicativeMonoid returns a [Monoid] that concatenates [ReaderIOEither] instances via their applicative
+func ApplicativeMonoid[A any](m M.Monoid[A]) M.Monoid[ReaderIOEither[A]] {
+	return G.ApplicativeMonoid[ReaderIOEither[A], ReaderIOEither[func(A) A]](m)
+}
+
+// ApplicativeMonoidSeq returns a [Monoid] that concatenates [ReaderIOEither] instances via their applicative
+func ApplicativeMonoidSeq[A any](m M.Monoid[A]) M.Monoid[ReaderIOEither[A]] {
+	return G.ApplicativeMonoidSeq[ReaderIOEither[A], ReaderIOEither[func(A) A]](m)
+}
+
+// ApplicativeMonoidPar returns a [Monoid] that concatenates [ReaderIOEither] instances via their applicative
+func ApplicativeMonoidPar[A any](m M.Monoid[A]) M.Monoid[ReaderIOEither[A]] {
+	return G.ApplicativeMonoidPar[ReaderIOEither[A], ReaderIOEither[func(A) A]](m)
+}

context/readerioeither/reader.go

@@ -25,6 +25,7 @@ import (
 	ET "github.com/IBM/fp-go/either"
 	IO "github.com/IBM/fp-go/io"
 	IOE "github.com/IBM/fp-go/ioeither"
+	L "github.com/IBM/fp-go/lazy"
 	O "github.com/IBM/fp-go/option"
 )
 
@@ -60,6 +61,14 @@ func Map[A, B any](f func(A) B) func(ReaderIOEither[A]) ReaderIOEither[B] {
 	return G.Map[ReaderIOEither[A], ReaderIOEither[B]](f)
 }
 
+func MonadMapTo[A, B any](fa ReaderIOEither[A], b B) ReaderIOEither[B] {
+	return G.MonadMapTo[ReaderIOEither[A], ReaderIOEither[B]](fa, b)
+}
+
+func MapTo[A, B any](b B) func(ReaderIOEither[A]) ReaderIOEither[B] {
+	return G.MapTo[ReaderIOEither[A], ReaderIOEither[B]](b)
+}
+
 func MonadChain[A, B any](ma ReaderIOEither[A], f func(A) ReaderIOEither[B]) ReaderIOEither[B] {
 	return G.MonadChain(ma, f)
 }
@@ -146,6 +155,10 @@ func FromIO[A any](t IO.IO[A]) ReaderIOEither[A] {
 	return G.FromIO[ReaderIOEither[A]](t)
 }
 
+func FromLazy[A any](t L.Lazy[A]) ReaderIOEither[A] {
+	return G.FromIO[ReaderIOEither[A]](t)
+}
+
 // Never returns a 'ReaderIOEither' that never returns, except if its context gets canceled
 func Never[A any]() ReaderIOEither[A] {
 	return G.Never[ReaderIOEither[A]]()
@@ -182,7 +195,7 @@ func Timer(delay time.Duration) ReaderIOEither[time.Time] {
 }
 
 // Defer creates an IO by creating a brand new IO via a generator function, each time
-func Defer[A any](gen func() ReaderIOEither[A]) ReaderIOEither[A] {
+func Defer[A any](gen L.Lazy[ReaderIOEither[A]]) ReaderIOEither[A] {
 	return G.Defer[ReaderIOEither[A]](gen)
 }
 
@@ -190,3 +203,20 @@ func Defer[A any](gen func() ReaderIOEither[A]) ReaderIOEither[A] {
 func TryCatch[A any](f func(context.Context) func() (A, error)) ReaderIOEither[A] {
 	return G.TryCatch[ReaderIOEither[A]](f)
 }
+
+// MonadAlt identifies an associative operation on a type constructor
+func MonadAlt[A any](first ReaderIOEither[A], second L.Lazy[ReaderIOEither[A]]) ReaderIOEither[A] {
+	return G.MonadAlt(first, second)
+}
+
+// Alt identifies an associative operation on a type constructor
+func Alt[A any](second L.Lazy[ReaderIOEither[A]]) func(ReaderIOEither[A]) ReaderIOEither[A] {
+	return G.Alt(second)
+}
+
+// Memoize computes the value of the provided [ReaderIOEither] monad lazily but exactly once
+// The context used to compute the value is the context of the first call, so do not use this
+// method if the value has a functional dependency on the content of the context
+func Memoize[A any](rdr ReaderIOEither[A]) ReaderIOEither[A] {
+	return G.Memoize[ReaderIOEither[A]](rdr)
+}

context/readerioeither/reader_test.go

@@ -162,3 +162,125 @@ func TestRegularApply(t *testing.T) {
 	res := applied(context.Background())()
 	assert.Equal(t, E.Of[error]("CARSTEN"), res)
 }
+
+func TestWithResourceNoErrors(t *testing.T) {
+	var countAcquire, countBody, countRelease int
+
+	acquire := FromLazy(func() int {
+		countAcquire++
+		return countAcquire
+	})
+
+	release := func(int) ReaderIOEither[int] {
+		return FromLazy(func() int {
+			countRelease++
+			return countRelease
+		})
+	}
+
+	body := func(int) ReaderIOEither[int] {
+		return FromLazy(func() int {
+			countBody++
+			return countBody
+		})
+	}
+
+	resRIOE := WithResource[int](acquire, release)(body)
+
+	res := resRIOE(context.Background())()
+
+	assert.Equal(t, 1, countAcquire)
+	assert.Equal(t, 1, countBody)
+	assert.Equal(t, 1, countRelease)
+	assert.Equal(t, E.Of[error](1), res)
+}
+
+func TestWithResourceErrorInBody(t *testing.T) {
+	var countAcquire, countBody, countRelease int
+
+	acquire := FromLazy(func() int {
+		countAcquire++
+		return countAcquire
+	})
+
+	release := func(int) ReaderIOEither[int] {
+		return FromLazy(func() int {
+			countRelease++
+			return countRelease
+		})
+	}
+
+	err := fmt.Errorf("error in body")
+	body := func(int) ReaderIOEither[int] {
+		return Left[int](err)
+	}
+
+	resRIOE := WithResource[int](acquire, release)(body)
+
+	res := resRIOE(context.Background())()
+
+	assert.Equal(t, 1, countAcquire)
+	assert.Equal(t, 0, countBody)
+	assert.Equal(t, 1, countRelease)
+	assert.Equal(t, E.Left[int](err), res)
+}
+
+func TestWithResourceErrorInAcquire(t *testing.T) {
+	var countAcquire, countBody, countRelease int
+
+	err := fmt.Errorf("error in acquire")
+	acquire := Left[int](err)
+
+	release := func(int) ReaderIOEither[int] {
+		return FromLazy(func() int {
+			countRelease++
+			return countRelease
+		})
+	}
+
+	body := func(int) ReaderIOEither[int] {
+		return FromLazy(func() int {
+			countBody++
+			return countBody
+		})
+	}
+
+	resRIOE := WithResource[int](acquire, release)(body)
+
+	res := resRIOE(context.Background())()
+
+	assert.Equal(t, 0, countAcquire)
+	assert.Equal(t, 0, countBody)
+	assert.Equal(t, 0, countRelease)
+	assert.Equal(t, E.Left[int](err), res)
+}
+
+func TestWithResourceErrorInRelease(t *testing.T) {
+	var countAcquire, countBody, countRelease int
+
+	acquire := FromLazy(func() int {
+		countAcquire++
+		return countAcquire
+	})
+
+	err := fmt.Errorf("error in release")
+	release := func(int) ReaderIOEither[int] {
+		return Left[int](err)
+	}
+
+	body := func(int) ReaderIOEither[int] {
+		return FromLazy(func() int {
+			countBody++
+			return countBody
+		})
+	}
+
+	resRIOE := WithResource[int](acquire, release)(body)
+
+	res := resRIOE(context.Background())()
+
+	assert.Equal(t, 1, countAcquire)
+	assert.Equal(t, 1, countBody)
+	assert.Equal(t, 0, countRelease)
+	assert.Equal(t, E.Left[int](err), res)
+}

context/readerioeither/semigroup.go

@@ -0,0 +1,26 @@
+//   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 readerioeither
+
+import (
+	G "github.com/IBM/fp-go/context/readerioeither/generic"
+	S "github.com/IBM/fp-go/semigroup"
+)
+
+// AltSemigroup is a [Semigroup] that tries the first item and then the second one using an alternative
+func AltSemigroup[A any]() S.Semigroup[ReaderIOEither[A]] {
+	return G.AltSemigroup[ReaderIOEither[A]]()
+}

coverage.bat

@@ -0,0 +1,2 @@
+@echo off
+go tool cover -html=build/cover.out -o build/cover.html

either/apply.go

@@ -24,6 +24,7 @@ func ApplySemigroup[E, A any](s S.Semigroup[A]) S.Semigroup[Either[E, A]] {
 	return S.ApplySemigroup(MonadMap[E, A, func(A) A], MonadAp[A, E, A], s)
 }
 
+// ApplicativeMonoid returns a [Monoid] that concatenates [Either] instances via their applicative
 func ApplicativeMonoid[E, A any](m M.Monoid[A]) M.Monoid[Either[E, A]] {
 	return M.ApplicativeMonoid(Of[E, A], MonadMap[E, A, func(A) A], MonadAp[A, E, A], m)
 }

either/exec/exec.go

@@ -27,7 +27,7 @@ import (
 var (
 	// Command executes a command
 	// use this version if the command does not produce any side effect, i.e. if the output is uniquely determined by by the input
-	// typically you'd rather use the IOEither version of the command
+	// typically you'd rather use the [IOEither] version of the command
 	Command = F.Curry3(command)
 )
 

either/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-17 22:58:57.9925506 +0200 CEST m=+0.033401101
+// 2023-09-12 13:44:15.6356542 +0200 CEST m=+0.009418901
 
 package either
 

exec/exec.go

@@ -20,11 +20,14 @@ import (
 )
 
 type (
-	// command output
+	// CommandOutput represents the output of executing a command. The first field in the [Tuple2] is
+	// stdout, the second one is stderr. Use [StdOut] and [StdErr] to access these fields
 	CommandOutput = T.Tuple2[[]byte, []byte]
 )
 
 var (
+	// StdOut returns the field of a [CommandOutput] representing `stdout`
 	StdOut = T.First[[]byte, []byte]
+	// StdErr returns the field of a [CommandOutput] representing `stderr`
 	StdErr = T.Second[[]byte, []byte]
 )

function/bind.go

@@ -26,6 +26,7 @@ func Bind2nd[T1, T2, R any](f func(T1, T2) R, t2 T2) func(T1) R {
 	}
 }
 
