fix: adjust Pair to Haskell semantic

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

.github/workflows/build.yml

@@ -4,9 +4,7 @@ on:
   push:
     branches:
       - main
-
   pull_request:
-
   workflow_dispatch:
     inputs:
       dryRun:
@@ -15,35 +13,59 @@ on:
         required: false
 
 env:
-  # Currently no way to detect automatically
   DEFAULT_BRANCH: main
-  GO_VERSION: 1.21.6 # renovate: datasource=golang-version depName=golang
-  NODE_VERSION: 20
+  LATEST_GO_VERSION: 1.21.6 # renovate: datasource=golang-version depName=golang
+  NODE_VERSION: 22
   DRY_RUN: true
 
 jobs:
-  build:
+  build-v1:
+    name: Build v1 (Go ${{ matrix.go-version }})
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        go-version: [ '1.20.x', '1.21.x', '1.22.x']
+        go-version: ['1.20.x', '1.21.x', '1.22.x', '1.23.x']
+      fail-fast: false  # Continue with other versions if one fails
     steps:
-      # full checkout for semantic-release
-      - uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29 # v4.1.6
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
           fetch-depth: 0
-      - name: Set up go ${{ matrix.go-version }}
+      - name: Set up Go ${{ matrix.go-version }}
         uses: actions/setup-go@v5
         with:
           go-version: ${{ matrix.go-version }}
-      -
-        name: Tests
+          cache: true  # Enable Go module caching
+      - name: Run tests
         run: |
           go mod tidy
           go test -v ./...
 
+  build-v2:
+    name: Build v2 (Go ${{ matrix.go-version }})
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        go-version: ['1.24.x']
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          fetch-depth: 0
+      - name: Set up Go ${{ matrix.go-version }}
+        uses: actions/setup-go@v5
+        with:
+          go-version: ${{ matrix.go-version }}
+          cache: true  # Enable Go module caching
+      - name: Run tests
+        run: |
+          cd v2
+          go mod tidy
+          go test -v ./...
+
   release:
-    needs: [build]
+    name: Release
+    needs: 
+      - build-v1
+      - build-v2
     if: github.repository == 'IBM/fp-go' && github.event_name != 'pull_request'
     runs-on: ubuntu-latest
     timeout-minutes: 15
@@ -51,38 +73,37 @@ jobs:
       contents: write
       issues: write
       pull-requests: write
-
     steps:
-      # full checkout for semantic-release
-      - name: Full checkout
-        uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29 # v4.1.6
+      - name: Checkout code
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
           fetch-depth: 0
 
-      - name: Set up Node.js ${{ env.NODE_VERSION }}
-        uses: actions/setup-node@60edb5dd545a775178f52524783378180af0d1f8 # v4.0.2
+      - name: Set up Node.js
+        uses: actions/setup-node@1d0ff469b7ec7b3cb9d8673fde0c81c44821de2a # v4.2.0
         with:
           node-version: ${{ env.NODE_VERSION }}
+          cache: 'npm'  # Enable npm caching
 
-      - name: Set up go ${{env.GO_VERSION}}
+      - name: Set up Go
         uses: actions/setup-go@v5
         with:
-          go-version: ${{env.GO_VERSION}}
+          go-version: ${{ env.LATEST_GO_VERSION }}
+          cache: true  # Enable Go module caching
 
-      # The dry-run evaluation is only made for non PR events. Manual trigger w/dryRun true, main branch and any tagged branches will set DRY run to false
-      - name: Check dry run
+      - name: Determine release mode
+        id: release-mode
         run: |
-          if [[ "${{github.event_name}}" == "workflow_dispatch" && "${{ github.event.inputs.dryRun }}" != "true"  ]]; then
-              echo "DRY_RUN=false" >> $GITHUB_ENV
-          elif [[ "${{github.ref}}" == "refs/heads/${{env.DEFAULT_BRANCH}}" ]]; then
+          if [[ "${{ github.event_name }}" == "workflow_dispatch" && "${{ github.event.inputs.dryRun }}" != "true" ]]; then
             echo "DRY_RUN=false" >> $GITHUB_ENV
-          elif [[ "${{github.ref}}" =~ ^refs/heads/v[0-9]+(\.[0-9]+)?$ ]]; then
+          elif [[ "${{ github.ref }}" == "refs/heads/${{ env.DEFAULT_BRANCH }}" ]]; then
+            echo "DRY_RUN=false" >> $GITHUB_ENV
+          elif [[ "${{ github.ref }}" =~ ^refs/heads/v[0-9]+(\.[0-9]+)?$ ]]; then
             echo "DRY_RUN=false" >> $GITHUB_ENV
           fi
 
-      - name: Semantic Release
+      - name: Run semantic release
         run: |
-          npx -p "conventional-changelog-conventionalcommits@<8" -p semantic-release semantic-release --dry-run ${{env.DRY_RUN}}
+          npx -p conventional-changelog-conventionalcommits -p semantic-release semantic-release --dry-run ${{ env.DRY_RUN }}
         env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-  
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.gitignore

@@ -1,4 +1,5 @@
 fp-go.exe
+fp-go
 main.exe
 build/
 .idea

README.md

@@ -29,9 +29,9 @@ This library aims to provide a set of data types and functions that make it easy
 
 ### How does this play with the [🧘🏽 Zen Of Go](https://the-zen-of-go.netlify.app/)?
 
-#### 🧘🏽 Each package fulfils a single purpose
+#### 🧘🏽 Each package fulfills a single purpose
 
-✔️ Each of the top level packages (e.g. Option, Either, ReaderIOEither, ...) fulfils the purpose of defining the respective data type and implementing the set of common operations for this data type.
+✔️ Each of the top level packages (e.g. Option, Either, ReaderIOEither, ...) fulfills the purpose of defining the respective data type and implementing the set of common operations for this data type.
 
 #### 🧘🏽 Handle errors explicitly
 

go.mod

@@ -3,15 +3,15 @@ module github.com/IBM/fp-go
 go 1.20
 
 require (
-	github.com/stretchr/testify v1.9.0
-	github.com/urfave/cli/v2 v2.27.2
+	github.com/stretchr/testify v1.10.0
+	github.com/urfave/cli/v2 v2.27.5
 )
 
 require (
-	github.com/cpuguy83/go-md2man/v2 v2.0.4 // indirect
+	github.com/cpuguy83/go-md2man/v2 v2.0.5 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/russross/blackfriday/v2 v2.1.0 // indirect
-	github.com/xrash/smetrics v0.0.0-20240312152122-5f08fbb34913 // indirect
+	github.com/xrash/smetrics v0.0.0-20240521201337-686a1a2994c1 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -1,5 +1,7 @@
 github.com/cpuguy83/go-md2man/v2 v2.0.4 h1:wfIWP927BUkWJb2NmU/kNDYIBTh/ziUX91+lVfRxZq4=
 github.com/cpuguy83/go-md2man/v2 v2.0.4/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
+github.com/cpuguy83/go-md2man/v2 v2.0.5 h1:ZtcqGrnekaHpVLArFSe4HK5DoKx1T0rq2DwVB0alcyc=
+github.com/cpuguy83/go-md2man/v2 v2.0.5/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
@@ -8,12 +10,14 @@ github.com/russross/blackfriday/v2 v2.1.0 h1:JIOH55/0cWyOuilr9/qlrm0BSXldqnqwMsf
 github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
 github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
 github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
-github.com/urfave/cli/v2 v2.27.1 h1:8xSQ6szndafKVRmfyeUMxkNUJQMjL1F2zmsZ+qHpfho=
-github.com/urfave/cli/v2 v2.27.1/go.mod h1:8qnjx1vcq5s2/wpsqoZFndg2CE5tNFyrTvS6SinrnYQ=
-github.com/urfave/cli/v2 v2.27.2 h1:6e0H+AkS+zDckwPCUrZkKX38mRaau4nL2uipkJpbkcI=
-github.com/urfave/cli/v2 v2.27.2/go.mod h1:g0+79LmHHATl7DAcHO99smiR/T7uGLw84w8Y42x+4eM=
-github.com/xrash/smetrics v0.0.0-20240312152122-5f08fbb34913 h1:+qGGcbkzsfDQNPPe9UDgpxAWQrhbbBXOYJFQDq/dtJw=
-github.com/xrash/smetrics v0.0.0-20240312152122-5f08fbb34913/go.mod h1:4aEEwZQutDLsQv2Deui4iYQ6DWTxR14g6m8Wv88+Xqk=
+github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOfJA=
+github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
+github.com/urfave/cli/v2 v2.27.4 h1:o1owoI+02Eb+K107p27wEX9Bb8eqIoZCfLXloLUSWJ8=
+github.com/urfave/cli/v2 v2.27.4/go.mod h1:m4QzxcD2qpra4z7WhzEGn74WZLViBnMpb1ToCAKdGRQ=
+github.com/urfave/cli/v2 v2.27.5 h1:WoHEJLdsXr6dDWoJgMq/CboDmyY/8HMMH1fTECbih+w=
+github.com/urfave/cli/v2 v2.27.5/go.mod h1:3Sevf16NykTbInEnD0yKkjDAeZDS0A6bzhBH5hrMvTQ=
+github.com/xrash/smetrics v0.0.0-20240521201337-686a1a2994c1 h1:gEOO8jv9F4OT7lGCjxCBTO/36wtF6j2nSip77qHd4x4=
+github.com/xrash/smetrics v0.0.0-20240521201337-686a1a2994c1/go.mod h1:Ohn+xnUBiLI6FVj/9LpzZWtj1/D6lUovWYBkxHVV3aM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=

internal/bracket/bracket.go

@@ -13,7 +13,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package file
+package bracket
 
 import (
 	F "github.com/IBM/fp-go/function"

internal/testing/sequence.go

@@ -143,3 +143,41 @@ func SequenceArrayErrorTest[
 		}
 	}
 }
+
+// SequenceRecordTest tests if the sequence operation works in case the operation cannot error
+func SequenceRecordTest[
+	HKTA,
+	HKTB,
+	HKTAA any, // HKT[map[string]string]
+](
+	eq EQ.Eq[HKTB],
+
+	pa pointed.Pointed[string, HKTA],
+	pb pointed.Pointed[bool, HKTB],
+	faa functor.Functor[map[string]string, bool, HKTAA, HKTB],
+	seq func(map[string]HKTA) HKTAA,
+) func(count int) func(t *testing.T) {
+
+	return func(count int) func(t *testing.T) {
+
+		exp := make(map[string]string)
+		good := make(map[string]HKTA)
+		for i := 0; i < count; i++ {
+			key := fmt.Sprintf("KeyData %d", i)
+			val := fmt.Sprintf("ValueData %d", i)
+			exp[key] = val
+			good[key] = pa.Of(val)
+		}
+
+		return func(t *testing.T) {
+			res := F.Pipe2(
+				good,
+				seq,
+				faa.Map(func(act map[string]string) bool {
+					return assert.Equal(t, exp, act)
+				}),
+			)
+			assert.True(t, eq.Equals(res, pb.Of(true)))
+		}
+	}
+}

option/record_test.go

@@ -16,21 +16,13 @@
 package option
 
 import (
+	"fmt"
 	"testing"
 
+	TST "github.com/IBM/fp-go/internal/testing"
 	"github.com/stretchr/testify/assert"
 )
 
-func TestSequenceRecord(t *testing.T) {
-	assert.Equal(t, Of(map[string]string{
-		"a": "A",
-		"b": "B",
-	}), SequenceRecord(map[string]Option[string]{
-		"a": Of("A"),
-		"b": Of("B"),
-	}))
-}
-
 func TestCompactRecord(t *testing.T) {
 	// make the map
 	m := make(map[string]Option[int])
@@ -45,3 +37,18 @@ func TestCompactRecord(t *testing.T) {
 
 	assert.Equal(t, exp, m1)
 }
+
+func TestSequenceRecord(t *testing.T) {
+
+	s := TST.SequenceRecordTest(
+		FromStrictEquals[bool](),
+		Pointed[string](),
+		Pointed[bool](),
+		Functor[map[string]string, bool](),
+		SequenceRecord[string, string],
+	)
+
+	for i := 0; i < 10; i++ {
+		t.Run(fmt.Sprintf("TestSequenceRecord %d", i), s(i))
+	}
+}

ord/ord.go

@@ -64,7 +64,7 @@ func Reverse[T any](o Ord[T]) Ord[T] {
 	}, o.Equals)
 }
 
-// Contramap creates an odering under a transformation function
+// Contramap creates an ordering under a transformation function
 func Contramap[A, B any](f func(B) A) func(Ord[A]) Ord[B] {
 	return func(o Ord[A]) Ord[B] {
 		return MakeOrd(func(x, y B) int {

record/eq.go

@@ -23,3 +23,8 @@ import (
 func Eq[K comparable, V any](e E.Eq[V]) E.Eq[map[K]V] {
 	return G.Eq[map[K]V, K, V](e)
 }
+
+// FromStrictEquals constructs an [EQ.Eq] from the canonical comparison function
+func FromStrictEquals[K, V comparable]() E.Eq[map[K]V] {
+	return G.FromStrictEquals[map[K]V]()
+}

record/eq_test.go

@@ -0,0 +1,48 @@
+// Copyright (c) 2024 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 record
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestFromStrictEquals(t *testing.T) {
+	m1 := map[string]string{
+		"a": "A",
+		"b": "B",
+	}
+	m2 := map[string]string{
+		"a": "A",
+		"b": "C",
+	}
+	m3 := map[string]string{
+		"a": "A",
+		"b": "B",
+	}
+	m4 := map[string]string{
+		"a": "A",
+		"b": "B",
+		"c": "C",
+	}
+
+	e := FromStrictEquals[string, string]()
+	assert.True(t, e.Equals(m1, m1))
+	assert.True(t, e.Equals(m1, m3))
+	assert.False(t, e.Equals(m1, m2))
+	assert.False(t, e.Equals(m1, m4))
+}

record/generic/eq.go

@@ -37,3 +37,8 @@ func Eq[M ~map[K]V, K comparable, V any](e E.Eq[V]) E.Eq[M] {
 		return equals(left, right, eq)
 	})
 }
+
+// FromStrictEquals constructs an [EQ.Eq] from the canonical comparison function
+func FromStrictEquals[M ~map[K]V, K, V comparable]() E.Eq[M] {
+	return Eq[M](E.FromStrictEquals[V]())
+}

record/monoid_test.go

@@ -54,3 +54,69 @@ func TestUnionMonoid(t *testing.T) {
 
 	assert.Equal(t, res, m.Concat(x, y))
 }
+
+func TestUnionFirstMonoid(t *testing.T) {
+	m := UnionFirstMonoid[string, string]()
+
+	e := Empty[string, string]()
+
+	x := map[string]string{
+		"a": "a1",
+		"b": "b1",
+		"c": "c1",
+	}
+
+	y := map[string]string{
+		"b": "b2",
+		"c": "c2",
+		"d": "d2",
+	}
+
+	res := map[string]string{
+		"a": "a1",
+		"b": "b1",
+		"c": "c1",
+		"d": "d2",
+	}
+
+	assert.Equal(t, x, m.Concat(x, m.Empty()))
+	assert.Equal(t, x, m.Concat(m.Empty(), x))
+
+	assert.Equal(t, x, m.Concat(x, e))
+	assert.Equal(t, x, m.Concat(e, x))
+
+	assert.Equal(t, res, m.Concat(x, y))
+}
+
+func TestUnionLastMonoid(t *testing.T) {
+	m := UnionLastMonoid[string, string]()
+
+	e := Empty[string, string]()
+
+	x := map[string]string{
+		"a": "a1",
+		"b": "b1",
+		"c": "c1",
+	}
+
+	y := map[string]string{
+		"b": "b2",
+		"c": "c2",
+		"d": "d2",
+	}
+
+	res := map[string]string{
+		"a": "a1",
+		"b": "b2",
+		"c": "c2",
+		"d": "d2",
+	}
+
+	assert.Equal(t, x, m.Concat(x, m.Empty()))
+	assert.Equal(t, x, m.Concat(m.Empty(), x))
+
+	assert.Equal(t, x, m.Concat(x, e))
+	assert.Equal(t, x, m.Concat(e, x))
+
+	assert.Equal(t, res, m.Concat(x, y))
+}

record/record_test.go

@@ -176,3 +176,25 @@ func TestFromArrayMap(t *testing.T) {
 		"C": "C",
 	}, res2)
 }
+
+func TestEmpty(t *testing.T) {
+	nonEmpty := map[string]string{
+		"a": "A",
+		"b": "B",
+	}
+	empty := Empty[string, string]()
+
+	assert.True(t, IsEmpty(empty))
+	assert.False(t, IsEmpty(nonEmpty))
+	assert.False(t, IsNonEmpty(empty))
+	assert.True(t, IsNonEmpty(nonEmpty))
+}
+
+func TestHas(t *testing.T) {
+	nonEmpty := map[string]string{
+		"a": "A",
+		"b": "B",
+	}
+	assert.True(t, Has("a", nonEmpty))
+	assert.False(t, Has("c", nonEmpty))
+}

v2/README.md

@@ -0,0 +1,43 @@
+# Functional programming library for golang V2
+
+Go 1.24 introduces [generic type aliases](https://github.com/golang/go/issues/46477) which are leveraged by V2.
+
+## ⚠️ Breaking Changes
+
+- use of [generic type aliases](https://github.com/golang/go/issues/46477) which requires [go1.24](https://tip.golang.org/doc/go1.24)
+- order of generic type arguments adjusted such that types that _cannot_ be inferred by the method argument come first, e.g. in the `Ap` methods
+- monadic operations for `Pair` operate on the second argument, to be compatible with the [Haskell](https://hackage.haskell.org/package/TypeCompose-0.9.14/docs/Data-Pair.html) definition
+
+## Simplifications
+
+- use type aliases to get rid of namespace imports for type declarations, e.g. instead of
+
+```go
+import (
+    ET "github.com/IBM/fp-go/v2/either"
+)
+
+func doSth() ET.Either[error, string] {
+    ...
+}
+```
+
+you can declare your type once 
+
+```go
+import (
+    "github.com/IBM/fp-go/v2/either"
+)
+
+type Either[A any] = either.Either[error, A]
+```
+
+and then use it across your codebase
+
+```go
+func doSth() Either[string] {
+    ...
+}
+```
+
+- library implementation does no longer need to use the `generic` subpackage, this simplifies reading and understanding of the code

v2/array/any.go

@@ -0,0 +1,30 @@
+// 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 array
+
+import (
+	G "github.com/IBM/fp-go/v2/array/generic"
+)
+
+// AnyWithIndex tests if any of the elements in the array matches the predicate
+func AnyWithIndex[A any](pred func(int, A) bool) func([]A) bool {
+	return G.AnyWithIndex[[]A](pred)
+}
+
+// Any tests if any of the elements in the array matches the predicate
+func Any[A any](pred func(A) bool) func([]A) bool {
+	return G.Any[[]A](pred)
+}

v2/array/any_test.go

@@ -0,0 +1,30 @@
+// 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 array
+
+import (
+	"testing"
+
+	F "github.com/IBM/fp-go/v2/function"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestAny(t *testing.T) {
+	anyBool := Any(F.Identity[bool])
+
+	assert.True(t, anyBool(From(false, true, false)))
+	assert.False(t, anyBool(From(false, false, false)))
+}

