fix: add missing Memoize to readers

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

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/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,
@@ -551,3 +573,13 @@ func MonadAlt[LAZY ~func() GEA, GEA ~func(context.Context) GIOA, GIOA ~func() E.
 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/reader.go

@@ -61,6 +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)
 }
@@ -147,6 +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]]()
@@ -201,3 +213,10 @@ func MonadAlt[A any](first ReaderIOEither[A], second L.Lazy[ReaderIOEither[A]])
 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)
+}

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)
 )
 

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/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
 }

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/close.go

@@ -1,29 +0,0 @@
-// 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 (
-	"io"
-
-	IOE "github.com/IBM/fp-go/ioeither"
-)
-
-// 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()
-	})
-}

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/ioeither.go

@@ -75,10 +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)
 }
@@ -167,27 +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)
 }

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

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/generic/reader.go

@@ -406,3 +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

@@ -264,3 +264,11 @@ func MonadAlt[R, E, A any](first ReaderIOEither[R, E, A], second L.Lazy[ReaderIO
 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))
+}

tuple/gen.go

@@ -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
 }