+// SK function (SKI combinator calculus).
 func SK[T1, T2 any](_ T1, t2 T2) T2 {
 	return t2
 }

function/binds.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-17 22:59:01.9404821 +0200 CEST m=+0.161366801
+// 2023-09-12 13:44:23.4226437 +0200 CEST m=+0.011841001
 
 package function
 

function/function.go

@@ -62,6 +62,7 @@ func First[T1, T2 any](t1 T1, _ T2) T1 {
 }
 
 // Second returns the second out of two input values
+// Identical to [SK]
 func Second[T1, T2 any](_ T1, t2 T2) T2 {
 	return t2
 }

function/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-17 22:58:59.8663985 +0200 CEST m=+0.103744101
+// 2023-09-12 13:44:17.0002767 +0200 CEST m=+0.008233101
 
 package function
 
@@ -24,6 +24,13 @@ func Unvariadic0[V, R any](f func(...V) R) func([]V) R {
 	}
 }
 
+// Unsliced0 converts a function taking a slice parameter into a function with 0 parameters
+func Unsliced0[F ~func([]T) R, T, R any](f F) func() R {
+	return func() R {
+		return f([]T{})
+	}
+}
+
 // Pipe1 takes an initial value t0 and successively applies 1 functions where the input of a function is the return value of the previous function
 // The final return value is the result of the last function application
 func Pipe1[F1 ~func(T0) T1, T0, T1 any](t0 T0, f1 F1) T1 {
@@ -76,6 +83,13 @@ func Unvariadic1[T1, V, R any](f func(T1, ...V) R) func(T1, []V) R {
 	}
 }
 
+// Unsliced1 converts a function taking a slice parameter into a function with 1 parameters
+func Unsliced1[F ~func([]T) R, T, R any](f F) func(T) R {
+	return func(t1 T) R {
+		return f([]T{t1})
+	}
+}
+
 // Pipe2 takes an initial value t0 and successively applies 2 functions where the input of a function is the return value of the previous function
 // The final return value is the result of the last function application
 func Pipe2[F1 ~func(T0) T1, F2 ~func(T1) T2, T0, T1, T2 any](t0 T0, f1 F1, f2 F2) T2 {
@@ -131,6 +145,13 @@ func Unvariadic2[T1, T2, V, R any](f func(T1, T2, ...V) R) func(T1, T2, []V) R {
 	}
 }
 
+// Unsliced2 converts a function taking a slice parameter into a function with 2 parameters
+func Unsliced2[F ~func([]T) R, T, R any](f F) func(T, T) R {
+	return func(t1, t2 T) R {
+		return f([]T{t1, t2})
+	}
+}
+
 // Pipe3 takes an initial value t0 and successively applies 3 functions where the input of a function is the return value of the previous function
 // The final return value is the result of the last function application
 func Pipe3[F1 ~func(T0) T1, F2 ~func(T1) T2, F3 ~func(T2) T3, T0, T1, T2, T3 any](t0 T0, f1 F1, f2 F2, f3 F3) T3 {
@@ -189,6 +210,13 @@ func Unvariadic3[T1, T2, T3, V, R any](f func(T1, T2, T3, ...V) R) func(T1, T2,
 	}
 }
 
+// Unsliced3 converts a function taking a slice parameter into a function with 3 parameters
+func Unsliced3[F ~func([]T) R, T, R any](f F) func(T, T, T) R {
+	return func(t1, t2, t3 T) R {
+		return f([]T{t1, t2, t3})
+	}
+}
+
 // Pipe4 takes an initial value t0 and successively applies 4 functions where the input of a function is the return value of the previous function
 // The final return value is the result of the last function application
 func Pipe4[F1 ~func(T0) T1, F2 ~func(T1) T2, F3 ~func(T2) T3, F4 ~func(T3) T4, T0, T1, T2, T3, T4 any](t0 T0, f1 F1, f2 F2, f3 F3, f4 F4) T4 {
@@ -250,6 +278,13 @@ func Unvariadic4[T1, T2, T3, T4, V, R any](f func(T1, T2, T3, T4, ...V) R) func(
 	}
 }
 
+// Unsliced4 converts a function taking a slice parameter into a function with 4 parameters
+func Unsliced4[F ~func([]T) R, T, R any](f F) func(T, T, T, T) R {
+	return func(t1, t2, t3, t4 T) R {
+		return f([]T{t1, t2, t3, t4})
+	}
+}
+
 // Pipe5 takes an initial value t0 and successively applies 5 functions where the input of a function is the return value of the previous function
 // The final return value is the result of the last function application
 func Pipe5[F1 ~func(T0) T1, F2 ~func(T1) T2, F3 ~func(T2) T3, F4 ~func(T3) T4, F5 ~func(T4) T5, T0, T1, T2, T3, T4, T5 any](t0 T0, f1 F1, f2 F2, f3 F3, f4 F4, f5 F5) T5 {
@@ -314,6 +349,13 @@ func Unvariadic5[T1, T2, T3, T4, T5, V, R any](f func(T1, T2, T3, T4, T5, ...V)
 	}
 }
 
+// Unsliced5 converts a function taking a slice parameter into a function with 5 parameters
+func Unsliced5[F ~func([]T) R, T, R any](f F) func(T, T, T, T, T) R {
+	return func(t1, t2, t3, t4, t5 T) R {
+		return f([]T{t1, t2, t3, t4, t5})
+	}
+}
+
 // Pipe6 takes an initial value t0 and successively applies 6 functions where the input of a function is the return value of the previous function
 // The final return value is the result of the last function application
 func Pipe6[F1 ~func(T0) T1, F2 ~func(T1) T2, F3 ~func(T2) T3, F4 ~func(T3) T4, F5 ~func(T4) T5, F6 ~func(T5) T6, T0, T1, T2, T3, T4, T5, T6 any](t0 T0, f1 F1, f2 F2, f3 F3, f4 F4, f5 F5, f6 F6) T6 {
@@ -381,6 +423,13 @@ func Unvariadic6[T1, T2, T3, T4, T5, T6, V, R any](f func(T1, T2, T3, T4, T5, T6
 	}
 }
 
+// Unsliced6 converts a function taking a slice parameter into a function with 6 parameters
+func Unsliced6[F ~func([]T) R, T, R any](f F) func(T, T, T, T, T, T) R {
+	return func(t1, t2, t3, t4, t5, t6 T) R {
+		return f([]T{t1, t2, t3, t4, t5, t6})
+	}
+}
+
 // Pipe7 takes an initial value t0 and successively applies 7 functions where the input of a function is the return value of the previous function
 // The final return value is the result of the last function application
 func Pipe7[F1 ~func(T0) T1, F2 ~func(T1) T2, F3 ~func(T2) T3, F4 ~func(T3) T4, F5 ~func(T4) T5, F6 ~func(T5) T6, F7 ~func(T6) T7, T0, T1, T2, T3, T4, T5, T6, T7 any](t0 T0, f1 F1, f2 F2, f3 F3, f4 F4, f5 F5, f6 F6, f7 F7) T7 {
@@ -451,6 +500,13 @@ func Unvariadic7[T1, T2, T3, T4, T5, T6, T7, V, R any](f func(T1, T2, T3, T4, T5
 	}
 }
 
+// Unsliced7 converts a function taking a slice parameter into a function with 7 parameters
+func Unsliced7[F ~func([]T) R, T, R any](f F) func(T, T, T, T, T, T, T) R {
+	return func(t1, t2, t3, t4, t5, t6, t7 T) R {
+		return f([]T{t1, t2, t3, t4, t5, t6, t7})
+	}
+}
+
 // Pipe8 takes an initial value t0 and successively applies 8 functions where the input of a function is the return value of the previous function
 // The final return value is the result of the last function application
 func Pipe8[F1 ~func(T0) T1, F2 ~func(T1) T2, F3 ~func(T2) T3, F4 ~func(T3) T4, F5 ~func(T4) T5, F6 ~func(T5) T6, F7 ~func(T6) T7, F8 ~func(T7) T8, T0, T1, T2, T3, T4, T5, T6, T7, T8 any](t0 T0, f1 F1, f2 F2, f3 F3, f4 F4, f5 F5, f6 F6, f7 F7, f8 F8) T8 {
@@ -524,6 +580,13 @@ func Unvariadic8[T1, T2, T3, T4, T5, T6, T7, T8, V, R any](f func(T1, T2, T3, T4
 	}
 }
 
+// Unsliced8 converts a function taking a slice parameter into a function with 8 parameters
+func Unsliced8[F ~func([]T) R, T, R any](f F) func(T, T, T, T, T, T, T, T) R {
+	return func(t1, t2, t3, t4, t5, t6, t7, t8 T) R {
+		return f([]T{t1, t2, t3, t4, t5, t6, t7, t8})
+	}
+}
+
 // Pipe9 takes an initial value t0 and successively applies 9 functions where the input of a function is the return value of the previous function
 // The final return value is the result of the last function application
 func Pipe9[F1 ~func(T0) T1, F2 ~func(T1) T2, F3 ~func(T2) T3, F4 ~func(T3) T4, F5 ~func(T4) T5, F6 ~func(T5) T6, F7 ~func(T6) T7, F8 ~func(T7) T8, F9 ~func(T8) T9, T0, T1, T2, T3, T4, T5, T6, T7, T8, T9 any](t0 T0, f1 F1, f2 F2, f3 F3, f4 F4, f5 F5, f6 F6, f7 F7, f8 F8, f9 F9) T9 {
@@ -600,6 +663,13 @@ func Unvariadic9[T1, T2, T3, T4, T5, T6, T7, T8, T9, V, R any](f func(T1, T2, T3
 	}
 }
 
+// Unsliced9 converts a function taking a slice parameter into a function with 9 parameters
+func Unsliced9[F ~func([]T) R, T, R any](f F) func(T, T, T, T, T, T, T, T, T) R {
+	return func(t1, t2, t3, t4, t5, t6, t7, t8, t9 T) R {
+		return f([]T{t1, t2, t3, t4, t5, t6, t7, t8, t9})
+	}
+}
+
 // Pipe10 takes an initial value t0 and successively applies 10 functions where the input of a function is the return value of the previous function
 // The final return value is the result of the last function application
 func Pipe10[F1 ~func(T0) T1, F2 ~func(T1) T2, F3 ~func(T2) T3, F4 ~func(T3) T4, F5 ~func(T4) T5, F6 ~func(T5) T6, F7 ~func(T6) T7, F8 ~func(T7) T8, F9 ~func(T8) T9, F10 ~func(T9) T10, T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10 any](t0 T0, f1 F1, f2 F2, f3 F3, f4 F4, f5 F5, f6 F6, f7 F7, f8 F8, f9 F9, f10 F10) T10 {
@@ -679,6 +749,13 @@ func Unvariadic10[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, V, R any](f func(T1,
 	}
 }
 