v2/array/array.go

@@ -0,0 +1,351 @@
+// 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 array
+
+import (
+	G "github.com/IBM/fp-go/v2/array/generic"
+	EM "github.com/IBM/fp-go/v2/endomorphism"
+	F "github.com/IBM/fp-go/v2/function"
+	"github.com/IBM/fp-go/v2/internal/array"
+	M "github.com/IBM/fp-go/v2/monoid"
+	O "github.com/IBM/fp-go/v2/option"
+	"github.com/IBM/fp-go/v2/tuple"
+)
+
+// From constructs an array from a set of variadic arguments
+func From[A any](data ...A) []A {
+	return G.From[[]A](data...)
+}
+
+// MakeBy returns a `Array` of length `n` with element `i` initialized with `f(i)`.
+func MakeBy[F ~func(int) A, A any](n int, f F) []A {
+	return G.MakeBy[[]A](n, f)
+}
+
+// Replicate creates a `Array` containing a value repeated the specified number of times.
+func Replicate[A any](n int, a A) []A {
+	return G.Replicate[[]A](n, a)
+}
+
+func MonadMap[A, B any](as []A, f func(a A) B) []B {
+	return G.MonadMap[[]A, []B](as, f)
+}
+
+func MonadMapRef[A, B any](as []A, f func(a *A) B) []B {
+	count := len(as)
+	bs := make([]B, count)
+	for i := count - 1; i >= 0; i-- {
+		bs[i] = f(&as[i])
+	}
+	return bs
+}
+
+func MapWithIndex[A, B any](f func(int, A) B) func([]A) []B {
+	return G.MapWithIndex[[]A, []B](f)
+}
+
+func Map[A, B any](f func(a A) B) func([]A) []B {
+	return G.Map[[]A, []B, A, B](f)
+}
+
+func MapRef[A, B any](f func(a *A) B) func([]A) []B {
+	return F.Bind2nd(MonadMapRef[A, B], f)
+}
+
+func filterRef[A any](fa []A, pred func(a *A) bool) []A {
+	var result []A
+	count := len(fa)
+	for i := 0; i < count; i++ {
+		a := fa[i]
+		if pred(&a) {
+			result = append(result, a)
+		}
+	}
+	return result
+}
+
+func filterMapRef[A, B any](fa []A, pred func(a *A) bool, f func(a *A) B) []B {
+	var result []B
+	count := len(fa)
+	for i := 0; i < count; i++ {
+		a := fa[i]
+		if pred(&a) {
+			result = append(result, f(&a))
+		}
+	}
+	return result
+}
+
+// Filter returns a new array with all elements from the original array that match a predicate
+func Filter[A any](pred func(A) bool) EM.Endomorphism[[]A] {
+	return G.Filter[[]A](pred)
+}
+
+// FilterWithIndex returns a new array with all elements from the original array that match a predicate
+func FilterWithIndex[A any](pred func(int, A) bool) EM.Endomorphism[[]A] {
+	return G.FilterWithIndex[[]A](pred)
+}
+
+func FilterRef[A any](pred func(*A) bool) EM.Endomorphism[[]A] {
+	return F.Bind2nd(filterRef[A], pred)
+}
+
+func MonadFilterMap[A, B any](fa []A, f func(A) O.Option[B]) []B {
+	return G.MonadFilterMap[[]A, []B](fa, f)
+}
+
+func MonadFilterMapWithIndex[A, B any](fa []A, f func(int, A) O.Option[B]) []B {
+	return G.MonadFilterMapWithIndex[[]A, []B](fa, f)
+}
+
+// FilterMap maps an array with an iterating function that returns an [O.Option] and it keeps only the Some values discarding the Nones.
+func FilterMap[A, B any](f func(A) O.Option[B]) func([]A) []B {
+	return G.FilterMap[[]A, []B](f)
+}
+
+// FilterMapWithIndex maps an array with an iterating function that returns an [O.Option] and it keeps only the Some values discarding the Nones.
+func FilterMapWithIndex[A, B any](f func(int, A) O.Option[B]) func([]A) []B {
+	return G.FilterMapWithIndex[[]A, []B](f)
+}
+
+// FilterChain maps an array with an iterating function that returns an [O.Option] of an array. It keeps only the Some values discarding the Nones and then flattens the result.
+func FilterChain[A, B any](f func(A) O.Option[[]B]) func([]A) []B {
+	return G.FilterChain[[]A](f)
+}
+
+func FilterMapRef[A, B any](pred func(a *A) bool, f func(a *A) B) func([]A) []B {
+	return func(fa []A) []B {
+		return filterMapRef(fa, pred, f)
+	}
+}
+
+func reduceRef[A, B any](fa []A, f func(B, *A) B, initial B) B {
+	current := initial
+	count := len(fa)
+	for i := 0; i < count; i++ {
+		current = f(current, &fa[i])
+	}
+	return current
+}
+
+func Reduce[A, B any](f func(B, A) B, initial B) func([]A) B {
+	return G.Reduce[[]A](f, initial)
+}
+
+func ReduceWithIndex[A, B any](f func(int, B, A) B, initial B) func([]A) B {
+	return G.ReduceWithIndex[[]A](f, initial)
+}
+
+func ReduceRight[A, B any](f func(A, B) B, initial B) func([]A) B {
+	return G.ReduceRight[[]A](f, initial)
+}
+
+func ReduceRightWithIndex[A, B any](f func(int, A, B) B, initial B) func([]A) B {
+	return G.ReduceRightWithIndex[[]A](f, initial)
+}
+
+func ReduceRef[A, B any](f func(B, *A) B, initial B) func([]A) B {
+	return func(as []A) B {
+		return reduceRef(as, f, initial)
+	}
+}
+
+func Append[A any](as []A, a A) []A {
+	return G.Append(as, a)
+}
+
+func IsEmpty[A any](as []A) bool {
+	return G.IsEmpty(as)
+}
+
+func IsNonEmpty[A any](as []A) bool {
+	return len(as) > 0
+}
+
+func Empty[A any]() []A {
+	return G.Empty[[]A]()
+}
+
+func Zero[A any]() []A {
+	return Empty[A]()
+}
+
+// Of constructs a single element array
+func Of[A any](a A) []A {
+	return G.Of[[]A](a)
+}
+
+func MonadChain[A, B any](fa []A, f func(a A) []B) []B {
+	return G.MonadChain[[]A, []B](fa, f)
+}
+
+func Chain[A, B any](f func(A) []B) func([]A) []B {
+	return G.Chain[[]A, []B](f)
+}
+
+func MonadAp[B, A any](fab []func(A) B, fa []A) []B {
+	return G.MonadAp[[]B](fab, fa)
+}
+
+func Ap[B, A any](fa []A) func([]func(A) B) []B {
+	return G.Ap[[]B, []func(A) B](fa)
+}
+
+func Match[A, B any](onEmpty func() B, onNonEmpty func([]A) B) func([]A) B {
+	return G.Match[[]A](onEmpty, onNonEmpty)
+}
+
+func MatchLeft[A, B any](onEmpty func() B, onNonEmpty func(A, []A) B) func([]A) B {
+	return G.MatchLeft[[]A](onEmpty, onNonEmpty)
+}
+
+func Tail[A any](as []A) O.Option[[]A] {
+	return G.Tail(as)
+}
+
+func Head[A any](as []A) O.Option[A] {
+	return G.Head(as)
+}
+
+func First[A any](as []A) O.Option[A] {
+	return G.First(as)
+}
+
+func Last[A any](as []A) O.Option[A] {
+	return G.Last(as)
+}
+
+func PrependAll[A any](middle A) EM.Endomorphism[[]A] {
+	return func(as []A) []A {
+		count := len(as)
+		dst := count * 2
+		result := make([]A, dst)
+		for i := count - 1; i >= 0; i-- {
+			dst--
+			result[dst] = as[i]
+			dst--
+			result[dst] = middle
+		}
+		return result
+	}
+}
+
+func Intersperse[A any](middle A) EM.Endomorphism[[]A] {
+	prepend := PrependAll(middle)
+	return func(as []A) []A {
+		if IsEmpty(as) {
+			return as
+		}
+		return prepend(as)[1:]
+	}
+}
+
+func Intercalate[A any](m M.Monoid[A]) func(A) func([]A) A {
+	concatAll := ConcatAll[A](m)
+	return func(middle A) func([]A) A {
+		return Match(m.Empty, F.Flow2(Intersperse(middle), concatAll))
+	}
+}
+
+func Flatten[A any](mma [][]A) []A {
+	return G.Flatten(mma)
+}
+
+func Slice[A any](low, high int) func(as []A) []A {
+	return array.Slice[[]A](low, high)
+}
+
+func Lookup[A any](idx int) func([]A) O.Option[A] {
+	return G.Lookup[[]A](idx)
+}
+
+func UpsertAt[A any](a A) EM.Endomorphism[[]A] {
+	return G.UpsertAt[[]A](a)
+}
+
+func Size[A any](as []A) int {
+	return G.Size(as)
+}
+
+func MonadPartition[A any](as []A, pred func(A) bool) tuple.Tuple2[[]A, []A] {
+	return G.MonadPartition(as, pred)
+}
+
+// Partition creates two new arrays out of one, the left result contains the elements
+// for which the predicate returns false, the right one those for which the predicate returns true
+func Partition[A any](pred func(A) bool) func([]A) tuple.Tuple2[[]A, []A] {
+	return G.Partition[[]A](pred)
+}
+
+// IsNil checks if the array is set to nil
+func IsNil[A any](as []A) bool {
+	return array.IsNil(as)
+}
+
+// IsNonNil checks if the array is set to nil
+func IsNonNil[A any](as []A) bool {
+	return array.IsNonNil(as)
+}
+
+// ConstNil returns a nil array
+func ConstNil[A any]() []A {
+	return array.ConstNil[[]A]()
+}
+
+func SliceRight[A any](start int) EM.Endomorphism[[]A] {
+	return G.SliceRight[[]A](start)
+}
+
+// Copy creates a shallow copy of the array
+func Copy[A any](b []A) []A {
+	return G.Copy(b)
+}
+
+// Clone creates a deep copy of the array using the provided endomorphism to clone the values
+func Clone[A any](f func(A) A) func(as []A) []A {
+	return G.Clone[[]A](f)
+}
+
+// FoldMap maps and folds an array. Map the Array passing each value to the iterating function. Then fold the results using the provided Monoid.
+func FoldMap[A, B any](m M.Monoid[B]) func(func(A) B) func([]A) B {
+	return G.FoldMap[[]A](m)
+}
+
+// FoldMapWithIndex maps and folds an array. Map the Array passing each value to the iterating function. Then fold the results using the provided Monoid.
+func FoldMapWithIndex[A, B any](m M.Monoid[B]) func(func(int, A) B) func([]A) B {
+	return G.FoldMapWithIndex[[]A](m)
+}
+
+// Fold folds the array using the provided Monoid.
+func Fold[A any](m M.Monoid[A]) func([]A) A {
+	return G.Fold[[]A](m)
+}
+
+func Push[A any](a A) EM.Endomorphism[[]A] {
+	return G.Push[EM.Endomorphism[[]A]](a)
+}
+
+func MonadFlap[B, A any](fab []func(A) B, a A) []B {
+	return G.MonadFlap[func(A) B, []func(A) B, []B, A, B](fab, a)
+}
+
+func Flap[B, A any](a A) func([]func(A) B) []B {
+	return G.Flap[func(A) B, []func(A) B, []B, A, B](a)
+}
+
+func Prepend[A any](head A) EM.Endomorphism[[]A] {
+	return G.Prepend[EM.Endomorphism[[]A]](head)
+}

v2/array/array_test.go

@@ -0,0 +1,205 @@
+// 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 array
+
+import (
+	"fmt"
+	"strings"
+	"testing"
+
+	F "github.com/IBM/fp-go/v2/function"
+	"github.com/IBM/fp-go/v2/internal/utils"
+	O "github.com/IBM/fp-go/v2/option"
+	S "github.com/IBM/fp-go/v2/string"
+	T "github.com/IBM/fp-go/v2/tuple"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestMap1(t *testing.T) {
+
+	src := []string{"a", "b", "c"}
+
+	up := Map(strings.ToUpper)(src)
+
+	var up1 = []string{}
+	for _, s := range src {
+		up1 = append(up1, strings.ToUpper(s))
+	}
+
+	var up2 = []string{}
+	for i := range src {
+		up2 = append(up2, strings.ToUpper(src[i]))
+	}
+
+	assert.Equal(t, up, up1)
+	assert.Equal(t, up, up2)
+}
+
+func TestMap(t *testing.T) {
+
+	mapper := Map(utils.Upper)
+
+	src := []string{"a", "b", "c"}
+
+	dst := mapper(src)
+
+	assert.Equal(t, dst, []string{"A", "B", "C"})
+}
+
+func TestReduceRight(t *testing.T) {
+	values := From("a", "b", "c")
+	f := func(a, acc string) string {
+		return fmt.Sprintf("%s%s", acc, a)
+	}
+	b := ""
+
+	assert.Equal(t, "cba", ReduceRight(f, b)(values))
+	assert.Equal(t, "", ReduceRight(f, b)(Empty[string]()))
+}
+
+func TestReduce(t *testing.T) {
+
+	values := MakeBy(101, F.Identity[int])
+
+	sum := func(val int, current int) int {
+		return val + current
+	}
+	reducer := Reduce(sum, 0)
+
+	result := reducer(values)
+	assert.Equal(t, result, 5050)
+
+}
+
+func TestEmpty(t *testing.T) {
+	assert.True(t, IsNonEmpty(MakeBy(101, F.Identity[int])))
+	assert.True(t, IsEmpty([]int{}))
+}
+
+func TestAp(t *testing.T) {
+	assert.Equal(t,
+		[]int{2, 4, 6, 3, 6, 9},
+		F.Pipe1(
+			[]func(int) int{
+				utils.Double,
+				utils.Triple,
+			},
+			Ap[int, int]([]int{1, 2, 3}),
+		),
+	)
+}
+
+func TestIntercalate(t *testing.T) {
+	is := Intercalate(S.Monoid)("-")
+
+	assert.Equal(t, "", is(Empty[string]()))
+	assert.Equal(t, "a", is([]string{"a"}))
+	assert.Equal(t, "a-b-c", is([]string{"a", "b", "c"}))
+	assert.Equal(t, "a--c", is([]string{"a", "", "c"}))
+	assert.Equal(t, "a-b", is([]string{"a", "b"}))
+	assert.Equal(t, "a-b-c-d", is([]string{"a", "b", "c", "d"}))
+}
+
+func TestPrependAll(t *testing.T) {
+	empty := Empty[int]()
+	prep := PrependAll(0)
+	assert.Equal(t, empty, prep(empty))
+	assert.Equal(t, []int{0, 1, 0, 2, 0, 3}, prep([]int{1, 2, 3}))
+	assert.Equal(t, []int{0, 1}, prep([]int{1}))
+	assert.Equal(t, []int{0, 1, 0, 2, 0, 3, 0, 4}, prep([]int{1, 2, 3, 4}))
+}
+
+func TestFlatten(t *testing.T) {
+	assert.Equal(t, []int{1, 2, 3}, Flatten([][]int{{1}, {2}, {3}}))
+}
+
+func TestLookup(t *testing.T) {
+	data := []int{0, 1, 2}
+	none := O.None[int]()
+
+	assert.Equal(t, none, Lookup[int](-1)(data))
+	assert.Equal(t, none, Lookup[int](10)(data))
+	assert.Equal(t, O.Some(1), Lookup[int](1)(data))
+}
+
+func TestSlice(t *testing.T) {
+	data := []int{0, 1, 2, 3}
+
+	assert.Equal(t, []int{1, 2}, Slice[int](1, 3)(data))
+}
+
+func TestFrom(t *testing.T) {
+	assert.Equal(t, []int{1, 2, 3}, From(1, 2, 3))
+}
+
+func TestPartition(t *testing.T) {
+
+	pred := func(n int) bool {
+		return n > 2
+	}
+
+	assert.Equal(t, T.MakeTuple2(Empty[int](), Empty[int]()), Partition(pred)(Empty[int]()))
+	assert.Equal(t, T.MakeTuple2(From(1), From(3)), Partition(pred)(From(1, 3)))
+}
+
+func TestFilterChain(t *testing.T) {
+	src := From(1, 2, 3)
+
+	f := func(i int) O.Option[[]string] {
+		if i%2 != 0 {
+			return O.Of(From(fmt.Sprintf("a%d", i), fmt.Sprintf("b%d", i)))
+		}
+		return O.None[[]string]()
+	}
+
+	res := FilterChain(f)(src)
+
+	assert.Equal(t, From("a1", "b1", "a3", "b3"), res)
+}
+
+func TestFilterMap(t *testing.T) {
+	src := From(1, 2, 3)
+
+	f := func(i int) O.Option[string] {
+		if i%2 != 0 {
+			return O.Of(fmt.Sprintf("a%d", i))
+		}
+		return O.None[string]()
+	}
+
+	res := FilterMap(f)(src)
+
+	assert.Equal(t, From("a1", "a3"), res)
+}
+
+func TestFoldMap(t *testing.T) {
+	src := From("a", "b", "c")
+
+	fold := FoldMap[string](S.Monoid)(strings.ToUpper)
+
+	assert.Equal(t, "ABC", fold(src))
+}
+
+func ExampleFoldMap() {
+	src := From("a", "b", "c")
+
+	fold := FoldMap[string](S.Monoid)(strings.ToUpper)
+
+	fmt.Println(fold(src))
+
+	// Output: ABC
+
+}

v2/array/bind.go

@@ -0,0 +1,66 @@
+// 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 array
+
+import (
+	G "github.com/IBM/fp-go/v2/array/generic"
+)
+
+// Bind creates an empty context of type [S] to be used with the [Bind] operation
+func Do[S any](
+	empty S,
+) []S {
+	return G.Do[[]S, S](empty)
+}
+
+// Bind attaches the result of a computation to a context [S1] to produce a context [S2]
+func Bind[S1, S2, T any](
+	setter func(T) func(S1) S2,
+	f func(S1) []T,
+) func([]S1) []S2 {
+	return G.Bind[[]S1, []S2, []T, S1, S2, T](setter, f)
+}
+
+// Let attaches the result of a computation to a context [S1] to produce a context [S2]
+func Let[S1, S2, T any](
+	setter func(T) func(S1) S2,
+	f func(S1) T,
+) func([]S1) []S2 {
+	return G.Let[[]S1, []S2, S1, S2, T](setter, f)
+}
+
+// LetTo attaches the a value to a context [S1] to produce a context [S2]
+func LetTo[S1, S2, T any](
+	setter func(T) func(S1) S2,
+	b T,
+) func([]S1) []S2 {
+	return G.LetTo[[]S1, []S2, S1, S2, T](setter, b)
+}
+
+// BindTo initializes a new state [S1] from a value [T]
+func BindTo[S1, T any](
+	setter func(T) S1,
+) func([]T) []S1 {
+	return G.BindTo[[]S1, []T, S1, T](setter)
+}
+
+// ApS attaches a value to a context [S1] to produce a context [S2] by considering the context and the value concurrently
+func ApS[S1, S2, T any](
+	setter func(T) func(S1) S2,
+	fa []T,
+) func([]S1) []S2 {
+	return G.ApS[[]S1, []S2, []T, S1, S2, T](setter, fa)
+}