+// Unsliced10 converts a function taking a slice parameter into a function with 10 parameters
+func Unsliced10[F ~func([]T) R, T, R any](f F) func(T, T, T, T, T, T, T, T, T, T) R {
+	return func(t1, t2, t3, t4, t5, t6, t7, t8, t9, t10 T) R {
+		return f([]T{t1, t2, t3, t4, t5, t6, t7, t8, t9, t10})
+	}
+}
+
 // Pipe11 takes an initial value t0 and successively applies 11 functions where the input of a function is the return value of the previous function
 // The final return value is the result of the last function application
 func Pipe11[F1 ~func(T0) T1, F2 ~func(T1) T2, F3 ~func(T2) T3, F4 ~func(T3) T4, F5 ~func(T4) T5, F6 ~func(T5) T6, F7 ~func(T6) T7, F8 ~func(T7) T8, F9 ~func(T8) T9, F10 ~func(T9) T10, F11 ~func(T10) T11, T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11 any](t0 T0, f1 F1, f2 F2, f3 F3, f4 F4, f5 F5, f6 F6, f7 F7, f8 F8, f9 F9, f10 F10, f11 F11) T11 {
@@ -761,6 +838,13 @@ func Unvariadic11[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, V, R any](f func
 	}
 }
 
+// Unsliced11 converts a function taking a slice parameter into a function with 11 parameters
+func Unsliced11[F ~func([]T) R, T, R any](f F) func(T, T, T, T, T, T, T, T, T, T, T) R {
+	return func(t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11 T) R {
+		return f([]T{t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11})
+	}
+}
+
 // Pipe12 takes an initial value t0 and successively applies 12 functions where the input of a function is the return value of the previous function
 // The final return value is the result of the last function application
 func Pipe12[F1 ~func(T0) T1, F2 ~func(T1) T2, F3 ~func(T2) T3, F4 ~func(T3) T4, F5 ~func(T4) T5, F6 ~func(T5) T6, F7 ~func(T6) T7, F8 ~func(T7) T8, F9 ~func(T8) T9, F10 ~func(T9) T10, F11 ~func(T10) T11, F12 ~func(T11) T12, T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12 any](t0 T0, f1 F1, f2 F2, f3 F3, f4 F4, f5 F5, f6 F6, f7 F7, f8 F8, f9 F9, f10 F10, f11 F11, f12 F12) T12 {
@@ -846,6 +930,13 @@ func Unvariadic12[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, V, R any](f
 	}
 }
 
+// Unsliced12 converts a function taking a slice parameter into a function with 12 parameters
+func Unsliced12[F ~func([]T) R, T, R any](f F) func(T, T, T, T, T, T, T, T, T, T, T, T) R {
+	return func(t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11, t12 T) R {
+		return f([]T{t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11, t12})
+	}
+}
+
 // Pipe13 takes an initial value t0 and successively applies 13 functions where the input of a function is the return value of the previous function
 // The final return value is the result of the last function application
 func Pipe13[F1 ~func(T0) T1, F2 ~func(T1) T2, F3 ~func(T2) T3, F4 ~func(T3) T4, F5 ~func(T4) T5, F6 ~func(T5) T6, F7 ~func(T6) T7, F8 ~func(T7) T8, F9 ~func(T8) T9, F10 ~func(T9) T10, F11 ~func(T10) T11, F12 ~func(T11) T12, F13 ~func(T12) T13, T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13 any](t0 T0, f1 F1, f2 F2, f3 F3, f4 F4, f5 F5, f6 F6, f7 F7, f8 F8, f9 F9, f10 F10, f11 F11, f12 F12, f13 F13) T13 {
@@ -934,6 +1025,13 @@ func Unvariadic13[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, V, R a
 	}
 }
 
+// Unsliced13 converts a function taking a slice parameter into a function with 13 parameters
+func Unsliced13[F ~func([]T) R, T, R any](f F) func(T, T, T, T, T, T, T, T, T, T, T, T, T) R {
+	return func(t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11, t12, t13 T) R {
+		return f([]T{t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11, t12, t13})
+	}
+}
+
 // Pipe14 takes an initial value t0 and successively applies 14 functions where the input of a function is the return value of the previous function
 // The final return value is the result of the last function application
 func Pipe14[F1 ~func(T0) T1, F2 ~func(T1) T2, F3 ~func(T2) T3, F4 ~func(T3) T4, F5 ~func(T4) T5, F6 ~func(T5) T6, F7 ~func(T6) T7, F8 ~func(T7) T8, F9 ~func(T8) T9, F10 ~func(T9) T10, F11 ~func(T10) T11, F12 ~func(T11) T12, F13 ~func(T12) T13, F14 ~func(T13) T14, T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14 any](t0 T0, f1 F1, f2 F2, f3 F3, f4 F4, f5 F5, f6 F6, f7 F7, f8 F8, f9 F9, f10 F10, f11 F11, f12 F12, f13 F13, f14 F14) T14 {
@@ -1025,6 +1123,13 @@ func Unvariadic14[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, V
 	}
 }
 
+// Unsliced14 converts a function taking a slice parameter into a function with 14 parameters
+func Unsliced14[F ~func([]T) R, T, R any](f F) func(T, T, T, T, T, T, T, T, T, T, T, T, T, T) R {
+	return func(t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11, t12, t13, t14 T) R {
+		return f([]T{t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11, t12, t13, t14})
+	}
+}
+
 // Pipe15 takes an initial value t0 and successively applies 15 functions where the input of a function is the return value of the previous function
 // The final return value is the result of the last function application
 func Pipe15[F1 ~func(T0) T1, F2 ~func(T1) T2, F3 ~func(T2) T3, F4 ~func(T3) T4, F5 ~func(T4) T5, F6 ~func(T5) T6, F7 ~func(T6) T7, F8 ~func(T7) T8, F9 ~func(T8) T9, F10 ~func(T9) T10, F11 ~func(T10) T11, F12 ~func(T11) T12, F13 ~func(T12) T13, F14 ~func(T13) T14, F15 ~func(T14) T15, T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15 any](t0 T0, f1 F1, f2 F2, f3 F3, f4 F4, f5 F5, f6 F6, f7 F7, f8 F8, f9 F9, f10 F10, f11 F11, f12 F12, f13 F13, f14 F14, f15 F15) T15 {
@@ -1119,6 +1224,13 @@ func Unvariadic15[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T
 	}
 }
 
+// Unsliced15 converts a function taking a slice parameter into a function with 15 parameters
+func Unsliced15[F ~func([]T) R, T, R any](f F) func(T, T, T, T, T, T, T, T, T, T, T, T, T, T, T) R {
+	return func(t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11, t12, t13, t14, t15 T) R {
+		return f([]T{t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11, t12, t13, t14, t15})
+	}
+}
+
 // Pipe16 takes an initial value t0 and successively applies 16 functions where the input of a function is the return value of the previous function
 // The final return value is the result of the last function application
 func Pipe16[F1 ~func(T0) T1, F2 ~func(T1) T2, F3 ~func(T2) T3, F4 ~func(T3) T4, F5 ~func(T4) T5, F6 ~func(T5) T6, F7 ~func(T6) T7, F8 ~func(T7) T8, F9 ~func(T8) T9, F10 ~func(T9) T10, F11 ~func(T10) T11, F12 ~func(T11) T12, F13 ~func(T12) T13, F14 ~func(T13) T14, F15 ~func(T14) T15, F16 ~func(T15) T16, T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16 any](t0 T0, f1 F1, f2 F2, f3 F3, f4 F4, f5 F5, f6 F6, f7 F7, f8 F8, f9 F9, f10 F10, f11 F11, f12 F12, f13 F13, f14 F14, f15 F15, f16 F16) T16 {
@@ -1216,6 +1328,13 @@ func Unvariadic16[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T
 	}
 }
 
+// Unsliced16 converts a function taking a slice parameter into a function with 16 parameters
+func Unsliced16[F ~func([]T) R, T, R any](f F) func(T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T) R {
+	return func(t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11, t12, t13, t14, t15, t16 T) R {
+		return f([]T{t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11, t12, t13, t14, t15, t16})
+	}
+}
+
 // Pipe17 takes an initial value t0 and successively applies 17 functions where the input of a function is the return value of the previous function
 // The final return value is the result of the last function application
 func Pipe17[F1 ~func(T0) T1, F2 ~func(T1) T2, F3 ~func(T2) T3, F4 ~func(T3) T4, F5 ~func(T4) T5, F6 ~func(T5) T6, F7 ~func(T6) T7, F8 ~func(T7) T8, F9 ~func(T8) T9, F10 ~func(T9) T10, F11 ~func(T10) T11, F12 ~func(T11) T12, F13 ~func(T12) T13, F14 ~func(T13) T14, F15 ~func(T14) T15, F16 ~func(T15) T16, F17 ~func(T16) T17, T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17 any](t0 T0, f1 F1, f2 F2, f3 F3, f4 F4, f5 F5, f6 F6, f7 F7, f8 F8, f9 F9, f10 F10, f11 F11, f12 F12, f13 F13, f14 F14, f15 F15, f16 F16, f17 F17) T17 {
@@ -1316,6 +1435,13 @@ func Unvariadic17[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T
 	}
 }
 
+// Unsliced17 converts a function taking a slice parameter into a function with 17 parameters
+func Unsliced17[F ~func([]T) R, T, R any](f F) func(T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T) R {
+	return func(t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11, t12, t13, t14, t15, t16, t17 T) R {
+		return f([]T{t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11, t12, t13, t14, t15, t16, t17})
+	}
+}
+
 // Pipe18 takes an initial value t0 and successively applies 18 functions where the input of a function is the return value of the previous function
 // The final return value is the result of the last function application
 func Pipe18[F1 ~func(T0) T1, F2 ~func(T1) T2, F3 ~func(T2) T3, F4 ~func(T3) T4, F5 ~func(T4) T5, F6 ~func(T5) T6, F7 ~func(T6) T7, F8 ~func(T7) T8, F9 ~func(T8) T9, F10 ~func(T9) T10, F11 ~func(T10) T11, F12 ~func(T11) T12, F13 ~func(T12) T13, F14 ~func(T13) T14, F15 ~func(T14) T15, F16 ~func(T15) T16, F17 ~func(T16) T17, F18 ~func(T17) T18, T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18 any](t0 T0, f1 F1, f2 F2, f3 F3, f4 F4, f5 F5, f6 F6, f7 F7, f8 F8, f9 F9, f10 F10, f11 F11, f12 F12, f13 F13, f14 F14, f15 F15, f16 F16, f17 F17, f18 F18) T18 {
@@ -1419,6 +1545,13 @@ func Unvariadic18[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T
 	}
 }
 
+// Unsliced18 converts a function taking a slice parameter into a function with 18 parameters
+func Unsliced18[F ~func([]T) R, T, R any](f F) func(T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T) R {
+	return func(t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11, t12, t13, t14, t15, t16, t17, t18 T) R {
+		return f([]T{t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11, t12, t13, t14, t15, t16, t17, t18})
+	}
+}
+
 // Pipe19 takes an initial value t0 and successively applies 19 functions where the input of a function is the return value of the previous function
 // The final return value is the result of the last function application
 func Pipe19[F1 ~func(T0) T1, F2 ~func(T1) T2, F3 ~func(T2) T3, F4 ~func(T3) T4, F5 ~func(T4) T5, F6 ~func(T5) T6, F7 ~func(T6) T7, F8 ~func(T7) T8, F9 ~func(T8) T9, F10 ~func(T9) T10, F11 ~func(T10) T11, F12 ~func(T11) T12, F13 ~func(T12) T13, F14 ~func(T13) T14, F15 ~func(T14) T15, F16 ~func(T15) T16, F17 ~func(T16) T17, F18 ~func(T17) T18, F19 ~func(T18) T19, T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19 any](t0 T0, f1 F1, f2 F2, f3 F3, f4 F4, f5 F5, f6 F6, f7 F7, f8 F8, f9 F9, f10 F10, f11 F11, f12 F12, f13 F13, f14 F14, f15 F15, f16 F16, f17 F17, f18 F18, f19 F19) T19 {
@@ -1525,6 +1658,13 @@ func Unvariadic19[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T
 	}
 }
 
+// Unsliced19 converts a function taking a slice parameter into a function with 19 parameters
+func Unsliced19[F ~func([]T) R, T, R any](f F) func(T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T) R {
+	return func(t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11, t12, t13, t14, t15, t16, t17, t18, t19 T) R {
+		return f([]T{t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11, t12, t13, t14, t15, t16, t17, t18, t19})
+	}
+}
+
 // Pipe20 takes an initial value t0 and successively applies 20 functions where the input of a function is the return value of the previous function
 // The final return value is the result of the last function application
 func Pipe20[F1 ~func(T0) T1, F2 ~func(T1) T2, F3 ~func(T2) T3, F4 ~func(T3) T4, F5 ~func(T4) T5, F6 ~func(T5) T6, F7 ~func(T6) T7, F8 ~func(T7) T8, F9 ~func(T8) T9, F10 ~func(T9) T10, F11 ~func(T10) T11, F12 ~func(T11) T12, F13 ~func(T12) T13, F14 ~func(T13) T14, F15 ~func(T14) T15, F16 ~func(T15) T16, F17 ~func(T16) T17, F18 ~func(T17) T18, F19 ~func(T18) T19, F20 ~func(T19) T20, T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20 any](t0 T0, f1 F1, f2 F2, f3 F3, f4 F4, f5 F5, f6 F6, f7 F7, f8 F8, f9 F9, f10 F10, f11 F11, f12 F12, f13 F13, f14 F14, f15 F15, f16 F16, f17 F17, f18 F18, f19 F19, f20 F20) T20 {
@@ -1633,3 +1773,10 @@ func Unvariadic20[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T
 		return f(t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11, t12, t13, t14, t15, t16, t17, t18, t19, t20, v...)
 	}
 }
+
+// Unsliced20 converts a function taking a slice parameter into a function with 20 parameters
+func Unsliced20[F ~func([]T) R, T, R any](f F) func(T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T) R {
+	return func(t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11, t12, t13, t14, t15, t16, t17, t18, t19, t20 T) R {
+		return f([]T{t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11, t12, t13, t14, t15, t16, t17, t18, t19, t20})
+	}
+}

function/unvariadic_test.go

@@ -0,0 +1,45 @@
+// 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 function
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func fromLibrary(data ...string) string {
+	return strings.Join(data, "-")
+}
+
+func TestUnvariadic(t *testing.T) {
+
+	res := Pipe1(
+		[]string{"A", "B"},
+		Unvariadic0(fromLibrary),
+	)
+
+	assert.Equal(t, "A-B", res)
+}
+
+func TestVariadicArity(t *testing.T) {
+
+	f := Unsliced2(Unvariadic0(fromLibrary))
+
+	res := f("A", "B")
+	assert.Equal(t, "A-B", res)
+}

identity/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-17 22:59:06.2987136 +0200 CEST m=+0.049156901
+// 2023-09-12 13:44:24.9409324 +0200 CEST m=+0.008573601
 
 package identity
 

internal/apply/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-17 22:59:08.1313362 +0200 CEST m=+0.111171801
+// 2023-09-12 13:44:26.2499883 +0200 CEST m=+0.007601301
 
 package apply
 

internal/eithert/either.go

@@ -22,6 +22,16 @@ import (
 	FC "github.com/IBM/fp-go/internal/functor"
 )
 
+func MonadAlt[LAZY ~func() HKTFA, E, A, HKTFA any](
+	fof func(ET.Either[E, A]) HKTFA,
+	fchain func(HKTFA, func(ET.Either[E, A]) HKTFA) HKTFA,
+
+	first HKTFA,
+	second LAZY) HKTFA {
+
+	return fchain(first, ET.Fold(F.Ignore1of1[E](second), F.Flow2(ET.Of[E, A], fof)))
+}
+
 // HKTFA = HKT<F, Either<E, A>>
 // HKTFB = HKT<F, Either<E, B>>
 func MonadMap[E, A, B, HKTFA, HKTFB any](fmap func(HKTFA, func(ET.Either[E, A]) ET.Either[E, B]) HKTFB, fa HKTFA, f func(A) B) HKTFB {

io/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-17 22:59:10.1040409 +0200 CEST m=+0.089470201
+// 2023-09-12 13:44:27.9813739 +0200 CEST m=+0.011088001
 
 package io
 

io/generic/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-17 22:59:10.1132645 +0200 CEST m=+0.098693801
+// 2023-09-12 13:44:27.9813739 +0200 CEST m=+0.011088001
 package generic
 
 import (

io/io.go

@@ -84,7 +84,7 @@ func Flatten[A any](mma IO[IO[A]]) IO[A] {
 	return G.Flatten(mma)
 }
 
-// Memoize computes the value of the provided IO monad lazily but exactly once
+// Memoize computes the value of the provided [IO] monad lazily but exactly once
 func Memoize[A any](ma IO[A]) IO[A] {
 	return G.Memoize(ma)
 }

ioeither/file/file.go

@@ -16,6 +16,7 @@
 package file
 
 import (
+	"io"
 	"os"
 
 	IOE "github.com/IBM/fp-go/ioeither"
@@ -45,3 +46,10 @@ func Remove(name string) IOE.IOEither[error, string] {
 		return name, os.Remove(name)
 	})
 }
+
+// Close closes an object
+func Close[C io.Closer](c C) IOE.IOEither[error, any] {
+	return IOE.TryCatchError(func() (any, error) {
+		return c, c.Close()
+	})
+}

ioeither/file/readall.go

@@ -31,7 +31,7 @@ func onReadAll[R io.Reader](r R) IOE.IOEither[error, []byte] {
 func ReadAll[R io.ReadCloser](acquire IOE.IOEither[error, R]) IOE.IOEither[error, []byte] {
 	return IOE.WithResource[[]byte](
 		acquire,
-		onClose[R])(
+		Close[R])(
 		onReadAll[R],
 	)
 }

ioeither/file/tempfile_test.go

@@ -38,7 +38,7 @@ func TestWithTempFileOnClosedFile(t *testing.T) {
 		return F.Pipe2(
 			f,
 			onWriteAll[*os.File]([]byte("Carsten")),
-			IOE.ChainFirst(F.Constant1[[]byte](onClose(f))),
+			IOE.ChainFirst(F.Constant1[[]byte](Close(f))),
 		)
 	})
 

ioeither/file/write.go

@@ -36,7 +36,7 @@ func WriteAll[W io.WriteCloser](data []byte) func(acquire IOE.IOEither[error, W]
 	return func(onCreate IOE.IOEither[error, W]) IOE.IOEither[error, []byte] {
 		return IOE.WithResource[[]byte](
 			onCreate,
-			onClose[W])(
+			Close[W])(
 			onWrite,
 		)
 	}
@@ -46,5 +46,5 @@ func WriteAll[W io.WriteCloser](data []byte) func(acquire IOE.IOEither[error, W]
 func Write[R any, W io.WriteCloser](acquire IOE.IOEither[error, W]) func(use func(W) IOE.IOEither[error, R]) IOE.IOEither[error, R] {
 	return IOE.WithResource[R](
 		acquire,
-		onClose[W])
+		Close[W])
 }

ioeither/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-17 22:59:12.0033119 +0200 CEST m=+0.096740401
+// 2023-09-12 13:44:29.4935658 +0200 CEST m=+0.015377401
 
 package ioeither
 

ioeither/generic/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-17 22:59:12.0246635 +0200 CEST m=+0.118092001
+// 2023-09-12 13:44:29.4935658 +0200 CEST m=+0.015377401
 package generic
 
 import (

ioeither/generic/ioeither.go

@@ -290,3 +290,17 @@ func FromImpure[GA ~func() ET.Either[E, any], IMP ~func(), E any](f IMP) GA {
 func Defer[GEA ~func() ET.Either[E, A], E, A any](gen func() GEA) GEA {
 	return IO.Defer[GEA](gen)
 }
+
+func MonadAlt[LAZY ~func() GIOA, GIOA ~func() ET.Either[E, A], E, A any](first GIOA, second LAZY) GIOA {
+	return eithert.MonadAlt(
+		IO.Of[GIOA],
+		IO.MonadChain[GIOA, GIOA],
+
+		first,
+		second,
+	)
+}
+
+func Alt[LAZY ~func() GIOA, GIOA ~func() ET.Either[E, A], E, A any](second LAZY) func(GIOA) GIOA {
+	return F.Bind2nd(MonadAlt[LAZY], second)
+}