v2/array/bind_test.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 array
+
+import (
+	"testing"
+
+	F "github.com/IBM/fp-go/v2/function"
+	"github.com/IBM/fp-go/v2/internal/utils"
+	"github.com/stretchr/testify/assert"
+)
+
+func getLastName(s utils.Initial) []string {
+	return Of("Doe")
+}
+
+func getGivenName(s utils.WithLastName) []string {
+	return Of("John")
+}
+
+func TestBind(t *testing.T) {
+
+	res := F.Pipe3(
+		Do(utils.Empty),
+		Bind(utils.SetLastName, getLastName),
+		Bind(utils.SetGivenName, getGivenName),
+		Map(utils.GetFullName),
+	)
+
+	assert.Equal(t, res, Of("John Doe"))
+}
+
+func TestApS(t *testing.T) {
+
+	res := F.Pipe3(
+		Do(utils.Empty),
+		ApS(utils.SetLastName, Of("Doe")),
+		ApS(utils.SetGivenName, Of("John")),
+		Map(utils.GetFullName),
+	)
+
+	assert.Equal(t, res, Of("John Doe"))
+}

v2/array/eq.go

@@ -0,0 +1,40 @@
+// Copyright (c) 2023 IBM Corp.
+// All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package array
+
+import (
+	E "github.com/IBM/fp-go/v2/eq"
+)
+
+func equals[T any](left []T, right []T, eq func(T, T) bool) bool {
+	if len(left) != len(right) {
+		return false
+	}
+	for i, v1 := range left {
+		v2 := right[i]
+		if !eq(v1, v2) {
+			return false
+		}
+	}
+	return true
+}
+
+func Eq[T any](e E.Eq[T]) E.Eq[[]T] {
+	eq := e.Equals
+	return E.FromEquals(func(left, right []T) bool {
+		return equals(left, right, eq)
+	})
+}

v2/array/example_any_test.go

@@ -0,0 +1,77 @@
+// 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 array
+
+import (
+	"fmt"
+
+	F "github.com/IBM/fp-go/v2/function"
+	O "github.com/IBM/fp-go/v2/option"
+)
+
+func Example_any() {
+
+	pred := func(val int) bool {
+		return val&2 == 0
+	}
+
+	data1 := From(1, 2, 3)
+
+	fmt.Println(Any(pred)(data1))
+
+	// Output:
+	// true
+}
+
+func Example_any_filter() {
+
+	pred := func(val int) bool {
+		return val&2 == 0
+	}
+
+	data1 := From(1, 2, 3)
+
+	// Any tests if any of the entries in the array matches the condition
+	Any := F.Flow2(
+		Filter(pred),
+		IsNonEmpty[int],
+	)
+
+	fmt.Println(Any(data1))
+
+	// Output:
+	// true
+}
+
+func Example_any_find() {
+
+	pred := func(val int) bool {
+		return val&2 == 0
+	}
+
+	data1 := From(1, 2, 3)
+
+	// Any tests if any of the entries in the array matches the condition
+	Any := F.Flow2(
+		FindFirst(pred),
+		O.IsSome[int],
+	)
+
+	fmt.Println(Any(data1))
+
+	// Output:
+	// true
+}

v2/array/example_find_test.go

@@ -0,0 +1,55 @@
+// 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 array
+
+import (
+	"fmt"
+
+	F "github.com/IBM/fp-go/v2/function"
+)
+
+func Example_find() {
+
+	pred := func(val int) bool {
+		return val&2 == 0
+	}
+
+	data1 := From(1, 2, 3)
+
+	fmt.Println(FindFirst(pred)(data1))
+
+	// Output:
+	// Some[int](1)
+}
+
+func Example_find_filter() {
+
+	pred := func(val int) bool {
+		return val&2 == 0
+	}
+
+	data1 := From(1, 2, 3)
+
+	Find := F.Flow2(
+		Filter(pred),
+		Head[int],
+	)
+
+	fmt.Println(Find(data1))
+
+	// Output:
+	// Some[int](1)
+}

v2/array/examples_basic_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 array
+
+import (
+	"fmt"
+
+	F "github.com/IBM/fp-go/v2/function"
+	O "github.com/IBM/fp-go/v2/option"
+)
+
+// Example_basic adapts examples from [https://github.com/inato/fp-ts-cheatsheet#basic-manipulation]
+func Example_basic() {
+
+	someArray := From(0, 1, 2, 3, 4, 5, 6, 7, 8, 9) // []int
+
+	isEven := func(num int) bool {
+		return num%2 == 0
+	}
+
+	square := func(num int) int {
+		return num * num
+	}
+
+	// filter and map
+	result := F.Pipe2(
+		someArray,
+		Filter(isEven),
+		Map(square),
+	) // [0 4 16 36 64]
+
+	// or in one go with filterMap
+	resultFilterMap := F.Pipe1(
+		someArray,
+		FilterMap(
+			F.Flow2(O.FromPredicate(isEven), O.Map(square)),
+		),
+	)
+
+	fmt.Println(result)
+	fmt.Println(resultFilterMap)
+
+	// Output:
+	// [0 4 16 36 64]
+	// [0 4 16 36 64]
+}

v2/array/examples_sort_test.go

@@ -0,0 +1,92 @@
+// 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 array
+
+import (
+	"fmt"
+
+	F "github.com/IBM/fp-go/v2/function"
+	I "github.com/IBM/fp-go/v2/number/integer"
+	O "github.com/IBM/fp-go/v2/option"
+	"github.com/IBM/fp-go/v2/ord"
+	S "github.com/IBM/fp-go/v2/string"
+)
+
+type user struct {
+	name string
+	age  O.Option[int]
+}
+
+func (user user) GetName() string {
+	return user.name
+}
+
+func (user user) GetAge() O.Option[int] {
+	return user.age
+}
+
+// Example_sort adapts examples from [https://github.com/inato/fp-ts-cheatsheet#sort-elements-with-ord]
+func Example_sort() {
+
+	strings := From("zyx", "abc", "klm")
+
+	sortedStrings := F.Pipe1(
+		strings,
+		Sort(S.Ord),
+	) // => ['abc', 'klm', 'zyx']
+
+	// reverse sort
+	reverseSortedStrings := F.Pipe1(
+		strings,
+		Sort(ord.Reverse(S.Ord)),
+	) // => ['zyx', 'klm', 'abc']
+
+	// sort Option
+	optionalNumbers := From(O.Some(1337), O.None[int](), O.Some(42))
+
+	sortedNums := F.Pipe1(
+		optionalNumbers,
+		Sort(O.Ord(I.Ord)),
+	)
+
+	// complex object with different rules
+	byName := F.Pipe1(
+		S.Ord,
+		ord.Contramap(user.GetName),
+	) // ord.Ord[user]
+
+	byAge := F.Pipe1(
+		O.Ord(I.Ord),
+		ord.Contramap(user.GetAge),
+	) // ord.Ord[user]
+
+	sortedUsers := F.Pipe1(
+		From(user{name: "a", age: O.Of(30)}, user{name: "d", age: O.Of(10)}, user{name: "c"}, user{name: "b", age: O.Of(10)}),
+		SortBy(From(byAge, byName)),
+	)
+
+	fmt.Println(sortedStrings)
+	fmt.Println(reverseSortedStrings)
+	fmt.Println(sortedNums)
+	fmt.Println(sortedUsers)
+
+	// Output:
+	// [abc klm zyx]
+	// [zyx klm abc]
+	// [None[int] Some[int](42) Some[int](1337)]
+	// [{c {false 0}} {b {true 10}} {d {true 10}} {a {true 30}}]
+
+}

v2/array/find.go

@@ -0,0 +1,61 @@
+// 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 array
+
+import (
+	G "github.com/IBM/fp-go/v2/array/generic"
+	O "github.com/IBM/fp-go/v2/option"
+)
+
+// FindFirst finds the first element which satisfies a predicate (or a refinement) function
+func FindFirst[A any](pred func(A) bool) func([]A) O.Option[A] {
+	return G.FindFirst[[]A](pred)
+}
+
+// FindFirstWithIndex finds the first element which satisfies a predicate (or a refinement) function
+func FindFirstWithIndex[A any](pred func(int, A) bool) func([]A) O.Option[A] {
+	return G.FindFirstWithIndex[[]A](pred)
+}
+
+// FindFirstMap finds the first element returned by an [O.Option] based selector function
+func FindFirstMap[A, B any](sel func(A) O.Option[B]) func([]A) O.Option[B] {
+	return G.FindFirstMap[[]A](sel)
+}
+
+// FindFirstMapWithIndex finds the first element returned by an [O.Option] based selector function
+func FindFirstMapWithIndex[A, B any](sel func(int, A) O.Option[B]) func([]A) O.Option[B] {
+	return G.FindFirstMapWithIndex[[]A](sel)
+}
+
+// FindLast finds the Last element which satisfies a predicate (or a refinement) function
+func FindLast[A any](pred func(A) bool) func([]A) O.Option[A] {
+	return G.FindLast[[]A](pred)
+}
+
+// FindLastWithIndex finds the Last element which satisfies a predicate (or a refinement) function
+func FindLastWithIndex[A any](pred func(int, A) bool) func([]A) O.Option[A] {
+	return G.FindLastWithIndex[[]A](pred)
+}
+
+// FindLastMap finds the Last element returned by an [O.Option] based selector function
+func FindLastMap[A, B any](sel func(A) O.Option[B]) func([]A) O.Option[B] {
+	return G.FindLastMap[[]A](sel)
+}
+
+// FindLastMapWithIndex finds the Last element returned by an [O.Option] based selector function
+func FindLastMapWithIndex[A, B any](sel func(int, A) O.Option[B]) func([]A) O.Option[B] {
+	return G.FindLastMapWithIndex[[]A](sel)
+}

v2/array/generic/any.go

@@ -0,0 +1,34 @@
+// 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 (
+	F "github.com/IBM/fp-go/v2/function"
+	O "github.com/IBM/fp-go/v2/option"
+)
+
+// AnyWithIndex tests if any of the elements in the array matches the predicate
+func AnyWithIndex[AS ~[]A, PRED ~func(int, A) bool, A any](pred PRED) func(AS) bool {
+	return F.Flow2(
+		FindFirstWithIndex[AS](pred),
+		O.IsSome[A],
+	)
+}
+
+// Any tests if any of the elements in the array matches the predicate
+func Any[AS ~[]A, PRED ~func(A) bool, A any](pred PRED) func(AS) bool {
+	return AnyWithIndex[AS](F.Ignore1of2[int](pred))
+}

v2/array/generic/array.go

@@ -0,0 +1,352 @@
+// 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 (
+	F "github.com/IBM/fp-go/v2/function"
+	"github.com/IBM/fp-go/v2/internal/array"
+	FC "github.com/IBM/fp-go/v2/internal/functor"
+	M "github.com/IBM/fp-go/v2/monoid"
+	O "github.com/IBM/fp-go/v2/option"
+	"github.com/IBM/fp-go/v2/tuple"
+)
+
+// Of constructs a single element array
+func Of[GA ~[]A, A any](value A) GA {
+	return GA{value}
+}
+
+func Reduce[GA ~[]A, A, B any](f func(B, A) B, initial B) func(GA) B {
+	return func(as GA) B {
+		return MonadReduce[GA](as, f, initial)
+	}
+}
+
+func ReduceWithIndex[GA ~[]A, A, B any](f func(int, B, A) B, initial B) func(GA) B {
+	return func(as GA) B {
+		return MonadReduceWithIndex[GA](as, f, initial)
+	}
+}
+
+func ReduceRight[GA ~[]A, A, B any](f func(A, B) B, initial B) func(GA) B {
+	return func(as GA) B {
+		return MonadReduceRight[GA](as, f, initial)
+	}
+}
+
+func ReduceRightWithIndex[GA ~[]A, A, B any](f func(int, A, B) B, initial B) func(GA) B {
+	return func(as GA) B {
+		return MonadReduceRightWithIndex[GA](as, f, initial)
+	}
+}
+
+func MonadReduce[GA ~[]A, A, B any](fa GA, f func(B, A) B, initial B) B {
+	return array.Reduce(fa, f, initial)
+}
+
+func MonadReduceWithIndex[GA ~[]A, A, B any](fa GA, f func(int, B, A) B, initial B) B {
+	return array.ReduceWithIndex(fa, f, initial)
+}
+
+func MonadReduceRight[GA ~[]A, A, B any](fa GA, f func(A, B) B, initial B) B {
+	return array.ReduceRight(fa, f, initial)
+}
+
+func MonadReduceRightWithIndex[GA ~[]A, A, B any](fa GA, f func(int, A, B) B, initial B) B {
+	return array.ReduceRightWithIndex(fa, f, initial)
+}
+
+// From constructs an array from a set of variadic arguments
+func From[GA ~[]A, A any](data ...A) GA {
+	return data
+}
+
+// MakeBy returns a `Array` of length `n` with element `i` initialized with `f(i)`.
+func MakeBy[AS ~[]A, F ~func(int) A, A any](n int, f F) AS {
+	// sanity check
+	if n <= 0 {
+		return Empty[AS]()
+	}
+	// run the generator function across the input
+	as := make(AS, n)
+	for i := n - 1; i >= 0; i-- {
+		as[i] = f(i)
+	}
+	return as
+}
+
+func Replicate[AS ~[]A, A any](n int, a A) AS {
+	return MakeBy[AS](n, F.Constant1[int](a))
+}
+
+func Lookup[GA ~[]A, A any](idx int) func(GA) O.Option[A] {
+	none := O.None[A]()
+	if idx < 0 {
+		return F.Constant1[GA](none)
+	}
+	return func(as GA) O.Option[A] {
+		if idx < len(as) {
+			return O.Some(as[idx])
+		}
+		return none
+	}
+}
+
+func Tail[GA ~[]A, A any](as GA) O.Option[GA] {
+	if array.IsEmpty(as) {
+		return O.None[GA]()
+	}
+	return O.Some(as[1:])
+}
+
+func Head[GA ~[]A, A any](as GA) O.Option[A] {
+	if array.IsEmpty(as) {
+		return O.None[A]()
+	}
+	return O.Some(as[0])
+}
+
+func First[GA ~[]A, A any](as GA) O.Option[A] {
+	return Head(as)
+}
+
+func Last[GA ~[]A, A any](as GA) O.Option[A] {
+	if array.IsEmpty(as) {
+		return O.None[A]()
+	}
+	return O.Some(as[len(as)-1])
+}
+
+func Append[GA ~[]A, A any](as GA, a A) GA {
+	return array.Append(as, a)
+}
+
+func Empty[GA ~[]A, A any]() GA {
+	return array.Empty[GA]()
+}
+
+func UpsertAt[GA ~[]A, A any](a A) func(GA) GA {
+	return array.UpsertAt[GA](a)
+}
+
+func MonadMap[GA ~[]A, GB ~[]B, A, B any](as GA, f func(a A) B) GB {
+	return array.MonadMap[GA, GB](as, f)
+}
+
+func Map[GA ~[]A, GB ~[]B, A, B any](f func(a A) B) func(GA) GB {
+	return array.Map[GA, GB](f)
+}
+
+func MonadMapWithIndex[GA ~[]A, GB ~[]B, A, B any](as GA, f func(int, A) B) GB {
+	return array.MonadMapWithIndex[GA, GB](as, f)
+}
+
+func MapWithIndex[GA ~[]A, GB ~[]B, A, B any](f func(int, A) B) func(GA) GB {
+	return F.Bind2nd(MonadMapWithIndex[GA, GB, A, B], f)
+}
+
+func Size[GA ~[]A, A any](as GA) int {
+	return len(as)
+}
+
+func filterMap[GA ~[]A, GB ~[]B, A, B any](fa GA, f func(A) O.Option[B]) GB {
+	return array.Reduce(fa, func(bs GB, a A) GB {
+		return O.MonadFold(f(a), F.Constant(bs), F.Bind1st(Append[GB, B], bs))
+	}, Empty[GB]())
+}
+
+func filterMapWithIndex[GA ~[]A, GB ~[]B, A, B any](fa GA, f func(int, A) O.Option[B]) GB {
+	return array.ReduceWithIndex(fa, func(idx int, bs GB, a A) GB {
+		return O.MonadFold(f(idx, a), F.Constant(bs), F.Bind1st(Append[GB, B], bs))
+	}, Empty[GB]())
+}
+
+func MonadFilterMap[GA ~[]A, GB ~[]B, A, B any](fa GA, f func(A) O.Option[B]) GB {
+	return filterMap[GA, GB](fa, f)
+}
+
+func MonadFilterMapWithIndex[GA ~[]A, GB ~[]B, A, B any](fa GA, f func(int, A) O.Option[B]) GB {
+	return filterMapWithIndex[GA, GB](fa, f)
+}
+
+func filterWithIndex[AS ~[]A, PRED ~func(int, A) bool, A any](fa AS, pred PRED) AS {
+	result := make(AS, 0, len(fa))
+	for i, a := range fa {
+		if pred(i, a) {
+			result = append(result, a)
+		}
+	}
+	return result
+}
+
+func FilterWithIndex[AS ~[]A, PRED ~func(int, A) bool, A any](pred PRED) func(AS) AS {
+	return F.Bind2nd(filterWithIndex[AS, PRED, A], pred)
+}
+
+func Filter[AS ~[]A, PRED ~func(A) bool, A any](pred PRED) func(AS) AS {
+	return FilterWithIndex[AS](F.Ignore1of2[int](pred))
+}
+
+func FilterChain[GA ~[]A, GB ~[]B, A, B any](f func(a A) O.Option[GB]) func(GA) GB {
+	return F.Flow2(
+		FilterMap[GA, []GB](f),
+		Flatten[[]GB],
+	)
+}
+
+func Flatten[GAA ~[]GA, GA ~[]A, A any](mma GAA) GA {
+	return MonadChain(mma, F.Identity[GA])
+}
+
+func FilterMap[GA ~[]A, GB ~[]B, A, B any](f func(A) O.Option[B]) func(GA) GB {
+	return F.Bind2nd(MonadFilterMap[GA, GB, A, B], f)
+}
+
+func FilterMapWithIndex[GA ~[]A, GB ~[]B, A, B any](f func(int, A) O.Option[B]) func(GA) GB {
+	return F.Bind2nd(MonadFilterMapWithIndex[GA, GB, A, B], f)
+}
+
+func MonadPartition[GA ~[]A, A any](as GA, pred func(A) bool) tuple.Tuple2[GA, GA] {
+	left := Empty[GA]()
+	right := Empty[GA]()
+	array.Reduce(as, func(c bool, a A) bool {
+		if pred(a) {
+			right = append(right, a)
+		} else {
+			left = append(left, a)
+		}
+		return c
+	}, true)
+	// returns the partition
+	return tuple.MakeTuple2(left, right)
+}
+
+func Partition[GA ~[]A, A any](pred func(A) bool) func(GA) tuple.Tuple2[GA, GA] {
+	return F.Bind2nd(MonadPartition[GA, A], pred)
+}
+
+func MonadChain[AS ~[]A, BS ~[]B, A, B any](fa AS, f func(a A) BS) BS {
+	return array.Reduce(fa, func(bs BS, a A) BS {
+		return append(bs, f(a)...)
+	}, Empty[BS]())
+}
+
+func Chain[AS ~[]A, BS ~[]B, A, B any](f func(A) BS) func(AS) BS {
+	return F.Bind2nd(MonadChain[AS, BS, A, B], f)
+}
+
+func MonadAp[BS ~[]B, ABS ~[]func(A) B, AS ~[]A, B, A any](fab ABS, fa AS) BS {
+	return MonadChain(fab, F.Bind1st(MonadMap[AS, BS, A, B], fa))
+}
+
+func Ap[BS ~[]B, ABS ~[]func(A) B, AS ~[]A, B, A any](fa AS) func(ABS) BS {
+	return F.Bind2nd(MonadAp[BS, ABS, AS], fa)
+}
+
+func IsEmpty[AS ~[]A, A any](as AS) bool {
+	return array.IsEmpty(as)
+}
+
+func IsNil[GA ~[]A, A any](as GA) bool {
+	return array.IsNil(as)
+}
+
+func IsNonNil[GA ~[]A, A any](as GA) bool {
+	return array.IsNonNil(as)
+}
+
+func Match[AS ~[]A, A, B any](onEmpty func() B, onNonEmpty func(AS) B) func(AS) B {
+	return func(as AS) B {
+		if IsEmpty(as) {
+			return onEmpty()
+		}
+		return onNonEmpty(as)
+	}
+}
+
+func MatchLeft[AS ~[]A, A, B any](onEmpty func() B, onNonEmpty func(A, AS) B) func(AS) B {
+	return func(as AS) B {
+		if IsEmpty(as) {
+			return onEmpty()
+		}
+		return onNonEmpty(as[0], as[1:])
+	}
+}
+
+func Slice[AS ~[]A, A any](start int, end int) func(AS) AS {
+	return func(a AS) AS {
+		return a[start:end]
+	}
+}
+
+func SliceRight[AS ~[]A, A any](start int) func(AS) AS {
+	return func(a AS) AS {
+		return a[start:]
+	}
+}
+
+func Copy[AS ~[]A, A any](b AS) AS {
+	buf := make(AS, len(b))
+	copy(buf, b)
+	return buf
+}
+
+func Clone[AS ~[]A, A any](f func(A) A) func(as AS) AS {
+	// implementation assumes that map does not optimize for the empty array
+	return Map[AS, AS](f)
+}
+
+func FoldMap[AS ~[]A, A, B any](m M.Monoid[B]) func(func(A) B) func(AS) B {
+	return func(f func(A) B) func(AS) B {
+		return func(as AS) B {
+			return array.Reduce(as, func(cur B, a A) B {
+				return m.Concat(cur, f(a))
+			}, m.Empty())
+		}
+	}
+}
+
+func FoldMapWithIndex[AS ~[]A, A, B any](m M.Monoid[B]) func(func(int, A) B) func(AS) B {
+	return func(f func(int, A) B) func(AS) B {
+		return func(as AS) B {
+			return array.ReduceWithIndex(as, func(idx int, cur B, a A) B {
+				return m.Concat(cur, f(idx, a))
+			}, m.Empty())
+		}
+	}
+}
+
+func Fold[AS ~[]A, A any](m M.Monoid[A]) func(AS) A {
+	return func(as AS) A {
+		return array.Reduce(as, m.Concat, m.Empty())
+	}
+}
+
+func Push[ENDO ~func(GA) GA, GA ~[]A, A any](a A) ENDO {
+	return F.Bind2nd(array.Push[GA, A], a)
+}
+
+func MonadFlap[FAB ~func(A) B, GFAB ~[]FAB, GB ~[]B, A, B any](fab GFAB, a A) GB {
+	return FC.MonadFlap(MonadMap[GFAB, GB], fab, a)
+}
+
+func Flap[FAB ~func(A) B, GFAB ~[]FAB, GB ~[]B, A, B any](a A) func(GFAB) GB {
+	return FC.Flap(Map[GFAB, GB], a)
+}
+
+func Prepend[ENDO ~func(AS) AS, AS []A, A any](head A) ENDO {
+	return array.Prepend[ENDO](head)
+}