ioeither/generic/monoid.go

@@ -0,0 +1,54 @@
+//   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 generic
+
+import (
+	ET "github.com/IBM/fp-go/either"
+	M "github.com/IBM/fp-go/monoid"
+)
+
+func ApplicativeMonoid[GEA ~func() ET.Either[E, A], GEFA ~func() ET.Either[E, func(A) A], E, A any](
+	m M.Monoid[A],
+) M.Monoid[GEA] {
+	return M.ApplicativeMonoid(
+		MonadOf[GEA],
+		MonadMap[GEA, GEFA],
+		MonadAp[GEA, GEFA, GEA],
+		m,
+	)
+}
+
+func ApplicativeMonoidSeq[GEA ~func() ET.Either[E, A], GEFA ~func() ET.Either[E, func(A) A], E, A any](
+	m M.Monoid[A],
+) M.Monoid[GEA] {
+	return M.ApplicativeMonoid(
+		MonadOf[GEA],
+		MonadMap[GEA, GEFA],
+		MonadApSeq[GEA, GEFA, GEA],
+		m,
+	)
+}
+
+func ApplicativeMonoidPar[GEA ~func() ET.Either[E, A], GEFA ~func() ET.Either[E, func(A) A], E, A any](
+	m M.Monoid[A],
+) M.Monoid[GEA] {
+	return M.ApplicativeMonoid(
+		MonadOf[GEA],
+		MonadMap[GEA, GEFA],
+		MonadApPar[GEA, GEFA, GEA],
+		m,
+	)
+}

ioeither/generic/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 generic
+
+import (
+	ET "github.com/IBM/fp-go/either"
+	S "github.com/IBM/fp-go/semigroup"
+)
+
+func AltSemigroup[GIOA ~func() ET.Either[E, A], E, A any]() S.Semigroup[GIOA] {
+	return S.AltSemigroup(
+		MonadAlt[func() GIOA],
+	)
+}

ioeither/ioeither.go

@@ -19,6 +19,7 @@ import (
 	ET "github.com/IBM/fp-go/either"
 	I "github.com/IBM/fp-go/io"
 	G "github.com/IBM/fp-go/ioeither/generic"
+	L "github.com/IBM/fp-go/lazy"
 	O "github.com/IBM/fp-go/option"
 )
 
@@ -74,10 +75,20 @@ func ChainIOK[E, A, B any](f func(A) I.IO[B]) func(IOEither[E, A]) IOEither[E, B
 	return G.ChainIOK[IOEither[E, A], IOEither[E, B]](f)
 }
 
+func ChainLazyK[E, A, B any](f func(A) L.Lazy[B]) func(IOEither[E, A]) IOEither[E, B] {
+	return G.ChainIOK[IOEither[E, A], IOEither[E, B]](f)
+}
+
+// FromIO creates an [IOEither] from an [IO] instance, invoking [IO] for each invocation of [IOEither]
 func FromIO[E, A any](mr I.IO[A]) IOEither[E, A] {
 	return G.FromIO[IOEither[E, A]](mr)
 }
 
+// FromLazy creates an [IOEither] from a [Lazy] instance, invoking [Lazy] for each invocation of [IOEither]
+func FromLazy[E, A any](mr L.Lazy[A]) IOEither[E, A] {
+	return G.FromIO[IOEither[E, A]](mr)
+}
+
 func MonadMap[E, A, B any](fa IOEither[E, A], f func(A) B) IOEither[E, B] {
 	return G.MonadMap[IOEither[E, A], IOEither[E, B]](fa, f)
 }
@@ -166,27 +177,27 @@ func MonadChainTo[E, A, B any](fa IOEither[E, A], fb IOEither[E, B]) IOEither[E,
 	return G.MonadChainTo(fa, fb)
 }
 
-// ChainTo composes to the second monad ignoring the return value of the first
+// ChainTo composes to the second [IOEither] monad ignoring the return value of the first
 func ChainTo[E, A, B any](fb IOEither[E, B]) func(IOEither[E, A]) IOEither[E, B] {
 	return G.ChainTo[IOEither[E, A]](fb)
 }
 
-// MonadChainFirst runs the monad returned by the function but returns the result of the original monad
+// MonadChainFirst runs the [IOEither] monad returned by the function but returns the result of the original monad
 func MonadChainFirst[E, A, B any](ma IOEither[E, A], f func(A) IOEither[E, B]) IOEither[E, A] {
 	return G.MonadChainFirst(ma, f)
 }
 
-// ChainFirst runs the monad returned by the function but returns the result of the original monad
+// ChainFirst runs the [IOEither] monad returned by the function but returns the result of the original monad
 func ChainFirst[E, A, B any](f func(A) IOEither[E, B]) func(IOEither[E, A]) IOEither[E, A] {
 	return G.ChainFirst[IOEither[E, A]](f)
 }
 
-// MonadChainFirstIOK runs the monad returned by the function but returns the result of the original monad
+// MonadChainFirstIOK runs [IO] the monad returned by the function but returns the result of the original monad
 func MonadChainFirstIOK[E, A, B any](ma IOEither[E, A], f func(A) I.IO[B]) IOEither[E, A] {
 	return G.MonadChainFirstIOK(ma, f)
 }
 
-// ChainFirsIOKt runs the monad returned by the function but returns the result of the original monad
+// ChainFirstIOK runs the [IO] monad returned by the function but returns the result of the original monad
 func ChainFirstIOK[E, A, B any](f func(A) I.IO[B]) func(IOEither[E, A]) IOEither[E, A] {
 	return G.ChainFirstIOK[IOEither[E, A]](f)
 }
@@ -207,6 +218,16 @@ func FromImpure[E any](f func()) IOEither[E, any] {
 }
 
 // Defer creates an IO by creating a brand new IO via a generator function, each time
-func Defer[E, A any](gen func() IOEither[E, A]) IOEither[E, A] {
+func Defer[E, A any](gen L.Lazy[IOEither[E, A]]) IOEither[E, A] {
 	return G.Defer[IOEither[E, A]](gen)
 }
+
+// MonadAlt identifies an associative operation on a type constructor
+func MonadAlt[E, A any](first IOEither[E, A], second L.Lazy[IOEither[E, A]]) IOEither[E, A] {
+	return G.MonadAlt(first, second)
+}
+
+// Alt identifies an associative operation on a type constructor
+func Alt[E, A any](second L.Lazy[IOEither[E, A]]) func(IOEither[E, A]) IOEither[E, A] {
+	return G.Alt(second)
+}

ioeither/monoid.go

@@ -0,0 +1,42 @@
+//   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 ioeither
+
+import (
+	G "github.com/IBM/fp-go/ioeither/generic"
+	M "github.com/IBM/fp-go/monoid"
+)
+
+// ApplicativeMonoid returns a [Monoid] that concatenates [IOEither] instances via their applicative
+func ApplicativeMonoid[E, A any](
+	m M.Monoid[A],
+) M.Monoid[IOEither[E, A]] {
+	return G.ApplicativeMonoid[IOEither[E, A], IOEither[E, func(A) A]](m)
+}
+
+// ApplicativeMonoid returns a [Monoid] that concatenates [IOEither] instances via their applicative
+func ApplicativeMonoidSeq[E, A any](
+	m M.Monoid[A],
+) M.Monoid[IOEither[E, A]] {
+	return G.ApplicativeMonoidSeq[IOEither[E, A], IOEither[E, func(A) A]](m)
+}
+
+// ApplicativeMonoid returns a [Monoid] that concatenates [IOEither] instances via their applicative
+func ApplicativeMonoidPar[E, A any](
+	m M.Monoid[A],
+) M.Monoid[IOEither[E, A]] {
+	return G.ApplicativeMonoid[IOEither[E, A], IOEither[E, func(A) A]](m)
+}

ioeither/monoid_test.go

@@ -0,0 +1,42 @@
+//   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 ioeither
+
+import (
+	"fmt"
+	"testing"
+
+	E "github.com/IBM/fp-go/either"
+	S "github.com/IBM/fp-go/string"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestApplicativeMonoid(t *testing.T) {
+	m := ApplicativeMonoid[error](S.Monoid)
+
+	// good cases
+	assert.Equal(t, E.Of[error]("ab"), m.Concat(Of[error]("a"), Of[error]("b"))())
+	assert.Equal(t, E.Of[error]("a"), m.Concat(Of[error]("a"), m.Empty())())
+	assert.Equal(t, E.Of[error]("b"), m.Concat(m.Empty(), Of[error]("b"))())
+
+	// bad cases
+	e1 := fmt.Errorf("e1")
+	e2 := fmt.Errorf("e1")
+
+	assert.Equal(t, E.Left[string](e1), m.Concat(Left[string](e1), Of[error]("b"))())
+	assert.Equal(t, E.Left[string](e1), m.Concat(Left[string](e1), Left[string](e2))())
+	assert.Equal(t, E.Left[string](e2), m.Concat(Of[error]("a"), Left[string](e2))())
+}

ioeither/semigroup.go

@@ -0,0 +1,26 @@
+// 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 ioeither
+
+import (
+	G "github.com/IBM/fp-go/ioeither/generic"
+	S "github.com/IBM/fp-go/semigroup"
+)
+
+// AltSemigroup is a [Semigroup] that tries the first item and then the second one using an alternative
+func AltSemigroup[E, A any]() S.Semigroup[IOEither[E, A]] {
+	return G.AltSemigroup[IOEither[E, A]]()
+}

iooption/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-17 22:59:14.0582736 +0200 CEST m=+0.248503201
+// 2023-09-12 13:44:32.1514823 +0200 CEST m=+0.098931001
 
 package iooption
 

iooption/generic/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-17 22:59:14.0642289 +0200 CEST m=+0.254458501
+// 2023-09-12 13:44:32.1546277 +0200 CEST m=+0.102076401
 package generic
 
 import (

iooption/generic/iooption.go

@@ -18,6 +18,7 @@ package generic
 import (
 	"time"
 
+	ET "github.com/IBM/fp-go/either"
 	F "github.com/IBM/fp-go/function"
 	FI "github.com/IBM/fp-go/internal/fromio"
 	"github.com/IBM/fp-go/internal/optiont"
@@ -55,6 +56,21 @@ func FromOption[GA ~func() O.Option[A], A any](o O.Option[A]) GA {
 	return IO.Of[GA](o)
 }
 