v2/array/generic/bind.go

@@ -0,0 +1,89 @@
+// 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 (
+	A "github.com/IBM/fp-go/v2/internal/apply"
+	C "github.com/IBM/fp-go/v2/internal/chain"
+	F "github.com/IBM/fp-go/v2/internal/functor"
+)
+
+// Bind creates an empty context of type [S] to be used with the [Bind] operation
+func Do[GS ~[]S, S any](
+	empty S,
+) GS {
+	return Of[GS](empty)
+}
+
+// Bind attaches the result of a computation to a context [S1] to produce a context [S2]
+func Bind[GS1 ~[]S1, GS2 ~[]S2, GT ~[]T, S1, S2, T any](
+	setter func(T) func(S1) S2,
+	f func(S1) GT,
+) func(GS1) GS2 {
+	return C.Bind(
+		Chain[GS1, GS2, S1, S2],
+		Map[GT, GS2, T, S2],
+		setter,
+		f,
+	)
+}
+
+// Let attaches the result of a computation to a context [S1] to produce a context [S2]
+func Let[GS1 ~[]S1, GS2 ~[]S2, S1, S2, T any](
+	key func(T) func(S1) S2,
+	f func(S1) T,
+) func(GS1) GS2 {
+	return F.Let(
+		Map[GS1, GS2, S1, S2],
+		key,
+		f,
+	)
+}
+
+// LetTo attaches the a value to a context [S1] to produce a context [S2]
+func LetTo[GS1 ~[]S1, GS2 ~[]S2, S1, S2, B any](
+	key func(B) func(S1) S2,
+	b B,
+) func(GS1) GS2 {
+	return F.LetTo(
+		Map[GS1, GS2, S1, S2],
+		key,
+		b,
+	)
+}
+
+// BindTo initializes a new state [S1] from a value [T]
+func BindTo[GS1 ~[]S1, GT ~[]T, S1, T any](
+	setter func(T) S1,
+) func(GT) GS1 {
+	return C.BindTo(
+		Map[GT, GS1, T, S1],
+		setter,
+	)
+}
+
+// ApS attaches a value to a context [S1] to produce a context [S2] by considering the context and the value concurrently
+func ApS[GS1 ~[]S1, GS2 ~[]S2, GT ~[]T, S1, S2, T any](
+	setter func(T) func(S1) S2,
+	fa GT,
+) func(GS1) GS2 {
+	return A.ApS(
+		Ap[GS2, []func(T) S2, GT, S2, T],
+		Map[GS1, []func(T) S2, S1, func(T) S2],
+		setter,
+		fa,
+	)
+}

v2/array/generic/find.go

@@ -0,0 +1,97 @@
+// 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 (
+	F "github.com/IBM/fp-go/v2/function"
+	O "github.com/IBM/fp-go/v2/option"
+)
+
+// FindFirstWithIndex finds the first element which satisfies a predicate (or a refinement) function
+func FindFirstWithIndex[AS ~[]A, PRED ~func(int, A) bool, A any](pred PRED) func(AS) O.Option[A] {
+	none := O.None[A]()
+	return func(as AS) O.Option[A] {
+		for i, a := range as {
+			if pred(i, a) {
+				return O.Some(a)
+			}
+		}
+		return none
+	}
+}
+
+// FindFirst finds the first element which satisfies a predicate (or a refinement) function
+func FindFirst[AS ~[]A, PRED ~func(A) bool, A any](pred PRED) func(AS) O.Option[A] {
+	return FindFirstWithIndex[AS](F.Ignore1of2[int](pred))
+}
+
+// FindFirstMapWithIndex finds the first element returned by an [O.Option] based selector function
+func FindFirstMapWithIndex[AS ~[]A, PRED ~func(int, A) O.Option[B], A, B any](pred PRED) func(AS) O.Option[B] {
+	none := O.None[B]()
+	return func(as AS) O.Option[B] {
+		count := len(as)
+		for i := 0; i < count; i++ {
+			out := pred(i, as[i])
+			if O.IsSome(out) {
+				return out
+			}
+		}
+		return none
+	}
+}
+
+// FindFirstMap finds the first element returned by an [O.Option] based selector function
+func FindFirstMap[AS ~[]A, PRED ~func(A) O.Option[B], A, B any](pred PRED) func(AS) O.Option[B] {
+	return FindFirstMapWithIndex[AS](F.Ignore1of2[int](pred))
+}
+
+// FindLastWithIndex finds the first element which satisfies a predicate (or a refinement) function
+func FindLastWithIndex[AS ~[]A, PRED ~func(int, A) bool, A any](pred PRED) func(AS) O.Option[A] {
+	none := O.None[A]()
+	return func(as AS) O.Option[A] {
+		for i := len(as) - 1; i >= 0; i-- {
+			a := as[i]
+			if pred(i, a) {
+				return O.Some(a)
+			}
+		}
+		return none
+	}
+}
+
+// FindLast finds the first element which satisfies a predicate (or a refinement) function
+func FindLast[AS ~[]A, PRED ~func(A) bool, A any](pred PRED) func(AS) O.Option[A] {
+	return FindLastWithIndex[AS](F.Ignore1of2[int](pred))
+}
+
+// FindLastMapWithIndex finds the first element returned by an [O.Option] based selector function
+func FindLastMapWithIndex[AS ~[]A, PRED ~func(int, A) O.Option[B], A, B any](pred PRED) func(AS) O.Option[B] {
+	none := O.None[B]()
+	return func(as AS) O.Option[B] {
+		for i := len(as) - 1; i >= 0; i-- {
+			out := pred(i, as[i])
+			if O.IsSome(out) {
+				return out
+			}
+		}
+		return none
+	}
+}
+
+// FindLastMap finds the first element returned by an [O.Option] based selector function
+func FindLastMap[AS ~[]A, PRED ~func(A) O.Option[B], A, B any](pred PRED) func(AS) O.Option[B] {
+	return FindLastMapWithIndex[AS](F.Ignore1of2[int](pred))
+}

v2/array/generic/monad.go

@@ -0,0 +1,43 @@
+// Copyright (c) 2024 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 (
+	"github.com/IBM/fp-go/v2/internal/monad"
+)
+
+type arrayMonad[A, B any, GA ~[]A, GB ~[]B, GAB ~[]func(A) B] struct{}
+
+func (o *arrayMonad[A, B, GA, GB, GAB]) Of(a A) GA {
+	return Of[GA, A](a)
+}
+
+func (o *arrayMonad[A, B, GA, GB, GAB]) Map(f func(A) B) func(GA) GB {
+	return Map[GA, GB, A, B](f)
+}
+
+func (o *arrayMonad[A, B, GA, GB, GAB]) Chain(f func(A) GB) func(GA) GB {
+	return Chain[GA, GB, A, B](f)
+}
+
+func (o *arrayMonad[A, B, GA, GB, GAB]) Ap(fa GA) func(GAB) GB {
+	return Ap[GB, GAB, GA, B, A](fa)
+}
+
+// Monad implements the monadic operations for an array
+func Monad[A, B any, GA ~[]A, GB ~[]B, GAB ~[]func(A) B]() monad.Monad[A, B, GA, GB, GAB] {
+	return &arrayMonad[A, B, GA, GB, GAB]{}
+}

v2/array/generic/sort.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 (
+	"sort"
+
+	F "github.com/IBM/fp-go/v2/function"
+	O "github.com/IBM/fp-go/v2/ord"
+)
+
+// Sort implements a stable sort on the array given the provided ordering
+func Sort[GA ~[]T, T any](ord O.Ord[T]) func(ma GA) GA {
+	return SortByKey[GA](ord, F.Identity[T])
+}
+
+// SortByKey implements a stable sort on the array given the provided ordering on an extracted key
+func SortByKey[GA ~[]T, K, T any](ord O.Ord[K], f func(T) K) func(ma GA) GA {
+
+	return func(ma GA) GA {
+		// nothing to sort
+		l := len(ma)
+		if l < 2 {
+			return ma
+		}
+		// copy
+		cpy := make(GA, l)
+		copy(cpy, ma)
+		sort.Slice(cpy, func(i, j int) bool {
+			return ord.Compare(f(cpy[i]), f(cpy[j])) < 0
+		})
+		return cpy
+	}
+}
+
+// SortBy implements a stable sort on the array given the provided ordering
+func SortBy[GA ~[]T, GO ~[]O.Ord[T], T any](ord GO) func(ma GA) GA {
+	return F.Pipe2(
+		ord,
+		Fold[GO](O.Monoid[T]()),
+		Sort[GA, T],
+	)
+}

v2/array/generic/uniq.go

@@ -0,0 +1,32 @@
+package generic
+
+import F "github.com/IBM/fp-go/v2/function"
+
+// StrictUniq converts an array of arbitrary items into an array or unique items
+// where uniqueness is determined by the built-in uniqueness constraint
+func StrictUniq[AS ~[]A, A comparable](as AS) AS {
+	return Uniq[AS](F.Identity[A])(as)
+}
+
+// uniquePredUnsafe returns a predicate on a map for uniqueness
+func uniquePredUnsafe[PRED ~func(A) K, A any, K comparable](f PRED) func(int, A) bool {
+	lookup := make(map[K]bool)
+	return func(_ int, a A) bool {
+		k := f(a)
+		_, has := lookup[k]
+		if has {
+			return false
+		}
+		lookup[k] = true
+		return true
+	}
+}
+
+// Uniq converts an array of arbitrary items into an array or unique items
+// where uniqueness is determined based on a key extractor function
+func Uniq[AS ~[]A, PRED ~func(A) K, A any, K comparable](f PRED) func(as AS) AS {
+	return func(as AS) AS {
+		// we need to create a new predicate for each iteration
+		return filterWithIndex(as, uniquePredUnsafe(f))
+	}
+}

v2/array/generic/zip.go

@@ -0,0 +1,52 @@
+// 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 (
+	F "github.com/IBM/fp-go/v2/function"
+	N "github.com/IBM/fp-go/v2/number"
+	T "github.com/IBM/fp-go/v2/tuple"
+)
+
+// ZipWith applies a function to pairs of elements at the same index in two arrays, collecting the results in a new array. If one
+// input array is short, excess elements of the longer array are discarded.
+func ZipWith[AS ~[]A, BS ~[]B, CS ~[]C, FCT ~func(A, B) C, A, B, C any](fa AS, fb BS, f FCT) CS {
+	l := N.Min(len(fa), len(fb))
+	res := make(CS, l)
+	for i := l - 1; i >= 0; i-- {
+		res[i] = f(fa[i], fb[i])
+	}
+	return res
+}
+
+// Zip takes two arrays and returns an array of corresponding pairs. If one input array is short, excess elements of the
+// longer array are discarded
+func Zip[AS ~[]A, BS ~[]B, CS ~[]T.Tuple2[A, B], A, B any](fb BS) func(AS) CS {
+	return F.Bind23of3(ZipWith[AS, BS, CS, func(A, B) T.Tuple2[A, B]])(fb, T.MakeTuple2[A, B])
+}
+
+// Unzip is the function is reverse of [Zip]. Takes an array of pairs and return two corresponding arrays
+func Unzip[AS ~[]A, BS ~[]B, CS ~[]T.Tuple2[A, B], A, B any](cs CS) T.Tuple2[AS, BS] {
+	l := len(cs)
+	as := make(AS, l)
+	bs := make(BS, l)
+	for i := l - 1; i >= 0; i-- {
+		t := cs[i]
+		as[i] = t.F1
+		bs[i] = t.F2
+	}
+	return T.MakeTuple2(as, bs)
+}

v2/array/magma.go

@@ -0,0 +1,24 @@
+// 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 array
+
+import (
+	M "github.com/IBM/fp-go/v2/monoid"
+)
+
+func ConcatAll[A any](m M.Monoid[A]) func([]A) A {
+	return Reduce(m.Concat, m.Empty())
+}

v2/array/magma_test.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 array
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	M "github.com/IBM/fp-go/v2/monoid"
+)
+
+var subInt = M.MakeMonoid(func(first int, second int) int {
+	return first - second
+}, 0)
+
+func TestConcatAll(t *testing.T) {
+
+	var subAll = ConcatAll(subInt)
+
+	assert.Equal(t, subAll([]int{1, 2, 3}), -6)
+
+}

v2/array/monad.go

@@ -0,0 +1,26 @@
+// Copyright (c) 2024 IBM Corp.
+// All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package array
+
+import (
+	G "github.com/IBM/fp-go/v2/array/generic"
+	"github.com/IBM/fp-go/v2/internal/monad"
+)
+
+// Monad returns the monadic operations for an array
+func Monad[A, B any]() monad.Monad[A, B, []A, []B, []func(A) B] {
+	return G.Monad[A, B, []A, []B, []func(A) B]()
+}

v2/array/monoid.go

@@ -0,0 +1,63 @@
+// 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 array
+
+import (
+	"github.com/IBM/fp-go/v2/internal/array"
+	M "github.com/IBM/fp-go/v2/monoid"
+	S "github.com/IBM/fp-go/v2/semigroup"
+)
+
+func concat[T any](left, right []T) []T {
+	// some performance checks
+	ll := len(left)
+	if ll == 0 {
+		return right
+	}
+	lr := len(right)
+	if lr == 0 {
+		return left
+	}
+	// need to copy
+	buf := make([]T, ll+lr)
+	copy(buf[copy(buf, left):], right)
+	return buf
+}
+
+func Monoid[T any]() M.Monoid[[]T] {
+	return M.MakeMonoid(concat[T], Empty[T]())
+}
+
+func Semigroup[T any]() S.Semigroup[[]T] {
+	return S.MakeSemigroup(concat[T])
+}
+
+func addLen[A any](count int, data []A) int {
+	return count + len(data)
+}
+
+// ConcatAll efficiently concatenates the input arrays into a final array
+func ArrayConcatAll[A any](data ...[]A) []A {
+	// get the full size
+	count := array.Reduce(data, addLen[A], 0)
+	buf := make([]A, count)
+	// copy
+	array.Reduce(data, func(idx int, seg []A) int {
+		return idx + copy(buf[idx:], seg)
+	}, 0)
+	// returns the final array
+	return buf
+}

v2/array/monoid_test.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 array
+
+import (
+	"testing"
+
+	M "github.com/IBM/fp-go/v2/monoid/testing"
+)
+
+func TestMonoid(t *testing.T) {
+	M.AssertLaws(t, Monoid[int]())([][]int{{}, {1}, {1, 2}})
+}

v2/array/nonempty/array.go

@@ -0,0 +1,136 @@
+// Copyright (c) 2023 IBM Corp.
+// All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package nonempty
+
+import (
+	G "github.com/IBM/fp-go/v2/array/generic"
+	EM "github.com/IBM/fp-go/v2/endomorphism"
+	F "github.com/IBM/fp-go/v2/function"
+	"github.com/IBM/fp-go/v2/internal/array"
+	S "github.com/IBM/fp-go/v2/semigroup"
+)
+
+// NonEmptyArray represents an array with at least one element
+type NonEmptyArray[A any] []A
+
+// Of constructs a single element array
+func Of[A any](first A) NonEmptyArray[A] {
+	return G.Of[NonEmptyArray[A]](first)
+}
+
+// From constructs a [NonEmptyArray] from a set of variadic arguments
+func From[A any](first A, data ...A) NonEmptyArray[A] {
+	count := len(data)
+	if count == 0 {
+		return Of(first)
+	}
+	// allocate the requested buffer
+	buffer := make(NonEmptyArray[A], count+1)
+	buffer[0] = first
+	copy(buffer[1:], data)
+	return buffer
+}
+
+func IsEmpty[A any](_ NonEmptyArray[A]) bool {
+	return false
+}
+
+func IsNonEmpty[A any](_ NonEmptyArray[A]) bool {
+	return true
+}
+
+func MonadMap[A, B any](as NonEmptyArray[A], f func(a A) B) NonEmptyArray[B] {
+	return G.MonadMap[NonEmptyArray[A], NonEmptyArray[B]](as, f)
+}
+
+func Map[A, B any](f func(a A) B) func(NonEmptyArray[A]) NonEmptyArray[B] {
+	return F.Bind2nd(MonadMap[A, B], f)
+}
+
+func Reduce[A, B any](f func(B, A) B, initial B) func(NonEmptyArray[A]) B {
+	return func(as NonEmptyArray[A]) B {
+		return array.Reduce(as, f, initial)
+	}
+}
+
+func ReduceRight[A, B any](f func(A, B) B, initial B) func(NonEmptyArray[A]) B {
+	return func(as NonEmptyArray[A]) B {
+		return array.ReduceRight(as, f, initial)
+	}
+}
+
+func Tail[A any](as NonEmptyArray[A]) []A {
+	return as[1:]
+}
+
+func Head[A any](as NonEmptyArray[A]) A {
+	return as[0]
+}
+
+func First[A any](as NonEmptyArray[A]) A {
+	return as[0]
+}
+
+func Last[A any](as NonEmptyArray[A]) A {
+	return as[len(as)-1]
+}
+
+func Size[A any](as NonEmptyArray[A]) int {
+	return G.Size(as)
+}
+
+func Flatten[A any](mma NonEmptyArray[NonEmptyArray[A]]) NonEmptyArray[A] {
+	return G.Flatten(mma)
+}
+
+func MonadChain[A, B any](fa NonEmptyArray[A], f func(a A) NonEmptyArray[B]) NonEmptyArray[B] {
+	return G.MonadChain[NonEmptyArray[A], NonEmptyArray[B]](fa, f)
+}
+
+func Chain[A, B any](f func(A) NonEmptyArray[B]) func(NonEmptyArray[A]) NonEmptyArray[B] {
+	return G.Chain[NonEmptyArray[A], NonEmptyArray[B]](f)
+}
+
+func MonadAp[B, A any](fab NonEmptyArray[func(A) B], fa NonEmptyArray[A]) NonEmptyArray[B] {
+	return G.MonadAp[NonEmptyArray[B]](fab, fa)
+}
+
+func Ap[B, A any](fa NonEmptyArray[A]) func(NonEmptyArray[func(A) B]) NonEmptyArray[B] {
+	return G.Ap[NonEmptyArray[B], NonEmptyArray[func(A) B]](fa)
+}
+
+// FoldMap maps and folds a [NonEmptyArray]. Map the [NonEmptyArray] passing each value to the iterating function. Then fold the results using the provided [Semigroup].
+func FoldMap[A, B any](s S.Semigroup[B]) func(func(A) B) func(NonEmptyArray[A]) B {
+	return func(f func(A) B) func(NonEmptyArray[A]) B {
+		return func(as NonEmptyArray[A]) B {
+			return array.Reduce(Tail(as), func(cur B, a A) B {
+				return s.Concat(cur, f(a))
+			}, f(Head(as)))
+		}
+	}
+}
+
+// Fold folds the [NonEmptyArray] using the provided [Semigroup].
+func Fold[A any](s S.Semigroup[A]) func(NonEmptyArray[A]) A {
+	return func(as NonEmptyArray[A]) A {
+		return array.Reduce(Tail(as), s.Concat, Head(as))
+	}
+}
+
+// Prepend prepends a single value to an array
+func Prepend[A any](head A) EM.Endomorphism[NonEmptyArray[A]] {
+	return array.Prepend[EM.Endomorphism[NonEmptyArray[A]]](head)
+}

v2/array/sequence.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 array
+
+import (
+	F "github.com/IBM/fp-go/v2/function"
+	O "github.com/IBM/fp-go/v2/option"
+)
+
+// We need to pass the members of the applicative explicitly, because golang does neither support higher kinded types nor template methods on structs or interfaces
+
+// HKTA = HKT<A>
+// HKTRA = HKT<[]A>
+// HKTFRA = HKT<func(A)[]A>
+
+// Sequence takes an `Array` where elements are `HKT<A>` (higher kinded type) and,
+// using an applicative of that `HKT`, returns an `HKT` of `[]A`.
+// e.g. it can turn an `[]Either[error, string]` into an `Either[error, []string]`.
+//
+// Sequence requires an `Applicative` of the `HKT` you are targeting, e.g. to turn an
+// `[]Either[E, A]` into an `Either[E, []A]`, it needs an
+// Applicative` for `Either`, to to turn an `[]Option[A]` into an `Option[ []A]`,
+// it needs an `Applicative` for `Option`.
+func Sequence[A, HKTA, HKTRA, HKTFRA any](
+	_of func([]A) HKTRA,
+	_map func(HKTRA, func([]A) func(A) []A) HKTFRA,
+	_ap func(HKTFRA, HKTA) HKTRA,
+) func([]HKTA) HKTRA {
+	ca := F.Curry2(Append[A])
+	return Reduce(func(fas HKTRA, fa HKTA) HKTRA {
+		return _ap(
+			_map(fas, ca),
+			fa,
+		)
+	}, _of(Empty[A]()))
+}
+
+// ArrayOption returns a function to convert sequence of options into an option of a sequence
+func ArrayOption[A any]() func([]O.Option[A]) O.Option[[]A] {
+	return Sequence(
+		O.Of[[]A],
+		O.MonadMap[[]A, func(A) []A],
+		O.MonadAp[[]A, A],
+	)
+}

v2/array/sequence_test.go

@@ -0,0 +1,31 @@
+// 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 array
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	O "github.com/IBM/fp-go/v2/option"
+)
+
+func TestSequenceOption(t *testing.T) {
+	seq := ArrayOption[int]()
+
+	assert.Equal(t, O.Of([]int{1, 3}), seq([]O.Option[int]{O.Of(1), O.Of(3)}))
+	assert.Equal(t, O.None[[]int](), seq([]O.Option[int]{O.Of(1), O.None[int]()}))
+}

v2/array/sort.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 array
+
+import (
+	G "github.com/IBM/fp-go/v2/array/generic"
+	O "github.com/IBM/fp-go/v2/ord"
+)
+
+// Sort implements a stable sort on the array given the provided ordering
+func Sort[T any](ord O.Ord[T]) func(ma []T) []T {
+	return G.Sort[[]T](ord)
+}
+
+// SortByKey implements a stable sort on the array given the provided ordering on an extracted key
+func SortByKey[K, T any](ord O.Ord[K], f func(T) K) func(ma []T) []T {
+	return G.SortByKey[[]T](ord, f)
+}
+
+// SortBy implements a stable sort on the array given the provided ordering
+func SortBy[T any](ord []O.Ord[T]) func(ma []T) []T {
+	return G.SortBy[[]T, []O.Ord[T]](ord)
+}

v2/array/sort_test.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 array
+
+import (
+	"testing"
+
+	O "github.com/IBM/fp-go/v2/ord"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestSort(t *testing.T) {
+
+	ordInt := O.FromStrictCompare[int]()
+
+	input := []int{2, 1, 3}
+
+	res := Sort(ordInt)(input)
+
+	assert.Equal(t, []int{1, 2, 3}, res)
+	assert.Equal(t, []int{2, 1, 3}, input)
+
+}

v2/array/testing/laws.go

@@ -0,0 +1,74 @@
+// 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 testing
+
+import (
+	"testing"
+
+	RA "github.com/IBM/fp-go/v2/array"
+	EQ "github.com/IBM/fp-go/v2/eq"
+	L "github.com/IBM/fp-go/v2/internal/monad/testing"
+)
+
+// AssertLaws asserts the apply monad laws for the array monad
+func AssertLaws[A, B, C any](t *testing.T,
+	eqa EQ.Eq[A],
+	eqb EQ.Eq[B],
+	eqc EQ.Eq[C],
+
+	ab func(A) B,
+	bc func(B) C,
+) func(a A) bool {
+
+	return L.AssertLaws(t,
+		RA.Eq(eqa),
+		RA.Eq(eqb),
+		RA.Eq(eqc),
+
+		RA.Of[A],
+		RA.Of[B],
+		RA.Of[C],
+
+		RA.Of[func(A) A],
+		RA.Of[func(A) B],
+		RA.Of[func(B) C],
+		RA.Of[func(func(A) B) B],
+
+		RA.MonadMap[A, A],
+		RA.MonadMap[A, B],
+		RA.MonadMap[A, C],
+		RA.MonadMap[B, C],
+
+		RA.MonadMap[func(B) C, func(func(A) B) func(A) C],
+
+		RA.MonadChain[A, A],
+		RA.MonadChain[A, B],
+		RA.MonadChain[A, C],
+		RA.MonadChain[B, C],
+
+		RA.MonadAp[A, A],
+		RA.MonadAp[B, A],
+		RA.MonadAp[C, B],
+		RA.MonadAp[C, A],
+
+		RA.MonadAp[B, func(A) B],
+		RA.MonadAp[func(A) C, func(A) B],
+
+		ab,
+		bc,
+	)
+
+}

v2/array/testing/laws_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 testing
+
+import (
+	"fmt"
+	"testing"
+
+	EQ "github.com/IBM/fp-go/v2/eq"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestMonadLaws(t *testing.T) {
+	// some comparison
+	eqa := EQ.FromStrictEquals[bool]()
+	eqb := EQ.FromStrictEquals[int]()
+	eqc := EQ.FromStrictEquals[string]()
+
+	ab := func(a bool) int {
+		if a {
+			return 1
+		}
+		return 0
+	}
+
+	bc := func(b int) string {
+		return fmt.Sprintf("value %d", b)
+	}
+
+	laws := AssertLaws(t, eqa, eqb, eqc, ab, bc)
+
+	assert.True(t, laws(true))
+	assert.True(t, laws(false))
+}

v2/array/traverse.go

@@ -0,0 +1,40 @@
+// Copyright (c) 2023 IBM Corp.
+// All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package array
+
+import (
+	"github.com/IBM/fp-go/v2/internal/array"
+)
+
+func Traverse[A, B, HKTB, HKTAB, HKTRB any](
+	fof func([]B) HKTRB,
+	fmap func(func([]B) func(B) []B) func(HKTRB) HKTAB,
+	fap func(HKTB) func(HKTAB) HKTRB,
+
+	f func(A) HKTB) func([]A) HKTRB {
+	return array.Traverse[[]A](fof, fmap, fap, f)
+}
+
+func MonadTraverse[A, B, HKTB, HKTAB, HKTRB any](
+	fof func([]B) HKTRB,
+	fmap func(func([]B) func(B) []B) func(HKTRB) HKTAB,
+	fap func(HKTB) func(HKTAB) HKTRB,
+
+	ta []A,
+	f func(A) HKTB) HKTRB {
+
+	return array.MonadTraverse(fof, fmap, fap, ta, f)
+}

v2/array/traverse_test.go

@@ -0,0 +1,43 @@
+// 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 array
+
+import (
+	"testing"
+
+	O "github.com/IBM/fp-go/v2/option"
+	"github.com/stretchr/testify/assert"
+)
+
+type ArrayType = []int
+
+func TestTraverse(t *testing.T) {
+
+	traverse := Traverse(
+		O.Of[ArrayType],
+		O.Map[ArrayType, func(int) ArrayType],
+		O.Ap[ArrayType, int],
+
+		func(n int) O.Option[int] {
+			if n%2 == 0 {
+				return O.None[int]()
+			}
+			return O.Of(n)
+		})
+
+	assert.Equal(t, O.None[[]int](), traverse(ArrayType{1, 2}))
+	assert.Equal(t, O.Of(ArrayType{1, 3}), traverse(ArrayType{1, 3}))
+}

v2/array/uniq.go

@@ -0,0 +1,17 @@
+package array
+
+import (
+	G "github.com/IBM/fp-go/v2/array/generic"
+)
+
+// StrictUniq converts an array of arbitrary items into an array or unique items
+// where uniqueness is determined by the built-in uniqueness constraint
+func StrictUniq[A comparable](as []A) []A {
+	return G.StrictUniq[[]A](as)
+}
+
+// Uniq converts an array of arbitrary items into an array or unique items
+// where uniqueness is determined based on a key extractor function
+func Uniq[A any, K comparable](f func(A) K) func(as []A) []A {
+	return G.Uniq[[]A](f)
+}

v2/array/uniq_test.go

@@ -0,0 +1,14 @@
+package array
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestUniq(t *testing.T) {
+	data := From(1, 2, 3, 2, 4, 1)
+
+	uniq := StrictUniq(data)
+	assert.Equal(t, From(1, 2, 3, 4), uniq)
+}

v2/array/zip.go

@@ -0,0 +1,38 @@
+// 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 array
+
+import (
+	G "github.com/IBM/fp-go/v2/array/generic"
+	T "github.com/IBM/fp-go/v2/tuple"
+)
+
+// ZipWith applies a function to pairs of elements at the same index in two arrays, collecting the results in a new array. If one
+// input array is short, excess elements of the longer array are discarded.
+func ZipWith[FCT ~func(A, B) C, A, B, C any](fa []A, fb []B, f FCT) []C {
+	return G.ZipWith[[]A, []B, []C, FCT](fa, fb, f)
+}
+
+// Zip takes two arrays and returns an array of corresponding pairs. If one input array is short, excess elements of the
+// longer array are discarded
+func Zip[A, B any](fb []B) func([]A) []T.Tuple2[A, B] {
+	return G.Zip[[]A, []B, []T.Tuple2[A, B]](fb)
+}
+
+// Unzip is the function is reverse of [Zip]. Takes an array of pairs and return two corresponding arrays
+func Unzip[A, B any](cs []T.Tuple2[A, B]) T.Tuple2[[]A, []B] {
+	return G.Unzip[[]A, []B, []T.Tuple2[A, B]](cs)
+}

v2/array/zip_test.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 array
+
+import (
+	"fmt"
+	"testing"
+
+	T "github.com/IBM/fp-go/v2/tuple"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestZipWith(t *testing.T) {
+	left := From(1, 2, 3)
+	right := From("a", "b", "c", "d")
+
+	res := ZipWith(left, right, func(l int, r string) string {
+		return fmt.Sprintf("%s%d", r, l)
+	})
+
+	assert.Equal(t, From("a1", "b2", "c3"), res)
+}
+
+func TestZip(t *testing.T) {
+	left := From(1, 2, 3)
+	right := From("a", "b", "c", "d")
+
+	res := Zip[string](left)(right)
+
+	assert.Equal(t, From(T.MakeTuple2("a", 1), T.MakeTuple2("b", 2), T.MakeTuple2("c", 3)), res)
+}
+
+func TestUnzip(t *testing.T) {
+	left := From(1, 2, 3)
+	right := From("a", "b", "c")
+
+	zipped := Zip[string](left)(right)
+
+	unzipped := Unzip(zipped)
+
+	assert.Equal(t, right, unzipped.F1)
+	assert.Equal(t, left, unzipped.F2)
+}

v2/assert/assert_test.go

@@ -0,0 +1,109 @@
+// 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 assert
+
+import (
+	"fmt"
+	"testing"
+
+	E "github.com/IBM/fp-go/v2/either"
+	EQ "github.com/IBM/fp-go/v2/eq"
+	"github.com/stretchr/testify/assert"
+)
+
+var (
+	errTest = fmt.Errorf("test failure")
+
+	// Eq is the equal predicate checking if objects are equal
+	Eq = EQ.FromEquals(assert.ObjectsAreEqual)
+)
+
+func wrap1[T any](wrapped func(t assert.TestingT, expected, actual any, msgAndArgs ...any) bool, t *testing.T, expected T) func(actual T) E.Either[error, T] {
+	return func(actual T) E.Either[error, T] {
+		ok := wrapped(t, expected, actual)
+		if ok {
+			return E.Of[error](actual)
+		}
+		return E.Left[T](errTest)
+	}
+}
+
+// NotEqual tests if the expected and the actual values are not equal
+func NotEqual[T any](t *testing.T, expected T) func(actual T) E.Either[error, T] {
+	return wrap1(assert.NotEqual, t, expected)
+}
+
+// Equal tests if the expected and the actual values are equal
+func Equal[T any](t *testing.T, expected T) func(actual T) E.Either[error, T] {
+	return wrap1(assert.Equal, t, expected)
+}
+
+// Length tests if an array has the expected length
+func Length[T any](t *testing.T, expected int) func(actual []T) E.Either[error, []T] {
+	return func(actual []T) E.Either[error, []T] {
+		ok := assert.Len(t, actual, expected)
+		if ok {
+			return E.Of[error](actual)
+		}
+		return E.Left[[]T](errTest)
+	}
+}
+
+// NoError validates that there is no error
+func NoError[T any](t *testing.T) func(actual E.Either[error, T]) E.Either[error, T] {
+	return func(actual E.Either[error, T]) E.Either[error, T] {
+		return E.MonadFold(actual, func(e error) E.Either[error, T] {
+			assert.NoError(t, e)
+			return E.Left[T](e)
+		}, func(value T) E.Either[error, T] {
+			assert.NoError(t, nil)
+			return E.Right[error](value)
+		})
+	}
+}
+
+// ArrayContains tests if a value is contained in an array
+func ArrayContains[T any](t *testing.T, expected T) func(actual []T) E.Either[error, []T] {
+	return func(actual []T) E.Either[error, []T] {
+		ok := assert.Contains(t, actual, expected)
+		if ok {
+			return E.Of[error](actual)
+		}
+		return E.Left[[]T](errTest)
+	}
+}
+
+// ContainsKey tests if a key is contained in a map
+func ContainsKey[T any, K comparable](t *testing.T, expected K) func(actual map[K]T) E.Either[error, map[K]T] {
+	return func(actual map[K]T) E.Either[error, map[K]T] {
+		ok := assert.Contains(t, actual, expected)
+		if ok {
+			return E.Of[error](actual)
+		}
+		return E.Left[map[K]T](errTest)
+	}
+}
+
+// NotContainsKey tests if a key is not contained in a map
+func NotContainsKey[T any, K comparable](t *testing.T, expected K) func(actual map[K]T) E.Either[error, map[K]T] {
+	return func(actual map[K]T) E.Either[error, map[K]T] {
+		ok := assert.NotContains(t, actual, expected)
+		if ok {
+			return E.Of[error](actual)
+		}
+		return E.Left[map[K]T](errTest)
+	}
+}

v2/boolean/boolean.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 boolean
+
+import (
+	"github.com/IBM/fp-go/v2/eq"
+	"github.com/IBM/fp-go/v2/monoid"
+	"github.com/IBM/fp-go/v2/ord"
+)
+
+var (
+	// MonoidAny is the boolean [monoid.Monoid] under disjunction
+	MonoidAny = monoid.MakeMonoid(
+		func(l, r bool) bool {
+			return l || r
+		},
+		false,
+	)
+
+	// MonoidAll is the boolean [monoid.Monoid] under conjuction
+	MonoidAll = monoid.MakeMonoid(
+		func(l, r bool) bool {
+			return l && r
+		},
+		true,
+	)
+
+	// Eq is the equals predicate for boolean
+	Eq = eq.FromStrictEquals[bool]()
+
+	// Ord is the strict ordering for boolean
+	Ord = ord.MakeOrd(func(l, r bool) int {
+		if l {
+			if r {
+				return 0
+			}
+			return +1
+		}
+		if r {
+			return -1
+		}
+		return 0
+	}, func(l, r bool) bool {
+		return l == r
+	})
+)