+func FromEither[GA ~func() O.Option[A], E, A any](e ET.Either[E, A]) GA {
+	return F.Pipe2(
+		e,
+		ET.ToOption[E, A],
+		FromOption[GA],
+	)
+}
+
+func FromIOEither[GA ~func() O.Option[A], GEA ~func() ET.Either[E, A], E, A any](ioe GEA) GA {
+	return F.Pipe1(
+		ioe,
+		IO.Map[GEA, GA](ET.ToOption[E, A]),
+	)
+}
+
 func MonadMap[GA ~func() O.Option[A], GB ~func() O.Option[B], A, B any](fa GA, f func(A) B) GB {
 	return optiont.MonadMap(IO.MonadMap[GA, GB, O.Option[A], O.Option[B]], fa, f)
 }

iooption/iooption.go

@@ -16,7 +16,9 @@
 package iooption
 
 import (
+	ET "github.com/IBM/fp-go/either"
 	I "github.com/IBM/fp-go/io"
+	IOE "github.com/IBM/fp-go/ioeither"
 	G "github.com/IBM/fp-go/iooption/generic"
 	O "github.com/IBM/fp-go/option"
 )
@@ -117,7 +119,7 @@ func Memoize[A any](ma IOOption[A]) IOOption[A] {
 	return G.Memoize(ma)
 }
 
-// Fold convers an IOOption into an IO
+// Fold convers an [IOOption] into an [IO]
 func Fold[A, B any](onNone func() I.IO[B], onSome func(A) I.IO[B]) func(IOOption[A]) I.IO[B] {
 	return G.Fold[IOOption[A]](onNone, onSome)
 }
@@ -126,3 +128,13 @@ func Fold[A, B any](onNone func() I.IO[B], onSome func(A) I.IO[B]) func(IOOption
 func Defer[A any](gen func() IOOption[A]) IOOption[A] {
 	return G.Defer[IOOption[A]](gen)
 }
+
+// FromIOEither converts an [IOEither] into an [IOOption]
+func FromIOEither[E, A any](ioe IOE.IOEither[E, A]) IOOption[A] {
+	return G.FromIOEither[IOOption[A]](ioe)
+}
+
+// FromEither converts an [Either] into an [IOOption]
+func FromEither[E, A any](e ET.Either[E, A]) IOOption[A] {
+	return G.FromEither[IOOption[A]](e)
+}

iterator/stateless/benchmark_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 stateless
+
+import (
+	"testing"
+
+	F "github.com/IBM/fp-go/function"
+)
+
+func BenchmarkMulti(b *testing.B) {
+	// run the Fib function b.N times
+	for n := 0; n < b.N; n++ {
+		single()
+	}
+}
+
+func single() int64 {
+
+	length := 10000
+	nums := make([]int, 0, length)
+	for i := 0; i < length; i++ {
+		nums = append(nums, i+1)
+	}
+
+	return F.Pipe6(
+		nums,
+		FromArray[int],
+		Filter(func(n int) bool {
+			return n%2 == 0
+		}),
+		Map(func(t int) int64 {
+			return int64(t)
+		}),
+		Filter(func(t int64) bool {
+			n := t
+			for n/10 != 0 {
+				if n%10 == 4 {
+					return false
+				}
+				n = n / 10
+			}
+			return true
+		}),
+		Map(func(t int64) int {
+			return int(t)
+		}),
+		Reduce(func(n int64, r int) int64 {
+			return n + int64(r)
+		}, int64(0)),
+	)
+}

iterator/stateless/generic/iterator.go

@@ -82,6 +82,7 @@ func Map[GV ~func() O.Option[T.Tuple2[GV, V]], GU ~func() O.Option[T.Tuple2[GU,
 			m,
 		)
 	}
+
 	m = O.Map(T.Map2(recurse, f))
 
 	return recurse

monoid/alt.go

@@ -0,0 +1,58 @@
+// 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 monoid
+
+import (
+	S "github.com/IBM/fp-go/semigroup"
+)
+
+func AlternativeMonoid[A, HKTA, HKTFA any](
+	fof func(A) HKTA,
+
+	fmap func(HKTA, func(A) func(A) A) HKTFA,
+	fap func(HKTFA, HKTA) HKTA,
+
+	falt func(HKTA, func() HKTA) HKTA,
+
+	m Monoid[A],
+
+) Monoid[HKTA] {
+
+	sg := ApplicativeMonoid(fof, fmap, fap, m)
+
+	return MakeMonoid(
+		func(first, second HKTA) HKTA {
+			snd := func() HKTA { return second }
+
+			return falt(sg.Concat(first, second), func() HKTA {
+				return falt(first, snd)
+			})
+		},
+		sg.Empty(),
+	)
+}
+
+func AltMonoid[HKTA any](
+	fzero func() HKTA,
+	falt func(HKTA, func() HKTA) HKTA,
+
+) Monoid[HKTA] {
+
+	return MakeMonoid(
+		S.AltSemigroup(falt).Concat,
+		fzero(),
+	)
+}

monoid/apply.go

@@ -20,15 +20,15 @@ import (
 )
 
 func ApplicativeMonoid[A, HKTA, HKTFA any](
-	_of func(A) HKTA,
-	_map func(HKTA, func(A) func(A) A) HKTFA,
-	_ap func(HKTFA, HKTA) HKTA,
+	fof func(A) HKTA,
+	fmap func(HKTA, func(A) func(A) A) HKTFA,
+	fap func(HKTFA, HKTA) HKTA,
 
 	m Monoid[A],
 ) Monoid[HKTA] {
 
 	return MakeMonoid(
-		S.ApplySemigroup[A](_map, _ap, m).Concat,
-		_of(m.Empty()),
+		S.ApplySemigroup[A](fmap, fap, m).Concat,
+		fof(m.Empty()),
 	)
 }

option/apply.go

@@ -24,6 +24,7 @@ func ApplySemigroup[A any](s S.Semigroup[A]) S.Semigroup[Option[A]] {
 	return S.ApplySemigroup(MonadMap[A, func(A) A], MonadAp[A, A], s)
 }
 
+// ApplicativeMonoid returns a [Monoid] that concatenates [Option] instances via their applicative
 func ApplicativeMonoid[A any](m M.Monoid[A]) M.Monoid[Option[A]] {
 	return M.ApplicativeMonoid(Of[A], MonadMap[A, func(A) A], MonadAp[A, A], m)
 }

option/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-17 22:59:16.3450991 +0200 CEST m=+0.104894201
+// 2023-09-12 13:44:34.2077257 +0200 CEST m=+0.023541001
 
 package option
 

reader/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-17 22:59:18.4448291 +0200 CEST m=+0.161369001
+// 2023-09-12 13:44:36.1655251 +0200 CEST m=+0.010000501
 
 package reader
 

reader/generic/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-17 22:59:18.5047315 +0200 CEST m=+0.221271401
+// 2023-09-12 13:44:36.166526 +0200 CEST m=+0.011001401
 package generic
 
 // From0 converts a function with 1 parameters returning a [R] into a function with 0 parameters returning a [GRA]

readerio/generic/reader.go

@@ -16,6 +16,8 @@
 package generic
 
 import (
+	"sync"
+
 	F "github.com/IBM/fp-go/function"
 	FR "github.com/IBM/fp-go/internal/fromreader"
 	"github.com/IBM/fp-go/internal/readert"
@@ -99,3 +101,26 @@ func Defer[GEA ~func(E) GA, GA ~func() A, E, A any](gen func() GEA) GEA {
 		}
 	}
 }
+
+// Memoize computes the value of the provided reader monad lazily but exactly once
+// The context used to compute the value is the context of the first call, so do not use this
+// method if the value has a functional dependency on the content of the context
+func Memoize[GEA ~func(E) GA, GA ~func() A, E, A any](rdr GEA) GEA {
+	// synchronization primitives
+	var once sync.Once
+	var result A
+	// callback
+	gen := func(e E) func() {
+		return func() {
+			result = rdr(e)()
+		}
+	}
+	// returns our memoized wrapper
+	return func(e E) GA {
+		io := gen(e)
+		return func() A {
+			once.Do(io)
+			return result
+		}
+	}
+}

readerio/reader.go

@@ -75,3 +75,10 @@ func ChainIOK[E, A, B any](f func(A) IO.IO[B]) func(ReaderIO[E, A]) ReaderIO[E,
 func Defer[E, A any](gen func() ReaderIO[E, A]) ReaderIO[E, A] {
 	return G.Defer[ReaderIO[E, A]](gen)
 }
+
+// Memoize computes the value of the provided [ReaderIO] monad lazily but exactly once
+// The context used to compute the value is the context of the first call, so do not use this
+// method if the value has a functional dependency on the content of the context
+func Memoize[E, A any](rdr ReaderIO[E, A]) ReaderIO[E, A] {
+	return G.Memoize[ReaderIO[E, A]](rdr)
+}

readerioeither/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-17 22:59:21.3704716 +0200 CEST m=+0.110126101
+// 2023-09-12 13:44:37.5566477 +0200 CEST m=+0.009011201
 
 package readerioeither
 

readerioeither/generic/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-17 22:59:21.3811525 +0200 CEST m=+0.120807001
+// 2023-09-12 13:44:37.5566477 +0200 CEST m=+0.009011201
 package generic
 
 import (

readerioeither/generic/reader.go

@@ -35,6 +35,20 @@ func MakeReader[GEA ~func(R) GIOA, GIOA ~func() ET.Either[E, A], R, E, A any](f
 	return f
 }
 
+func MonadAlt[LAZY ~func() GEA, GEA ~func(R) GIOA, GIOA ~func() ET.Either[E, A], R, E, A any](first GEA, second LAZY) GEA {
+	return eithert.MonadAlt(
+		G.Of[GEA],
+		G.MonadChain[GEA, GEA],
+
+		first,
+		second,
+	)
+}
+
+func Alt[LAZY ~func() GEA, GEA ~func(R) GIOA, GIOA ~func() ET.Either[E, A], R, E, A any](second LAZY) func(GEA) GEA {
+	return F.Bind2nd(MonadAlt[LAZY], second)
+}
+
 func MonadMap[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](fa GEA, f func(A) B) GEB {
 	return eithert.MonadMap(G.MonadMap[GEA, GEB, GIOA, GIOB, R, ET.Either[E, A], ET.Either[E, B]], fa, f)
 }
@@ -392,3 +406,11 @@ func TryCatch[GEA ~func(R) GA, GA ~func() ET.Either[E, A], R, E, A any](f func(R
 		return IOE.TryCatch[GA](f(r), onThrow)
 	}
 }
+
+// Memoize computes the value of the provided monad lazily but exactly once
+// The context used to compute the value is the context of the first call, so do not use this
+// method if the value has a functional dependency on the content of the context
+func Memoize[
+	GEA ~func(R) GIOA, GIOA ~func() ET.Either[E, A], R, E, A any](rdr GEA) GEA {
+	return G.Memoize[GEA](rdr)
+}

readerioeither/reader.go

@@ -19,6 +19,7 @@ import (
 	ET "github.com/IBM/fp-go/either"
 	"github.com/IBM/fp-go/io"
 	IOE "github.com/IBM/fp-go/ioeither"
+	L "github.com/IBM/fp-go/lazy"
 	O "github.com/IBM/fp-go/option"
 	RD "github.com/IBM/fp-go/reader"
 	RE "github.com/IBM/fp-go/readereither"
@@ -245,7 +246,7 @@ func Swap[R, E, A any](val ReaderIOEither[R, E, A]) ReaderIOEither[R, A, E] {
 }
 