v2/boolean/types.go

@@ -0,0 +1,22 @@
+// 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 boolean
+
+import "github.com/IBM/fp-go/v2/monoid"
+
+type (
+	Monoid = monoid.Monoid[bool]
+)

v2/bounded/bounded.go

@@ -0,0 +1,62 @@
+// 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 bounded
+
+import "github.com/IBM/fp-go/v2/ord"
+
+type Bounded[T any] interface {
+	ord.Ord[T]
+	Top() T
+	Bottom() T
+}
+
+type bounded[T any] struct {
+	c func(x, y T) int
+	e func(x, y T) bool
+	t T
+	b T
+}
+
+func (b bounded[T]) Equals(x, y T) bool {
+	return b.e(x, y)
+}
+
+func (b bounded[T]) Compare(x, y T) int {
+	return b.c(x, y)
+}
+
+func (b bounded[T]) Top() T {
+	return b.t
+}
+
+func (b bounded[T]) Bottom() T {
+	return b.b
+}
+
+// MakeBounded creates an instance of a bounded type
+func MakeBounded[T any](o ord.Ord[T], t, b T) Bounded[T] {
+	return bounded[T]{c: o.Compare, e: o.Equals, t: t, b: b}
+}
+
+// Clamp returns a function that clamps against the bounds defined in the bounded type
+func Clamp[T any](b Bounded[T]) func(T) T {
+	return ord.Clamp[T](b)(b.Bottom(), b.Top())
+}
+
+// Reverse reverses the ordering and swaps the bounds
+func Reverse[T any](b Bounded[T]) Bounded[T] {
+	return MakeBounded(ord.Reverse(b), b.Bottom(), b.Top())
+}

v2/bytes/bytes.go

@@ -0,0 +1,28 @@
+// 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 bytes
+
+func Empty() []byte {
+	return Monoid.Empty()
+}
+
+func ToString(a []byte) string {
+	return string(a)
+}
+
+func Size(as []byte) int {
+	return len(as)
+}

v2/bytes/monoid.go

@@ -0,0 +1,34 @@
+// 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 bytes
+
+import (
+	"bytes"
+
+	A "github.com/IBM/fp-go/v2/array"
+	O "github.com/IBM/fp-go/v2/ord"
+)
+
+var (
+	// monoid for byte arrays
+	Monoid = A.Monoid[byte]()
+
+	// ConcatAll concatenates all bytes
+	ConcatAll = A.ArrayConcatAll[byte]
+
+	// Ord implements the default ordering on bytes
+	Ord = O.MakeOrd(bytes.Compare, bytes.Equal)
+)

v2/bytes/monoid_test.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 bytes
+
+import (
+	"testing"
+
+	M "github.com/IBM/fp-go/v2/monoid/testing"
+)
+
+func TestMonoid(t *testing.T) {
+	M.AssertLaws(t, Monoid)([][]byte{[]byte(""), []byte("a"), []byte("some value")})
+}

v2/cli/apply.go

@@ -0,0 +1,432 @@
+// 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 cli
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"time"
+
+	C "github.com/urfave/cli/v2"
+)
+
+func generateTraverseTuple(f *os.File, i int) {
+	fmt.Fprintf(f, "\n// TraverseTuple%d is a utility function used to implement the sequence operation for higher kinded types based only on map and ap.\n", i)
+	fmt.Fprintf(f, "// The function takes a [Tuple%d] of base types and %d functions that transform these based types into higher higher kinded types. It returns a higher kinded type of a [Tuple%d] with the resolved values.\n", i, i, i)
+	fmt.Fprintf(f, "func TraverseTuple%d[\n", i)
+	// map as the starting point
+	fmt.Fprintf(f, "  MAP ~func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, " ")
+		}
+		fmt.Fprintf(f, "func(T%d)", j+1)
+	}
+	fmt.Fprintf(f, " ")
+	fmt.Fprintf(f, "T.")
+	writeTupleType(f, "T", i)
+	fmt.Fprintf(f, ") func(HKT_T1)")
+	if i > 1 {
+		fmt.Fprintf(f, " HKT_F")
+		for k := 1; k < i; k++ {
+			fmt.Fprintf(f, "_T%d", k+1)
+		}
+	} else {
+		fmt.Fprintf(f, " HKT_TUPLE%d", i)
+	}
+	fmt.Fprintf(f, ",\n")
+	// the applicatives
+	for j := 1; j < i; j++ {
+		fmt.Fprintf(f, "  AP%d ~func(", j)
+		fmt.Fprintf(f, "HKT_T%d) func(", j+1)
+		fmt.Fprintf(f, "HKT_F")
+		for k := j; k < i; k++ {
+			fmt.Fprintf(f, "_T%d", k+1)
+		}
+		fmt.Fprintf(f, ")")
+		if j+1 < i {
+			fmt.Fprintf(f, " HKT_F")
+			for k := j + 1; k < i; k++ {
+				fmt.Fprintf(f, "_T%d", k+1)
+			}
+		} else {
+			fmt.Fprintf(f, " HKT_TUPLE%d", i)
+		}
+		fmt.Fprintf(f, ",\n")
+	}
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, "  F%d ~func(A%d) HKT_T%d,\n", j+1, j+1, j+1)
+	}
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, "  A%d, T%d,\n", j+1, j+1)
+	}
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, "  HKT_T%d, // HKT[T%d]\n", j+1, j+1)
+	}
+	for j := 1; j < i; j++ {
+		fmt.Fprintf(f, "  HKT_F")
+		for k := j; k < i; k++ {
+			fmt.Fprintf(f, "_T%d", k+1)
+		}
+		fmt.Fprintf(f, ", // HKT[")
+		for k := j; k < i; k++ {
+			fmt.Fprintf(f, "func(T%d) ", k+1)
+		}
+		fmt.Fprintf(f, "T.")
+		writeTupleType(f, "T", i)
+		fmt.Fprintf(f, "]\n")
+	}
+	fmt.Fprintf(f, "  HKT_TUPLE%d any, // HKT[", i)
+	writeTupleType(f, "T", i)
+	fmt.Fprintf(f, "]\n")
+	fmt.Fprintf(f, "](\n")
+
+	// the callbacks
+	fmt.Fprintf(f, "  fmap MAP,\n")
+	for j := 1; j < i; j++ {
+		fmt.Fprintf(f, "  fap%d AP%d,\n", j, j)
+	}
+	// the transformer functions
+	for j := 1; j <= i; j++ {
+		fmt.Fprintf(f, "  f%d F%d,\n", j, j)
+	}
+	// the parameters
+	fmt.Fprintf(f, "  t T.Tuple%d[", i)
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "A%d", j+1)
+	}
+	fmt.Fprintf(f, "],\n")
+	fmt.Fprintf(f, ") HKT_TUPLE%d {\n", i)
+
+	fmt.Fprintf(f, "  return F.Pipe%d(\n", i)
+	fmt.Fprintf(f, "    f1(t.F1),\n")
+	fmt.Fprintf(f, "    fmap(tupleConstructor%d[", i)
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j+1)
+	}
+	fmt.Fprintf(f, "]()),\n")
+	for j := 1; j < i; j++ {
+		fmt.Fprintf(f, "    fap%d(f%d(t.F%d)),\n", j, j+1, j+1)
+	}
+	fmt.Fprintf(f, ")\n")
+	fmt.Fprintf(f, "}\n")
+}
+
+func generateSequenceTuple(f *os.File, i int) {
+	fmt.Fprintf(f, "\n// SequenceTuple%d is a utility function used to implement the sequence operation for higher kinded types based only on map and ap.\n", i)
+	fmt.Fprintf(f, "// The function takes a [Tuple%d] of higher higher kinded types and returns a higher kinded type of a [Tuple%d] with the resolved values.\n", i, i)
+	fmt.Fprintf(f, "func SequenceTuple%d[\n", i)
+	// map as the starting point
+	fmt.Fprintf(f, "  MAP ~func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, " ")
+		}
+		fmt.Fprintf(f, "func(T%d)", j+1)
+	}
+	fmt.Fprintf(f, " ")
+	fmt.Fprintf(f, "T.")
+	writeTupleType(f, "T", i)
+	fmt.Fprintf(f, ") func(HKT_T1)")
+	if i > 1 {
+		fmt.Fprintf(f, " HKT_F")
+		for k := 1; k < i; k++ {
+			fmt.Fprintf(f, "_T%d", k+1)
+		}
+	} else {
+		fmt.Fprintf(f, " HKT_TUPLE%d", i)
+	}
+	fmt.Fprintf(f, ",\n")
+	// the applicatives
+	for j := 1; j < i; j++ {
+		fmt.Fprintf(f, "  AP%d ~func(", j)
+		fmt.Fprintf(f, "HKT_T%d) func(", j+1)
+		fmt.Fprintf(f, "HKT_F")
+		for k := j; k < i; k++ {
+			fmt.Fprintf(f, "_T%d", k+1)
+		}
+		fmt.Fprintf(f, ")")
+		if j+1 < i {
+			fmt.Fprintf(f, " HKT_F")
+			for k := j + 1; k < i; k++ {
+				fmt.Fprintf(f, "_T%d", k+1)
+			}
+		} else {
+			fmt.Fprintf(f, " HKT_TUPLE%d", i)
+		}
+		fmt.Fprintf(f, ",\n")
+	}
+
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, "  T%d,\n", j+1)
+	}
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, "  HKT_T%d, // HKT[T%d]\n", j+1, j+1)
+	}
+	for j := 1; j < i; j++ {
+		fmt.Fprintf(f, "  HKT_F")
+		for k := j; k < i; k++ {
+			fmt.Fprintf(f, "_T%d", k+1)
+		}
+		fmt.Fprintf(f, ", // HKT[")
+		for k := j; k < i; k++ {
+			fmt.Fprintf(f, "func(T%d) ", k+1)
+		}
+		fmt.Fprintf(f, "T.")
+		writeTupleType(f, "T", i)
+		fmt.Fprintf(f, "]\n")
+	}
+	fmt.Fprintf(f, "  HKT_TUPLE%d any, // HKT[", i)
+	writeTupleType(f, "T", i)
+	fmt.Fprintf(f, "]\n")
+	fmt.Fprintf(f, "](\n")
+
+	// the callbacks
+	fmt.Fprintf(f, "  fmap MAP,\n")
+	for j := 1; j < i; j++ {
+		fmt.Fprintf(f, "  fap%d AP%d,\n", j, j)
+	}
+	// the parameters
+	fmt.Fprintf(f, "  t T.Tuple%d[", i)
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "HKT_T%d", j+1)
+	}
+	fmt.Fprintf(f, "],\n")
+	fmt.Fprintf(f, ") HKT_TUPLE%d {\n", i)
+
+	fmt.Fprintf(f, "  return F.Pipe%d(\n", i)
+	fmt.Fprintf(f, "    t.F1,\n")
+	fmt.Fprintf(f, "    fmap(tupleConstructor%d[", i)
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j+1)
+	}
+	fmt.Fprintf(f, "]()),\n")
+	for j := 1; j < i; j++ {
+		fmt.Fprintf(f, "    fap%d(t.F%d),\n", j, j+1)
+	}
+	fmt.Fprintf(f, ")\n")
+	fmt.Fprintf(f, "}\n")
+}
+
+func generateSequenceT(f *os.File, i int) {
+	fmt.Fprintf(f, "\n// SequenceT%d is a utility function used to implement the sequence operation for higher kinded types based only on map and ap.\n", i)
+	fmt.Fprintf(f, "// The function takes %d higher higher kinded types and returns a higher kinded type of a [Tuple%d] with the resolved values.\n", i, i)
+	fmt.Fprintf(f, "func SequenceT%d[\n", i)
+	// map as the starting point
+	fmt.Fprintf(f, "  MAP ~func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, " ")
+		}
+		fmt.Fprintf(f, "func(T%d)", j+1)
+	}
+	fmt.Fprintf(f, " ")
+	fmt.Fprintf(f, "T.")
+	writeTupleType(f, "T", i)
+	fmt.Fprintf(f, ") func(HKT_T1)")
+	if i > 1 {
+		fmt.Fprintf(f, " HKT_F")
+		for k := 1; k < i; k++ {
+			fmt.Fprintf(f, "_T%d", k+1)
+		}
+	} else {
+		fmt.Fprintf(f, " HKT_TUPLE%d", i)
+	}
+	fmt.Fprintf(f, ",\n")
+	// the applicatives
+	for j := 1; j < i; j++ {
+		fmt.Fprintf(f, "  AP%d ~func(", j)
+		fmt.Fprintf(f, "HKT_T%d) func(", j+1)
+		fmt.Fprintf(f, "HKT_F")
+		for k := j; k < i; k++ {
+			fmt.Fprintf(f, "_T%d", k+1)
+		}
+		fmt.Fprintf(f, ")")
+		if j+1 < i {
+			fmt.Fprintf(f, " HKT_F")
+			for k := j + 1; k < i; k++ {
+				fmt.Fprintf(f, "_T%d", k+1)
+			}
+		} else {
+			fmt.Fprintf(f, " HKT_TUPLE%d", i)
+		}
+		fmt.Fprintf(f, ",\n")
+	}
+
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, "  T%d,\n", j+1)
+	}
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, "  HKT_T%d, // HKT[T%d]\n", j+1, j+1)
+	}
+	for j := 1; j < i; j++ {
+		fmt.Fprintf(f, "  HKT_F")
+		for k := j; k < i; k++ {
+			fmt.Fprintf(f, "_T%d", k+1)
+		}
+		fmt.Fprintf(f, ", // HKT[")
+		for k := j; k < i; k++ {
+			fmt.Fprintf(f, "func(T%d) ", k+1)
+		}
+		fmt.Fprintf(f, "T.")
+		writeTupleType(f, "T", i)
+		fmt.Fprintf(f, "]\n")
+	}
+	fmt.Fprintf(f, "  HKT_TUPLE%d any, // HKT[", i)
+	writeTupleType(f, "T", i)
+	fmt.Fprintf(f, "]\n")
+	fmt.Fprintf(f, "](\n")
+
+	// the callbacks
+	fmt.Fprintf(f, "  fmap MAP,\n")
+	for j := 1; j < i; j++ {
+		fmt.Fprintf(f, "  fap%d AP%d,\n", j, j)
+	}
+	// the parameters
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, "  t%d HKT_T%d,\n", j+1, j+1)
+	}
+	fmt.Fprintf(f, ") HKT_TUPLE%d {\n", i)
+
+	fmt.Fprintf(f, "  return F.Pipe%d(\n", i)
+	fmt.Fprintf(f, "    t1,\n")
+	fmt.Fprintf(f, "    fmap(tupleConstructor%d[", i)
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j+1)
+	}
+	fmt.Fprintf(f, "]()),\n")
+	for j := 1; j < i; j++ {
+		fmt.Fprintf(f, "    fap%d(t%d),\n", j, j+1)
+	}
+	fmt.Fprintf(f, ")\n")
+	fmt.Fprintf(f, "}\n")
+}
+
+func generateTupleConstructor(f *os.File, i int) {
+	// Create the optionize version
+	fmt.Fprintf(f, "\n// tupleConstructor%d returns a curried version of [T.MakeTuple%d]\n", i, i)
+	fmt.Fprintf(f, "func tupleConstructor%d[", i)
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j+1)
+	}
+	fmt.Fprintf(f, " any]()")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, " func(T%d)", j+1)
+	}
+	fmt.Fprintf(f, " T.Tuple%d[", i)
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j+1)
+	}
+	fmt.Fprintf(f, "] {\n")
+
+	fmt.Fprintf(f, "  return F.Curry%d(T.MakeTuple%d[", i, i)
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j+1)
+	}
+	fmt.Fprintf(f, "])\n")
+
+	fmt.Fprintf(f, "}\n")
+}
+
+func generateApplyHelpers(filename string, count int) error {
+	dir, err := os.Getwd()
+	if err != nil {
+		return err
+	}
+	absDir, err := filepath.Abs(dir)
+	if err != nil {
+		return err
+	}
+	pkg := filepath.Base(absDir)
+	f, err := os.Create(filepath.Clean(filename))
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	// log
+	log.Printf("Generating code in [%s] for package [%s] with [%d] repetitions ...", filename, pkg, count)
+
+	// some header
+	fmt.Fprintln(f, "// Code generated by go generate; DO NOT EDIT.")
+	fmt.Fprintln(f, "// This file was generated by robots at")
+	fmt.Fprintf(f, "// %s\n\n", time.Now())
+
+	fmt.Fprintf(f, "package %s\n\n", pkg)
+
+	// print out some helpers
+	fmt.Fprintf(f, `
+import (
+	F "github.com/IBM/fp-go/v2/function"
+	T "github.com/IBM/fp-go/v2/tuple"
+)
+`)
+
+	for i := 1; i <= count; i++ {
+		// tuple constructor
+		generateTupleConstructor(f, i)
+		// sequenceT
+		generateSequenceT(f, i)
+		// sequenceTuple
+		generateSequenceTuple(f, i)
+		// traverseTuple
+		generateTraverseTuple(f, i)
+	}
+
+	return nil
+}
+
+func ApplyCommand() *C.Command {
+	return &C.Command{
+		Name:  "apply",
+		Usage: "generate code for the sequence operations of apply",
+		Flags: []C.Flag{
+			flagCount,
+			flagFilename,
+		},
+		Action: func(ctx *C.Context) error {
+			return generateApplyHelpers(
+				ctx.String(keyFilename),
+				ctx.Int(keyCount),
+			)
+		},
+	}
+}