 // Defer creates an IO by creating a brand new IO via a generator function, each time
-func Defer[R, E, A any](gen func() ReaderIOEither[R, E, A]) ReaderIOEither[R, E, A] {
+func Defer[R, E, A any](gen L.Lazy[ReaderIOEither[R, E, A]]) ReaderIOEither[R, E, A] {
 	return G.Defer[ReaderIOEither[R, E, A]](gen)
 }
 
@@ -253,3 +254,21 @@ func Defer[R, E, A any](gen func() ReaderIOEither[R, E, A]) ReaderIOEither[R, E,
 func TryCatch[R, E, A any](f func(R) func() (A, error), onThrow func(error) E) ReaderIOEither[R, E, A] {
 	return G.TryCatch[ReaderIOEither[R, E, A]](f, onThrow)
 }
+
+// MonadAlt identifies an associative operation on a type constructor.
+func MonadAlt[R, E, A any](first ReaderIOEither[R, E, A], second L.Lazy[ReaderIOEither[R, E, A]]) ReaderIOEither[R, E, A] {
+	return G.MonadAlt(first, second)
+}
+
+// Alt identifies an associative operation on a type constructor.
+func Alt[R, E, A any](second L.Lazy[ReaderIOEither[R, E, A]]) func(ReaderIOEither[R, E, A]) ReaderIOEither[R, E, A] {
+	return G.Alt(second)
+}
+
+// Memoize computes the value of the provided [ReaderIOEither] monad lazily but exactly once
+// The context used to compute the value is the context of the first call, so do not use this
+// method if the value has a functional dependency on the content of the context
+func Memoize[
+	R, E, A any](rdr ReaderIOEither[R, E, A]) ReaderIOEither[R, E, A] {
+	return G.Memoize[ReaderIOEither[R, E, A]](rdr)
+}

samples/http/http_test.go

@@ -74,9 +74,7 @@ func TestMultipleHttpRequests(t *testing.T) {
 	assert.Equal(t, E.Of[error](count), result())
 }
 
-// TestHeterogeneousHttpRequests shows how to execute multiple HTTP requests in parallel when
-// the response structure of these requests is different. We use [R.TraverseTuple2] to account for the different types
-func TestHeterogeneousHttpRequests(t *testing.T) {
+func heterogeneousHttpRequests() R.ReaderIOEither[T.Tuple2[PostItem, CatFact]] {
 	// prepare the http client
 	client := H.MakeClient(HTTP.DefaultClient)
 	// readSinglePost sends a GET request and parses the response as [PostItem]
@@ -84,7 +82,7 @@ func TestHeterogeneousHttpRequests(t *testing.T) {
 	// readSingleCatFact sends a GET request and parses the response as [CatFact]
 	readSingleCatFact := H.ReadJson[CatFact](client)
 
-	data := F.Pipe3(
+	return F.Pipe3(
 		T.MakeTuple2("https://jsonplaceholder.typicode.com/posts/1", "https://catfact.ninja/fact"),
 		T.Map2(H.MakeGetRequest, H.MakeGetRequest),
 		R.TraverseTuple2(
@@ -94,7 +92,21 @@ func TestHeterogeneousHttpRequests(t *testing.T) {
 		R.ChainFirstIOK(IO.Logf[T.Tuple2[PostItem, CatFact]]("Log Result: %v")),
 	)
 
+}
+
+// TestHeterogeneousHttpRequests shows how to execute multiple HTTP requests in parallel when
+// the response structure of these requests is different. We use [R.TraverseTuple2] to account for the different types
+func TestHeterogeneousHttpRequests(t *testing.T) {
+	data := heterogeneousHttpRequests()
+
 	result := data(context.Background())
 
 	fmt.Println(result())
 }
+
+// BenchmarkHeterogeneousHttpRequests shows how to execute multiple HTTP requests in parallel when
+// the response structure of these requests is different. We use [R.TraverseTuple2] to account for the different types
+func BenchmarkHeterogeneousHttpRequests(b *testing.B) {
+
+	heterogeneousHttpRequests()(context.Background())
+}

samples/tuples/option_test.go

@@ -0,0 +1,59 @@
+// 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 tuples
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"testing"
+
+	F "github.com/IBM/fp-go/function"
+	IOE "github.com/IBM/fp-go/ioeither"
+	IOEF "github.com/IBM/fp-go/ioeither/file"
+	IOEG "github.com/IBM/fp-go/ioeither/generic"
+	IOO "github.com/IBM/fp-go/iooption"
+)
+
+func TestIOEitherToOption1(t *testing.T) {
+	tmpDir := t.TempDir()
+	content := []byte("abc")
+
+	resIOO := F.Pipe2(
+		content,
+		IOEF.WriteFile(filepath.Join(tmpDir, "test.txt"), os.ModePerm),
+		IOEG.Fold[IOE.IOEither[error, []byte]](
+			IOO.Of[error],
+			F.Ignore1of1[[]byte](IOO.None[error]),
+		),
+	)
+
+	fmt.Println(resIOO())
+}
+
+func TestIOEitherToOption2(t *testing.T) {
+	tmpDir := t.TempDir()
+	content := []byte("abc")
+
+	resIOO := F.Pipe3(
+		content,
+		IOEF.WriteFile(filepath.Join(tmpDir, "test.txt"), os.ModePerm),
+		IOE.Swap[error, []byte],
+		IOO.FromIOEither[[]byte, error],
+	)
+
+	fmt.Println(resIOO())
+}

samples/tuples/samples/data.txt

@@ -0,0 +1 @@
+abc

samples/tuples/tuple_test.go

@@ -0,0 +1,130 @@
+// 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 tuples
+
+import (
+	"bytes"
+	"io"
+	"strings"
+	"testing"
+
+	E "github.com/IBM/fp-go/either"
+	F "github.com/IBM/fp-go/function"
+	IOE "github.com/IBM/fp-go/ioeither"
+	IOEF "github.com/IBM/fp-go/ioeither/file"
+	T "github.com/IBM/fp-go/tuple"
+	"github.com/stretchr/testify/assert"
+)
+
+func sampleConvertDocx(r io.Reader) (string, map[string]string, error) {
+	content, err := io.ReadAll(r)
+	return string(content), map[string]string{}, err
+}
+
+func TestSampleConvertDocx1(t *testing.T) {
+	// this conversion approach has the disadvantage that it exhausts the reader
+	// so we cannot invoke the resulting IOEither multiple times
+	convertDocx := func(r io.Reader) IOE.IOEither[error, T.Tuple2[string, map[string]string]] {
+		return IOE.TryCatchError(func() (T.Tuple2[string, map[string]string], error) {
+			text, meta, err := sampleConvertDocx(r)
+			return T.MakeTuple2(text, meta), err
+		})
+	}
+
+	rdr := strings.NewReader("abc")
+	resIOE := convertDocx(rdr)
+
+	resE := resIOE()
+
+	assert.True(t, E.IsRight(resE))
+}
+
+func TestSampleConvertDocx2(t *testing.T) {
+	// this approach assumes that `sampleConvertDocx` does not have any side effects
+	// other than reading from a `Reader`. As a consequence it can be a pure function itself.
+	// The disadvantage is that its input has to exist in memory which is probably not a good
+	// idea for large inputs
+	convertDocx := func(data []byte) E.Either[error, T.Tuple2[string, map[string]string]] {
+		return E.TryCatchError(func() (T.Tuple2[string, map[string]string], error) {
+			text, meta, err := sampleConvertDocx(bytes.NewReader(data))
+			return T.MakeTuple2(text, meta), err
+		})
+	}
+
+	resE := convertDocx([]byte("abc"))
+
+	assert.True(t, E.IsRight(resE))
+}
+
+// onClose closes a closeable resource
+func onClose[R io.Closer](r R) IOE.IOEither[error, R] {
+	return IOE.TryCatchError(func() (R, error) {
+		return r, r.Close()
+	})
+}
+
+// convertDocx3 takes an `acquire` function that creates an instance or a [ReaderCloser] whenever the resulting [IOEither] is invoked. Since
+// we return a [Closer] the instance will be closed after use, automatically. This design makes sure that the resulting [IOEither] can be invoked
+// as many times as necessary
+func convertDocx3[R io.ReadCloser](acquire IOE.IOEither[error, R]) IOE.IOEither[error, T.Tuple2[string, map[string]string]] {
+	return IOE.WithResource[T.Tuple2[string, map[string]string]](
+		acquire,
+		onClose[R])(
+		func(r R) IOE.IOEither[error, T.Tuple2[string, map[string]string]] {
+			return IOE.TryCatchError(func() (T.Tuple2[string, map[string]string], error) {
+				text, meta, err := sampleConvertDocx(r)
+				return T.MakeTuple2(text, meta), err
+			})
+		},
+	)
+}
+
+// convertDocx4 takes an `acquire` function that creates an instance or a [Reader] whenever the resulting [IOEither] is invoked.
+// This design makes sure that the resulting [IOEither] can be invoked
+// as many times as necessary
+func convertDocx4[R io.Reader](acquire IOE.IOEither[error, R]) IOE.IOEither[error, T.Tuple2[string, map[string]string]] {
+	return F.Pipe1(
+		acquire,
+		IOE.Chain(func(r R) IOE.IOEither[error, T.Tuple2[string, map[string]string]] {
+			return IOE.TryCatchError(func() (T.Tuple2[string, map[string]string], error) {
+				text, meta, err := sampleConvertDocx(r)
+				return T.MakeTuple2(text, meta), err
+			})
+		}),
+	)
+}
+
+func TestSampleConvertDocx3(t *testing.T) {
+	// IOEither that creates the reader
+	acquire := IOEF.Open("./samples/data.txt")
+
+	resIOE := convertDocx3(acquire)
+	resE := resIOE()
+
+	assert.True(t, E.IsRight(resE))
+}
+
+func TestSampleConvertDocx4(t *testing.T) {
+	// IOEither that creates the reader
+	acquire := IOE.FromIO[error](func() *strings.Reader {
+		return strings.NewReader("abc")
+	})
+
+	resIOE := convertDocx4(acquire)
+	resE := resIOE()
+
+	assert.True(t, E.IsRight(resE))
+}

semigroup/alt.go

@@ -13,17 +13,16 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package file
+package semigroup
 
-import (
-	"io"
+func AltSemigroup[HKTA any](
+	falt func(HKTA, func() HKTA) HKTA,
 
-	IOE "github.com/IBM/fp-go/ioeither"
-)
+) Semigroup[HKTA] {
 
-// onClose closes a closeable resource
-func onClose[R io.Closer](r R) IOE.IOEither[error, R] {
-	return IOE.TryCatchError(func() (R, error) {
-		return r, r.Close()
-	})
+	return MakeSemigroup(
+		func(first, second HKTA) HKTA {
+			return falt(first, func() HKTA { return second })
+		},
+	)
 }

semigroup/apply.go

@@ -25,14 +25,14 @@ HKTA = HKT<A>
 HKTFA = HKT<func(A)A>
 */
 func ApplySemigroup[A, HKTA, HKTFA any](
-	_map func(HKTA, func(A) func(A) A) HKTFA,
-	_ap func(HKTFA, HKTA) HKTA,
+	fmap func(HKTA, func(A) func(A) A) HKTFA,
+	fap func(HKTFA, HKTA) HKTA,
 
 	s Semigroup[A],
 ) Semigroup[HKTA] {
 
 	cb := F.Curry2(s.Concat)
 	return MakeSemigroup(func(first HKTA, second HKTA) HKTA {
-		return _ap(_map(first, cb), second)
+		return fap(fmap(first, cb), second)
 	})
 }

string/generic/string.go

@@ -0,0 +1,41 @@
+// 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 generic
+
+// ToBytes converts the string to bytes
+func ToBytes[T ~string](s T) []byte {
+	return []byte(s)
+}
+
+// ToRunes converts the string to runes
+func ToRunes[T ~string](s T) []rune {
+	return []rune(s)
+}
+
+// IsEmpty tests if the string is empty
+func IsEmpty[T ~string](s T) bool {
+	return len(s) == 0
+}
+
+// IsNonEmpty tests if the string is not empty
+func IsNonEmpty[T ~string](s T) bool {
+	return len(s) > 0
+}
+
+// Size returns the size of the string
+func Size[T ~string](s T) int {
+	return len(s)
+}

test.bat

@@ -0,0 +1,3 @@
+@echo off
+mkdir build 2> NUL
+gotip test .\... && go1.20.1 test .\... && go test -v -coverprofile build/cover.out -coverpkg=./... -covermode=atomic .\...

tuple/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-17 22:59:23.6923568 +0200 CEST m=+0.056359401
+// 2023-09-12 13:44:39.7573676 +0200 CEST m=+0.040374701
 
 package tuple
 
@@ -111,7 +111,7 @@ func MakeTuple1[T1 any](t1 T1) Tuple1[T1] {
 	return Tuple1[T1]{t1}
 }
 
-// Tupled1 converts a function with 1 parameters returning into a function taking a Tuple1
+// Tupled1 converts a function with 1 parameters into a function taking a Tuple1
 // The inverse function is [Untupled1]
 func Tupled1[F ~func(T1) R, T1, R any](f F) func(Tuple1[T1]) R {
 	return func(t Tuple1[T1]) R {
@@ -217,7 +217,7 @@ func MakeTuple2[T1, T2 any](t1 T1, t2 T2) Tuple2[T1, T2] {
 	return Tuple2[T1, T2]{t1, t2}
 }
 
-// Tupled2 converts a function with 2 parameters returning into a function taking a Tuple2
+// Tupled2 converts a function with 2 parameters into a function taking a Tuple2
 // The inverse function is [Untupled2]
 func Tupled2[F ~func(T1, T2) R, T1, T2, R any](f F) func(Tuple2[T1, T2]) R {
 	return func(t Tuple2[T1, T2]) R {
@@ -334,7 +334,7 @@ func MakeTuple3[T1, T2, T3 any](t1 T1, t2 T2, t3 T3) Tuple3[T1, T2, T3] {
 	return Tuple3[T1, T2, T3]{t1, t2, t3}
 }
 
-// Tupled3 converts a function with 3 parameters returning into a function taking a Tuple3
+// Tupled3 converts a function with 3 parameters into a function taking a Tuple3
 // The inverse function is [Untupled3]
 func Tupled3[F ~func(T1, T2, T3) R, T1, T2, T3, R any](f F) func(Tuple3[T1, T2, T3]) R {
 	return func(t Tuple3[T1, T2, T3]) R {
@@ -462,7 +462,7 @@ func MakeTuple4[T1, T2, T3, T4 any](t1 T1, t2 T2, t3 T3, t4 T4) Tuple4[T1, T2, T
 	return Tuple4[T1, T2, T3, T4]{t1, t2, t3, t4}
 }
 
-// Tupled4 converts a function with 4 parameters returning into a function taking a Tuple4
+// Tupled4 converts a function with 4 parameters into a function taking a Tuple4
 // The inverse function is [Untupled4]
 func Tupled4[F ~func(T1, T2, T3, T4) R, T1, T2, T3, T4, R any](f F) func(Tuple4[T1, T2, T3, T4]) R {
 	return func(t Tuple4[T1, T2, T3, T4]) R {
@@ -601,7 +601,7 @@ func MakeTuple5[T1, T2, T3, T4, T5 any](t1 T1, t2 T2, t3 T3, t4 T4, t5 T5) Tuple
 	return Tuple5[T1, T2, T3, T4, T5]{t1, t2, t3, t4, t5}
 }
 
-// Tupled5 converts a function with 5 parameters returning into a function taking a Tuple5
+// Tupled5 converts a function with 5 parameters into a function taking a Tuple5
 // The inverse function is [Untupled5]
 func Tupled5[F ~func(T1, T2, T3, T4, T5) R, T1, T2, T3, T4, T5, R any](f F) func(Tuple5[T1, T2, T3, T4, T5]) R {
 	return func(t Tuple5[T1, T2, T3, T4, T5]) R {
@@ -751,7 +751,7 @@ func MakeTuple6[T1, T2, T3, T4, T5, T6 any](t1 T1, t2 T2, t3 T3, t4 T4, t5 T5, t
 	return Tuple6[T1, T2, T3, T4, T5, T6]{t1, t2, t3, t4, t5, t6}
 }
 
-// Tupled6 converts a function with 6 parameters returning into a function taking a Tuple6
+// Tupled6 converts a function with 6 parameters into a function taking a Tuple6
 // The inverse function is [Untupled6]
 func Tupled6[F ~func(T1, T2, T3, T4, T5, T6) R, T1, T2, T3, T4, T5, T6, R any](f F) func(Tuple6[T1, T2, T3, T4, T5, T6]) R {
 	return func(t Tuple6[T1, T2, T3, T4, T5, T6]) R {
@@ -912,7 +912,7 @@ func MakeTuple7[T1, T2, T3, T4, T5, T6, T7 any](t1 T1, t2 T2, t3 T3, t4 T4, t5 T
 	return Tuple7[T1, T2, T3, T4, T5, T6, T7]{t1, t2, t3, t4, t5, t6, t7}
 }
 
-// Tupled7 converts a function with 7 parameters returning into a function taking a Tuple7
+// Tupled7 converts a function with 7 parameters into a function taking a Tuple7
 // The inverse function is [Untupled7]
 func Tupled7[F ~func(T1, T2, T3, T4, T5, T6, T7) R, T1, T2, T3, T4, T5, T6, T7, R any](f F) func(Tuple7[T1, T2, T3, T4, T5, T6, T7]) R {
 	return func(t Tuple7[T1, T2, T3, T4, T5, T6, T7]) R {
@@ -1084,7 +1084,7 @@ func MakeTuple8[T1, T2, T3, T4, T5, T6, T7, T8 any](t1 T1, t2 T2, t3 T3, t4 T4,
 	return Tuple8[T1, T2, T3, T4, T5, T6, T7, T8]{t1, t2, t3, t4, t5, t6, t7, t8}
 }
 
-// Tupled8 converts a function with 8 parameters returning into a function taking a Tuple8
+// Tupled8 converts a function with 8 parameters into a function taking a Tuple8
 // The inverse function is [Untupled8]
 func Tupled8[F ~func(T1, T2, T3, T4, T5, T6, T7, T8) R, T1, T2, T3, T4, T5, T6, T7, T8, R any](f F) func(Tuple8[T1, T2, T3, T4, T5, T6, T7, T8]) R {
 	return func(t Tuple8[T1, T2, T3, T4, T5, T6, T7, T8]) R {
@@ -1267,7 +1267,7 @@ func MakeTuple9[T1, T2, T3, T4, T5, T6, T7, T8, T9 any](t1 T1, t2 T2, t3 T3, t4
 	return Tuple9[T1, T2, T3, T4, T5, T6, T7, T8, T9]{t1, t2, t3, t4, t5, t6, t7, t8, t9}
 }
 
-// Tupled9 converts a function with 9 parameters returning into a function taking a Tuple9
+// Tupled9 converts a function with 9 parameters into a function taking a Tuple9
 // The inverse function is [Untupled9]
 func Tupled9[F ~func(T1, T2, T3, T4, T5, T6, T7, T8, T9) R, T1, T2, T3, T4, T5, T6, T7, T8, T9, R any](f F) func(Tuple9[T1, T2, T3, T4, T5, T6, T7, T8, T9]) R {
 	return func(t Tuple9[T1, T2, T3, T4, T5, T6, T7, T8, T9]) R {
@@ -1461,7 +1461,7 @@ func MakeTuple10[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10 any](t1 T1, t2 T2, t3 T
 	return Tuple10[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10]{t1, t2, t3, t4, t5, t6, t7, t8, t9, t10}
 }
 
-// Tupled10 converts a function with 10 parameters returning into a function taking a Tuple10
+// Tupled10 converts a function with 10 parameters into a function taking a Tuple10
 // The inverse function is [Untupled10]
 func Tupled10[F ~func(T1, T2, T3, T4, T5, T6, T7, T8, T9, T10) R, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, R any](f F) func(Tuple10[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10]) R {
 	return func(t Tuple10[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10]) R {

tuple/tuple.go

@@ -21,10 +21,12 @@ func Of[T1 any](t T1) Tuple1[T1] {
 	return MakeTuple1(t)
 }
 
+// First returns the first element of a [Tuple2]
 func First[T1, T2 any](t Tuple2[T1, T2]) T1 {
 	return t.F1
 }
 
+// Second returns the second element of a [Tuple2]
 func Second[T1, T2 any](t Tuple2[T1, T2]) T2 {
 	return t.F2
 }