v2/cli/bind.go

@@ -0,0 +1,294 @@
+// 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 cli
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"time"
+
+	C "github.com/urfave/cli/v2"
+)
+
+func createCombinations(n int, all, prev []int) [][]int {
+	l := len(prev)
+	if l == n {
+		return [][]int{prev}
+	}
+	var res [][]int
+	for idx, val := range all {
+		cpy := make([]int, l+1)
+		copy(cpy, prev)
+		cpy[l] = val
+
+		res = append(res, createCombinations(n, all[idx+1:], cpy)...)
+	}
+	return res
+}
+
+func remaining(comb []int, total int) []int {
+	var res []int
+	mp := make(map[int]int)
+	for _, idx := range comb {
+		mp[idx] = idx
+	}
+	for i := 1; i <= total; i++ {
+		_, ok := mp[i]
+		if !ok {
+			res = append(res, i)
+		}
+	}
+	return res
+}
+
+func generateCombSingleBind(f *os.File, comb [][]int, total int) {
+	for _, c := range comb {
+		// remaining indexes
+		rem := remaining(c, total)
+
+		// bind function
+		fmt.Fprintf(f, "\n// Bind")
+		for _, idx := range c {
+			fmt.Fprintf(f, "%d", idx)
+		}
+		fmt.Fprintf(f, "of%d takes a function with %d parameters and returns a new function with %d parameters that will bind these parameters to the positions [", total, total, len(c))
+		for i, idx := range c {
+			if i > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "%d", idx)
+		}
+		fmt.Fprintf(f, "] of the original function.\n// The return value of is a function with the remaining %d parameters at positions [", len(rem))
+		for i, idx := range rem {
+			if i > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "%d", idx)
+		}
+		fmt.Fprintf(f, "] of the original function.\n")
+		fmt.Fprintf(f, "func Bind")
+		for _, idx := range c {
+			fmt.Fprintf(f, "%d", idx)
+		}
+		fmt.Fprintf(f, "of%d[F ~func(", total)
+		for i := 0; i < total; i++ {
+			if i > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "T%d", i+1)
+		}
+		fmt.Fprintf(f, ") R")
+		for i := 0; i < total; i++ {
+			fmt.Fprintf(f, ", T%d", i+1)
+		}
+		fmt.Fprintf(f, ", R any](f F) func(")
+		for i, idx := range c {
+			if i > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "T%d", idx)
+		}
+		fmt.Fprintf(f, ") func(")
+		for i, idx := range rem {
+			if i > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "T%d", idx)
+		}
+		fmt.Fprintf(f, ") R {\n")
+
+		fmt.Fprintf(f, "  return func(")
+
+		for i, idx := range c {
+			if i > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "t%d T%d", idx, idx)
+		}
+		fmt.Fprintf(f, ") func(")
+		for i, idx := range rem {
+			if i > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "T%d", idx)
+		}
+		fmt.Fprintf(f, ") R {\n")
+
+		fmt.Fprintf(f, "    return func(")
+		for i, idx := range rem {
+			if i > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "t%d T%d", idx, idx)
+		}
+		fmt.Fprintf(f, ") R {\n")
+
+		fmt.Fprintf(f, "      return f(")
+		for i := 1; i <= total; i++ {
+			if i > 1 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "t%d", i)
+		}
+		fmt.Fprintf(f, ")\n")
+
+		fmt.Fprintf(f, "    }\n")
+		fmt.Fprintf(f, "  }\n")
+		fmt.Fprintf(f, "}\n")
+
+		// ignore function
+		fmt.Fprintf(f, "\n// Ignore")
+		for _, idx := range c {
+			fmt.Fprintf(f, "%d", idx)
+		}
+		fmt.Fprintf(f, "of%d takes a function with %d parameters and returns a new function with %d parameters that will ignore the values at positions [", total, len(rem), total)
+		for i, idx := range c {
+			if i > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "%d", idx)
+		}
+		fmt.Fprintf(f, "] and pass the remaining %d parameters to the original function\n", len(rem))
+		fmt.Fprintf(f, "func Ignore")
+		for _, idx := range c {
+			fmt.Fprintf(f, "%d", idx)
+		}
+		fmt.Fprintf(f, "of%d[", total)
+		// start with the undefined parameters
+		for i, idx := range c {
+			if i > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "T%d", idx)
+		}
+		if len(c) > 0 {
+			fmt.Fprintf(f, " any, ")
+		}
+		fmt.Fprintf(f, "F ~func(")
+		for i, idx := range rem {
+			if i > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "T%d", idx)
+		}
+		fmt.Fprintf(f, ") R")
+		for _, idx := range rem {
+			fmt.Fprintf(f, ", T%d", idx)
+		}
+		fmt.Fprintf(f, ", R any](f F) func(")
+		for i := 0; i < total; i++ {
+			if i > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "T%d", i+1)
+		}
+		fmt.Fprintf(f, ") R {\n")
+
+		fmt.Fprintf(f, "  return func(")
+		for i := 0; i < total; i++ {
+			if i > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "t%d T%d", i+1, i+1)
+		}
+		fmt.Fprintf(f, ") R {\n")
+		fmt.Fprintf(f, "      return f(")
+		for i, idx := range rem {
+			if i > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "t%d", idx)
+		}
+		fmt.Fprintf(f, ")\n")
+
+		fmt.Fprintf(f, "  }\n")
+		fmt.Fprintf(f, "}\n")
+
+	}
+}
+
+func generateSingleBind(f *os.File, total int) {
+
+	fmt.Fprintf(f, "// Combinations for a total of %d arguments\n", total)
+
+	// construct the indexes
+	all := make([]int, total)
+	for i := 0; i < total; i++ {
+		all[i] = i + 1
+	}
+	// for all permutations of a certain length
+	for j := 0; j < total; j++ {
+		// get combinations of that size
+		comb := createCombinations(j+1, all, []int{})
+		generateCombSingleBind(f, comb, total)
+	}
+}
+
+func generateBind(f *os.File, i int) {
+	for j := 1; j < i; j++ {
+		generateSingleBind(f, j)
+	}
+}
+
+func generateBindHelpers(filename string, count int) error {
+	dir, err := os.Getwd()
+	if err != nil {
+		return err
+	}
+	absDir, err := filepath.Abs(dir)
+	if err != nil {
+		return err
+	}
+	pkg := filepath.Base(absDir)
+	f, err := os.Create(filepath.Clean(filename))
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	// log
+	log.Printf("Generating code in [%s] for package [%s] with [%d] repetitions ...", filename, pkg, count)
+
+	// some header
+	fmt.Fprintln(f, "// Code generated by go generate; DO NOT EDIT.")
+	fmt.Fprintln(f, "// This file was generated by robots at")
+	fmt.Fprintf(f, "// %s\n\n", time.Now())
+
+	fmt.Fprintf(f, "package %s\n", pkg)
+
+	generateBind(f, count)
+
+	return nil
+}
+
+func BindCommand() *C.Command {
+	return &C.Command{
+		Name:        "bind",
+		Usage:       "generate code for binder functions etc",
+		Description: "Code generation for bind, etc",
+		Flags: []C.Flag{
+			flagCount,
+			flagFilename,
+		},
+		Action: func(ctx *C.Context) error {
+			return generateBindHelpers(
+				ctx.String(keyFilename),
+				ctx.Int(keyCount),
+			)
+		},
+	}
+}

v2/cli/commands.go

@@ -0,0 +1,39 @@
+// 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 cli
+
+import (
+	C "github.com/urfave/cli/v2"
+)
+
+func Commands() []*C.Command {
+	return []*C.Command{
+		PipeCommand(),
+		IdentityCommand(),
+		OptionCommand(),
+		EitherCommand(),
+		TupleCommand(),
+		BindCommand(),
+		ApplyCommand(),
+		ContextReaderIOEitherCommand(),
+		ReaderIOEitherCommand(),
+		ReaderCommand(),
+		IOEitherCommand(),
+		IOCommand(),
+		IOOptionCommand(),
+		DICommand(),
+	}
+}

v2/cli/common.go

@@ -0,0 +1,39 @@
+// 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 cli
+
+import (
+	C "github.com/urfave/cli/v2"
+)
+
+const (
+	keyFilename = "filename"
+	keyCount    = "count"
+)
+
+var (
+	flagFilename = &C.StringFlag{
+		Name:  keyFilename,
+		Value: "gen.go",
+		Usage: "Name of the generated file",
+	}
+
+	flagCount = &C.IntFlag{
+		Name:  keyCount,
+		Value: 20,
+		Usage: "Number of variations to create",
+	}
+)

v2/cli/contextreaderioeither.go

@@ -0,0 +1,271 @@
+// 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 cli
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"strings"
+
+	A "github.com/IBM/fp-go/v2/array"
+	C "github.com/urfave/cli/v2"
+)
+
+// Deprecated:
+func generateNestedCallbacks(i, total int) string {
+	var buf strings.Builder
+	for j := i; j < total; j++ {
+		if j > i {
+			buf.WriteString(" ")
+		}
+		buf.WriteString(fmt.Sprintf("func(T%d)", j+1))
+	}
+	if i > 0 {
+		buf.WriteString(" ")
+	}
+	buf.WriteString(tupleType("T")(total))
+	return buf.String()
+}
+
+func generateNestedCallbacksPlain(i, total int) string {
+	fs := A.MakeBy(total-i, func(j int) string {
+		return fmt.Sprintf("func(T%d)", j+i+1)
+	})
+	ts := A.Of(tupleTypePlain("T")(total))
+	return joinAll(" ")(fs, ts)
+}
+
+func generateContextReaderIOEitherEitherize(f, fg *os.File, i int) {
+	// non generic version
+	fmt.Fprintf(f, "\n// Eitherize%d converts a function with %d parameters returning a tuple into a function with %d parameters returning a [ReaderIOEither[R]]\n// The inverse function is [Uneitherize%d]\n", i, i, i, i)
+	fmt.Fprintf(f, "func Eitherize%d[F ~func(context.Context", i)
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, ", T%d", j)
+	}
+	fmt.Fprintf(f, ") (R, error)")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, ", T%d", j)
+	}
+	fmt.Fprintf(f, ", R any](f F) func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j)
+	}
+	fmt.Fprintf(f, ") ReaderIOEither[R] {\n")
+	fmt.Fprintf(f, "  return G.Eitherize%d[ReaderIOEither[R]](f)\n", i)
+	fmt.Fprintln(f, "}")
+
+	// generic version
+	fmt.Fprintf(fg, "\n// Eitherize%d converts a function with %d parameters returning a tuple into a function with %d parameters returning a [GRA]\n// The inverse function is [Uneitherize%d]\n", i, i, i, i)
+	fmt.Fprintf(fg, "func Eitherize%d[GRA ~func(context.Context) GIOA, F ~func(context.Context", i)
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(fg, ", T%d", j)
+	}
+	fmt.Fprintf(fg, ") (R, error), GIOA ~func() E.Either[error, R]")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(fg, ", T%d", j)
+	}
+	fmt.Fprintf(fg, ", R any](f F) func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(fg, ", ")
+		}
+		fmt.Fprintf(fg, "T%d", j)
+	}
+	fmt.Fprintf(fg, ") GRA {\n")
+	fmt.Fprintf(fg, "  return RE.Eitherize%d[GRA](f)\n", i)
+	fmt.Fprintln(fg, "}")
+}
+
+func generateContextReaderIOEitherUneitherize(f, fg *os.File, i int) {
+	// non generic version
+	fmt.Fprintf(f, "\n// Uneitherize%d converts a function with %d parameters returning a [ReaderIOEither[R]] into a function with %d parameters returning a tuple.\n// The first parameter is considered to be the [context.Context].\n", i, i+1, i)
+	fmt.Fprintf(f, "func Uneitherize%d[F ~func(", i)
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j)
+	}
+	fmt.Fprintf(f, ") ReaderIOEither[R]")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, ", T%d", j)
+	}
+	fmt.Fprintf(f, ", R any](f F) func(context.Context")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, ", T%d", j)
+	}
+	fmt.Fprintf(f, ") (R, error) {\n")
+	fmt.Fprintf(f, "  return G.Uneitherize%d[ReaderIOEither[R]", i)
+
+	fmt.Fprintf(f, ", func(context.Context")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, ", T%d", j)
+	}
+	fmt.Fprintf(f, ")(R, error)](f)\n")
+	fmt.Fprintln(f, "}")
+
+	// generic version
+	fmt.Fprintf(fg, "\n// Uneitherize%d converts a function with %d parameters returning a [GRA] into a function with %d parameters returning a tuple.\n// The first parameter is considered to be the [context.Context].\n", i, i, i)
+	fmt.Fprintf(fg, "func Uneitherize%d[GRA ~func(context.Context) GIOA, F ~func(context.Context", i)
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(fg, ", T%d", j)
+	}
+	fmt.Fprintf(fg, ") (R, error), GIOA ~func() E.Either[error, R]")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(fg, ", T%d", j)
+	}
+	fmt.Fprintf(fg, ", R any](f func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(fg, ", ")
+		}
+		fmt.Fprintf(fg, "T%d", j)
+	}
+	fmt.Fprintf(fg, ") GRA) F {\n")
+
+	fmt.Fprintf(fg, "  return func(c context.Context")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(fg, ", t%d T%d", j, j)
+	}
+	fmt.Fprintf(fg, ") (R, error) {\n")
+	fmt.Fprintf(fg, "    return E.UnwrapError(f(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(fg, ", ")
+		}
+		fmt.Fprintf(fg, "t%d", j)
+	}
+	fmt.Fprintf(fg, ")(c)())\n")
+	fmt.Fprintf(fg, "  }\n")
+	fmt.Fprintf(fg, "}\n")
+}
+
+func nonGenericContextReaderIOEither(param string) string {
+	return fmt.Sprintf("ReaderIOEither[%s]", param)
+}
+
+var extrasContextReaderIOEither = A.Empty[string]()
+
+func generateContextReaderIOEitherSequenceT(f *os.File, i int) {
+	generateGenericSequenceT("", nonGenericContextReaderIOEither, extrasContextReaderIOEither)(f, i)
+	generateGenericSequenceT("Seq", nonGenericContextReaderIOEither, extrasContextReaderIOEither)(f, i)
+	generateGenericSequenceT("Par", nonGenericContextReaderIOEither, extrasContextReaderIOEither)(f, i)
+}
+
+func generateContextReaderIOEitherSequenceTuple(f *os.File, i int) {
+	generateGenericSequenceTuple("", nonGenericContextReaderIOEither, extrasContextReaderIOEither)(f, i)
+	generateGenericSequenceTuple("Seq", nonGenericContextReaderIOEither, extrasContextReaderIOEither)(f, i)
+	generateGenericSequenceTuple("Par", nonGenericContextReaderIOEither, extrasContextReaderIOEither)(f, i)
+}
+
+func generateContextReaderIOEitherTraverseTuple(f *os.File, i int) {
+	generateGenericTraverseTuple("", nonGenericContextReaderIOEither, extrasContextReaderIOEither)(f, i)
+	generateGenericTraverseTuple("Seq", nonGenericContextReaderIOEither, extrasContextReaderIOEither)(f, i)
+	generateGenericTraverseTuple("Par", nonGenericContextReaderIOEither, extrasContextReaderIOEither)(f, i)
+}
+
+func generateContextReaderIOEitherHelpers(filename string, count int) error {
+	dir, err := os.Getwd()
+	if err != nil {
+		return err
+	}
+	absDir, err := filepath.Abs(dir)
+	if err != nil {
+		return err
+	}
+	pkg := filepath.Base(absDir)
+	f, err := os.Create(filepath.Clean(filename))
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	// construct subdirectory
+	genFilename := filepath.Join("generic", filename)
+	err = os.MkdirAll("generic", os.ModePerm)
+	if err != nil {
+		return err
+	}
+	fg, err := os.Create(filepath.Clean(genFilename))
+	if err != nil {
+		return err
+	}
+	defer fg.Close()
+
+	// log
+	log.Printf("Generating code in [%s] for package [%s] with [%d] repetitions ...", filename, pkg, count)
+
+	writePackage(f, pkg)
+
+	fmt.Fprintf(f, `
+import (
+	"context"
+
+	G "github.com/IBM/fp-go/v2/context/%s/generic"
+	"github.com/IBM/fp-go/v2/internal/apply"
+	"github.com/IBM/fp-go/v2/tuple"
+)
+`, pkg)
+
+	writePackage(fg, "generic")
+
+	fmt.Fprintf(fg, `
+import (
+	"context"
+
+	E "github.com/IBM/fp-go/v2/either"
+	RE "github.com/IBM/fp-go/v2/readerioeither/generic"
+)
+`)
+
+	generateContextReaderIOEitherEitherize(f, fg, 0)
+	generateContextReaderIOEitherUneitherize(f, fg, 0)
+
+	for i := 1; i <= count; i++ {
+		// eitherize
+		generateContextReaderIOEitherEitherize(f, fg, i)
+		generateContextReaderIOEitherUneitherize(f, fg, i)
+		// sequenceT
+		generateContextReaderIOEitherSequenceT(f, i)
+		// sequenceTuple
+		generateContextReaderIOEitherSequenceTuple(f, i)
+		// traverseTuple
+		generateContextReaderIOEitherTraverseTuple(f, i)
+	}
+
+	return nil
+}
+
+func ContextReaderIOEitherCommand() *C.Command {
+	return &C.Command{
+		Name:  "contextreaderioeither",
+		Usage: "generate code for ContextReaderIOEither",
+		Flags: []C.Flag{
+			flagCount,
+			flagFilename,
+		},
+		Action: func(ctx *C.Context) error {
+			return generateContextReaderIOEitherHelpers(
+				ctx.String(keyFilename),
+				ctx.Int(keyCount),
+			)
+		},
+	}
+}

v2/cli/di.go

@@ -0,0 +1,231 @@
+// 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 cli
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"time"
+
+	C "github.com/urfave/cli/v2"
+)
+
+func generateMakeProvider(f *os.File, i int) {
+	// non generic version
+	fmt.Fprintf(f, "\n// MakeProvider%d creates a [DIE.Provider] for an [InjectionToken] from a function with %d dependencies\n", i, i)
+	fmt.Fprintf(f, "func MakeProvider%d[", i)
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j+1)
+	}
+	fmt.Fprintf(f, " any, R any](\n")
+	fmt.Fprintf(f, "  token InjectionToken[R],\n")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, "  d%d Dependency[T%d],\n", j+1, j+1)
+	}
+	fmt.Fprintf(f, "  f func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j+1)
+	}
+	fmt.Fprintf(f, ") IOE.IOEither[error, R],\n")
+	fmt.Fprintf(f, ") DIE.Provider {\n")
+	fmt.Fprint(f, "  return DIE.MakeProvider(\n")
+	fmt.Fprint(f, "    token,\n")
+	fmt.Fprintf(f, "    MakeProviderFactory%d(\n", i)
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, "      d%d,\n", j+1)
+	}
+	fmt.Fprint(f, "      f,\n")
+	fmt.Fprint(f, "  ))\n")
+	fmt.Fprintf(f, "}\n")
+}
+
+func generateMakeTokenWithDefault(f *os.File, i int) {
+	// non generic version
+	fmt.Fprintf(f, "\n// MakeTokenWithDefault%d creates an [InjectionToken] with a default implementation with %d dependencies\n", i, i)
+	fmt.Fprintf(f, "func MakeTokenWithDefault%d[", i)
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j+1)
+	}
+	fmt.Fprintf(f, " any, R any](\n")
+	fmt.Fprintf(f, "  name string,\n")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, "  d%d Dependency[T%d],\n", j+1, j+1)
+	}
+	fmt.Fprintf(f, "  f func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j+1)
+	}
+	fmt.Fprintf(f, ") IOE.IOEither[error, R],\n")
+	fmt.Fprintf(f, ") InjectionToken[R] {\n")
+	fmt.Fprintf(f, "  return MakeTokenWithDefault[R](name, MakeProviderFactory%d(\n", i)
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, "    d%d,\n", j+1)
+	}
+	fmt.Fprint(f, "    f,\n")
+	fmt.Fprint(f, "  ))\n")
+	fmt.Fprintf(f, "}\n")
+}
+
+func generateMakeProviderFactory(f *os.File, i int) {
+	// non generic version
+	fmt.Fprintf(f, "\n// MakeProviderFactory%d creates a [DIE.ProviderFactory] from a function with %d arguments and %d dependencies\n", i, i, i)
+	fmt.Fprintf(f, "func MakeProviderFactory%d[", i)
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j+1)
+	}
+	fmt.Fprintf(f, " any, R any](\n")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, "  d%d Dependency[T%d],\n", j+1, j+1)
+	}
+	fmt.Fprintf(f, "  f func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j+1)
+	}
+	fmt.Fprintf(f, ") IOE.IOEither[error, R],\n")
+	fmt.Fprintf(f, ") DIE.ProviderFactory {\n")
+	fmt.Fprint(f, "  return DIE.MakeProviderFactory(\n")
+	fmt.Fprint(f, "    A.From[DIE.Dependency](\n")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, "      d%d,\n", j+1)
+	}
+	fmt.Fprint(f, "    ),\n")
+	fmt.Fprintf(f, "    eraseProviderFactory%d(\n", i)
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, "      d%d,\n", j+1)
+	}
+	fmt.Fprint(f, "      f,\n")
+	fmt.Fprint(f, "    ),\n")
+	fmt.Fprint(f, "  )\n")
+	fmt.Fprintf(f, "}\n")
+}
+
+func generateEraseProviderFactory(f *os.File, i int) {
+	// non generic version
+	fmt.Fprintf(f, "\n// eraseProviderFactory%d creates a function that takes a variadic number of untyped arguments and from a function of %d strongly typed arguments and %d dependencies\n", i, i, i)
+	fmt.Fprintf(f, "func eraseProviderFactory%d[", i)
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j+1)
+	}
+	fmt.Fprintf(f, " any, R any](\n")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, "  d%d Dependency[T%d],\n", j+1, j+1)
+	}
+	fmt.Fprintf(f, "  f func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j+1)
+	}
+	fmt.Fprintf(f, ") IOE.IOEither[error, R]) func(params ...any) IOE.IOEither[error, any] {\n")
+	fmt.Fprintf(f, "  ft := eraseTuple(T.Tupled%d(f))\n", i)
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, "  t%d := lookupAt[T%d](%d, d%d)\n", j+1, j+1, j, j+1)
+	}
+	fmt.Fprint(f, "  return func(params ...any) IOE.IOEither[error, any] {\n")
+	fmt.Fprintf(f, "    return ft(E.SequenceT%d(\n", i)
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, "      t%d(params),\n", j+1)
+	}
+	fmt.Fprint(f, "    ))\n")
+	fmt.Fprint(f, "  }\n")
+	fmt.Fprintf(f, "}\n")
+}
+
+func generateDIHelpers(filename string, count int) error {
+	dir, err := os.Getwd()
+	if err != nil {
+		return err
+	}
+	absDir, err := filepath.Abs(dir)
+	if err != nil {
+		return err
+	}
+	pkg := filepath.Base(absDir)
+	f, err := os.Create(filepath.Clean(filename))
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	// log
+	log.Printf("Generating code in [%s] for package [%s] with [%d] repetitions ...", filename, pkg, count)
+
+	// some header
+	fmt.Fprintln(f, "// Code generated by go generate; DO NOT EDIT.")
+	fmt.Fprintln(f, "// This file was generated by robots at")
+	fmt.Fprintf(f, "// %s\n\n", time.Now())
+
+	fmt.Fprintf(f, "package %s\n\n", pkg)
+
+	fmt.Fprint(f, `
+import (
+	E "github.com/IBM/fp-go/v2/either"
+	IOE "github.com/IBM/fp-go/v2/ioeither"
+	T "github.com/IBM/fp-go/v2/tuple"
+	A "github.com/IBM/fp-go/v2/array"
+	DIE "github.com/IBM/fp-go/v2/di/erasure"
+)
+`)
+
+	for i := 1; i <= count; i++ {
+		generateEraseProviderFactory(f, i)
+		generateMakeProviderFactory(f, i)
+		generateMakeTokenWithDefault(f, i)
+		generateMakeProvider(f, i)
+	}
+
+	return nil
+}
+
+func DICommand() *C.Command {
+	return &C.Command{
+		Name:  "di",
+		Usage: "generate code for the dependency injection package",
+		Flags: []C.Flag{
+			flagCount,
+			flagFilename,
+		},
+		Action: func(ctx *C.Context) error {
+			return generateDIHelpers(
+				ctx.String(keyFilename),
+				ctx.Int(keyCount),
+			)
+		},
+	}
+}

v2/cli/either.go

@@ -0,0 +1,200 @@
+// 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 cli
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"time"
+
+	C "github.com/urfave/cli/v2"
+)
+
+func eitherHKT(typeE string) func(typeA string) string {
+	return func(typeA string) string {
+		return fmt.Sprintf("Either[%s, %s]", typeE, typeA)
+	}
+}
+
+func generateEitherTraverseTuple(f *os.File, i int) {
+	generateTraverseTuple1(eitherHKT("E"), "E")(f, i)
+}
+
+func generateEitherSequenceTuple(f *os.File, i int) {
+	generateSequenceTuple1(eitherHKT("E"), "E")(f, i)
+}
+
+func generateEitherSequenceT(f *os.File, i int) {
+	generateSequenceT1(eitherHKT("E"), "E")(f, i)
+}
+
+func generateUneitherize(f *os.File, i int) {
+	// Create the optionize version
+	fmt.Fprintf(f, "\n// Uneitherize%d converts a function with %d parameters returning an Either into a function with %d parameters returning a tuple\n// The inverse function is [Eitherize%d]\n", i, i, i, i)
+	fmt.Fprintf(f, "func Uneitherize%d[F ~func(", i)
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j)
+	}
+	fmt.Fprintf(f, ") Either[error, R]")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, ", T%d", j)
+	}
+	fmt.Fprintf(f, ", R any](f F) func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j)
+	}
+	fmt.Fprintf(f, ") (R, error) {\n")
+	fmt.Fprintf(f, "  return func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "t%d T%d", j, j)
+	}
+	fmt.Fprintf(f, ") (R, error) {\n")
+	fmt.Fprintf(f, "    return UnwrapError(f(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "t%d", j)
+	}
+	fmt.Fprintln(f, "))")
+	fmt.Fprintln(f, "  }")
+	fmt.Fprintln(f, "}")
+}
+
+func generateEitherize(f *os.File, i int) {
+	// Create the optionize version
+	fmt.Fprintf(f, "\n// Eitherize%d converts a function with %d parameters returning a tuple into a function with %d parameters returning an Either\n// The inverse function is [Uneitherize%d]\n", i, i, i, i)
+	fmt.Fprintf(f, "func Eitherize%d[F ~func(", i)
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j)
+	}
+	fmt.Fprintf(f, ") (R, error)")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, ", T%d", j)
+	}
+	fmt.Fprintf(f, ", R any](f F) func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j)
+	}
+	fmt.Fprintf(f, ") Either[error, R] {\n")
+	fmt.Fprintf(f, "  return func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "t%d T%d", j, j)
+	}
+	fmt.Fprintf(f, ") Either[error, R] {\n")
+	fmt.Fprintf(f, "    return TryCatchError(f(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "t%d", j)
+	}
+	fmt.Fprintln(f, "))")
+	fmt.Fprintln(f, "  }")
+	fmt.Fprintln(f, "}")
+}
+
+func generateEitherHelpers(filename string, count int) error {
+	dir, err := os.Getwd()
+	if err != nil {
+		return err
+	}
+	absDir, err := filepath.Abs(dir)
+	if err != nil {
+		return err
+	}
+	pkg := filepath.Base(absDir)
+	f, err := os.Create(filepath.Clean(filename))
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	// log
+	log.Printf("Generating code in [%s] for package [%s] with [%d] repetitions ...", filename, pkg, count)
+
+	// some header
+	fmt.Fprintln(f, "// Code generated by go generate; DO NOT EDIT.")
+	fmt.Fprintln(f, "// This file was generated by robots at")
+	fmt.Fprintf(f, "// %s\n\n", time.Now())
+
+	fmt.Fprintf(f, "package %s\n\n", pkg)
+
+	fmt.Fprintf(f, `
+import (
+	A "github.com/IBM/fp-go/v2/internal/apply"
+	T "github.com/IBM/fp-go/v2/tuple"
+)
+`)
+
+	// zero level functions
+
+	// optionize
+	generateEitherize(f, 0)
+	// unoptionize
+	generateUneitherize(f, 0)
+
+	for i := 1; i <= count; i++ {
+		// optionize
+		generateEitherize(f, i)
+		// unoptionize
+		generateUneitherize(f, i)
+		// sequenceT
+		generateEitherSequenceT(f, i)
+		// sequenceTuple
+		generateEitherSequenceTuple(f, i)
+		// traverseTuple
+		generateEitherTraverseTuple(f, i)
+	}
+
+	return nil
+}
+
+func EitherCommand() *C.Command {
+	return &C.Command{
+		Name:  "either",
+		Usage: "generate code for Either",
+		Flags: []C.Flag{
+			flagCount,
+			flagFilename,
+		},
+		Action: func(ctx *C.Context) error {
+			return generateEitherHelpers(
+				ctx.String(keyFilename),
+				ctx.Int(keyCount),
+			)
+		},
+	}
+}

v2/cli/header.go

@@ -0,0 +1,31 @@
+// 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 cli
+
+import (
+	"fmt"
+	"os"
+	"time"
+)
+
+func writePackage(f *os.File, pkg string) {
+	// print package
+	fmt.Fprintf(f, "package %s\n\n", pkg)
+	// some header
+	fmt.Fprintln(f, "// Code generated by go generate; DO NOT EDIT.")
+	fmt.Fprintln(f, "// This file was generated by robots at")
+	fmt.Fprintf(f, "// %s\n\n", time.Now())
+}

v2/cli/identity.go

@@ -0,0 +1,103 @@
+// 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 cli
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"time"
+
+	C "github.com/urfave/cli/v2"
+)
+
+func identityHKT(typeA string) string {
+	return typeA
+}
+
+func generateIdentityTraverseTuple(f *os.File, i int) {
+	generateTraverseTuple1(identityHKT, "")(f, i)
+}
+
+func generateIdentitySequenceTuple(f *os.File, i int) {
+	generateSequenceTuple1(identityHKT, "")(f, i)
+}
+
+func generateIdentitySequenceT(f *os.File, i int) {
+	generateSequenceT1(identityHKT, "")(f, i)
+}
+
+func generateIdentityHelpers(filename string, count int) error {
+	dir, err := os.Getwd()
+	if err != nil {
+		return err
+	}
+	absDir, err := filepath.Abs(dir)
+	if err != nil {
+		return err
+	}
+	pkg := filepath.Base(absDir)
+	f, err := os.Create(filepath.Clean(filename))
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	// log
+	log.Printf("Generating code in [%s] for package [%s] with [%d] repetitions ...", filename, pkg, count)
+
+	// some header
+	fmt.Fprintln(f, "// Code generated by go generate; DO NOT EDIT.")
+	fmt.Fprintln(f, "// This file was generated by robots at")
+	fmt.Fprintf(f, "// %s\n\n", time.Now())
+
+	fmt.Fprintf(f, "package %s\n\n", pkg)
+
+	fmt.Fprintf(f, `
+import (
+	A "github.com/IBM/fp-go/v2/internal/apply"
+	T "github.com/IBM/fp-go/v2/tuple"
+)
+`)
+
+	for i := 1; i <= count; i++ {
+		// sequenceT
+		generateIdentitySequenceT(f, i)
+		// sequenceTuple
+		generateIdentitySequenceTuple(f, i)
+		// traverseTuple
+		generateIdentityTraverseTuple(f, i)
+	}
+
+	return nil
+}
+
+func IdentityCommand() *C.Command {
+	return &C.Command{
+		Name:  "identity",
+		Usage: "generate code for Identity",
+		Flags: []C.Flag{
+			flagCount,
+			flagFilename,
+		},
+		Action: func(ctx *C.Context) error {
+			return generateIdentityHelpers(
+				ctx.String(keyFilename),
+				ctx.Int(keyCount),
+			)
+		},
+	}
+}

v2/cli/io.go

@@ -0,0 +1,112 @@
+// 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 cli
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"time"
+
+	A "github.com/IBM/fp-go/v2/array"
+	C "github.com/urfave/cli/v2"
+)
+
+func nonGenericIO(param string) string {
+	return fmt.Sprintf("IO[%s]", param)
+}
+
+var extrasIO = A.Empty[string]()
+
+func generateIOSequenceT(f *os.File, i int) {
+	generateGenericSequenceT("", nonGenericIO, extrasIO)(f, i)
+	generateGenericSequenceT("Seq", nonGenericIO, extrasIO)(f, i)
+	generateGenericSequenceT("Par", nonGenericIO, extrasIO)(f, i)
+}
+
+func generateIOSequenceTuple(f *os.File, i int) {
+	generateGenericSequenceTuple("", nonGenericIO, extrasIO)(f, i)
+	generateGenericSequenceTuple("Seq", nonGenericIO, extrasIO)(f, i)
+	generateGenericSequenceTuple("Par", nonGenericIO, extrasIO)(f, i)
+}
+
+func generateIOTraverseTuple(f *os.File, i int) {
+	generateGenericTraverseTuple("", nonGenericIO, extrasIO)(f, i)
+	generateGenericTraverseTuple("Seq", nonGenericIO, extrasIO)(f, i)
+	generateGenericTraverseTuple("Par", nonGenericIO, extrasIO)(f, i)
+}
+
+func generateIOHelpers(filename string, count int) error {
+	dir, err := os.Getwd()
+	if err != nil {
+		return err
+	}
+	absDir, err := filepath.Abs(dir)
+	if err != nil {
+		return err
+	}
+	pkg := filepath.Base(absDir)
+	f, err := os.Create(filepath.Clean(filename))
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	// log
+	log.Printf("Generating code in [%s] for package [%s] with [%d] repetitions ...", filename, pkg, count)
+
+	// some header
+	fmt.Fprintln(f, "// Code generated by go generate; DO NOT EDIT.")
+	fmt.Fprintln(f, "// This file was generated by robots at")
+	fmt.Fprintf(f, "// %s\n\n", time.Now())
+
+	fmt.Fprintf(f, "package %s\n\n", pkg)
+
+	fmt.Fprintf(f, `
+import (
+	"github.com/IBM/fp-go/v2/tuple"
+	"github.com/IBM/fp-go/v2/internal/apply"
+)
+`)
+
+	for i := 1; i <= count; i++ {
+		// sequenceT
+		generateIOSequenceT(f, i)
+		// sequenceTuple
+		generateIOSequenceTuple(f, i)
+		// traverseTuple
+		generateIOTraverseTuple(f, i)
+	}
+
+	return nil
+}
+
+func IOCommand() *C.Command {
+	return &C.Command{
+		Name:  "io",
+		Usage: "generate code for IO",
+		Flags: []C.Flag{
+			flagCount,
+			flagFilename,
+		},
+		Action: func(ctx *C.Context) error {
+			return generateIOHelpers(
+				ctx.String(keyFilename),
+				ctx.Int(keyCount),
+			)
+		},
+	}
+}

v2/cli/ioeither.go

@@ -0,0 +1,283 @@
+// 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 cli
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"time"
+
+	A "github.com/IBM/fp-go/v2/array"
+	C "github.com/urfave/cli/v2"
+)
+
+// [GA ~func() ET.Either[E, A], GB ~func() ET.Either[E, B], GTAB ~func() ET.Either[E, T.Tuple2[A, B]], E, A, B any](a GA, b GB) GTAB {
+
+func nonGenericIOEither(param string) string {
+	return fmt.Sprintf("IOEither[E, %s]", param)
+}
+
+var extrasIOEither = A.From("E")
+
+func generateIOEitherSequenceT(f, fg *os.File, i int) {
+	generateGenericSequenceT("", nonGenericIOEither, extrasIOEither)(f, i)
+	generateGenericSequenceT("Seq", nonGenericIOEither, extrasIOEither)(f, i)
+	generateGenericSequenceT("Par", nonGenericIOEither, extrasIOEither)(f, i)
+}
+
+func generateIOEitherSequenceTuple(f, fg *os.File, i int) {
+	generateGenericSequenceTuple("", nonGenericIOEither, extrasIOEither)(f, i)
+	generateGenericSequenceTuple("Seq", nonGenericIOEither, extrasIOEither)(f, i)
+	generateGenericSequenceTuple("Par", nonGenericIOEither, extrasIOEither)(f, i)
+}
+
+func generateIOEitherTraverseTuple(f, fg *os.File, i int) {
+	generateGenericTraverseTuple("", nonGenericIOEither, extrasIOEither)(f, i)
+	generateGenericTraverseTuple("Seq", nonGenericIOEither, extrasIOEither)(f, i)
+	generateGenericTraverseTuple("Par", nonGenericIOEither, extrasIOEither)(f, i)
+}
+
+func generateIOEitherUneitherize(f, fg *os.File, i int) {
+	// non generic version
+	fmt.Fprintf(f, "\n// Uneitherize%d converts a function with %d parameters returning a tuple into a function with %d parameters returning a [IOEither[error, R]]\n", i, i+1, i)
+	fmt.Fprintf(f, "func Uneitherize%d[F ~func(", i)
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j+1)
+	}
+	fmt.Fprintf(f, ") IOEither[error, R]")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, ", T%d", j+1)
+	}
+	fmt.Fprintf(f, ", R any](f F) func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j+1)
+	}
+	fmt.Fprintf(f, ") (R, error) {\n")
+	fmt.Fprintf(f, "  return G.Uneitherize%d[IOEither[error, R]](f)\n", i)
+	fmt.Fprintln(f, "}")
+
+	// generic version
+	fmt.Fprintf(fg, "\n// Uneitherize%d converts a function with %d parameters returning a tuple into a function with %d parameters returning a [GIOA]\n", i, i, i)
+	fmt.Fprintf(fg, "func Uneitherize%d[GIOA ~func() ET.Either[error, R], GTA ~func(", i)
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(fg, ", ")
+		}
+		fmt.Fprintf(fg, "T%d", j+1)
+	}
+	fmt.Fprintf(fg, ") GIOA")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(fg, ", T%d", j+1)
+	}
+	fmt.Fprintf(fg, ", R any](f GTA) func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(fg, ", ")
+		}
+		fmt.Fprintf(fg, "T%d", j+1)
+	}
+	fmt.Fprintf(fg, ") (R, error) {\n")
+	fmt.Fprintf(fg, "  return func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(fg, ", ")
+		}
+		fmt.Fprintf(fg, "t%d T%d", j+1, j+1)
+	}
+	fmt.Fprintf(fg, ") (R, error) {\n")
+	fmt.Fprintf(fg, "    return ET.Unwrap(f(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(fg, ", ")
+		}
+		fmt.Fprintf(fg, "t%d", j+1)
+	}
+	fmt.Fprintf(fg, ")())\n")
+	fmt.Fprintf(fg, "  }\n")
+	fmt.Fprintf(fg, "}\n")
+}
+
+func generateIOEitherEitherize(f, fg *os.File, i int) {
+	// non generic version
+	fmt.Fprintf(f, "\n// Eitherize%d converts a function with %d parameters returning a tuple into a function with %d parameters returning a [IOEither[error, R]]\n", i, i+1, i)
+	fmt.Fprintf(f, "func Eitherize%d[F ~func(", i)
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j+1)
+	}
+	fmt.Fprintf(f, ") (R, error)")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, ", T%d", j+1)
+	}
+	fmt.Fprintf(f, ", R any](f F) func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j+1)
+	}
+	fmt.Fprintf(f, ") IOEither[error, R] {\n")
+	fmt.Fprintf(f, "  return G.Eitherize%d[IOEither[error, R]](f)\n", i)
+	fmt.Fprintln(f, "}")
+
+	// generic version
+	fmt.Fprintf(fg, "\n// Eitherize%d converts a function with %d parameters returning a tuple into a function with %d parameters returning a [GIOA]\n", i, i, i)
+	fmt.Fprintf(fg, "func Eitherize%d[GIOA ~func() ET.Either[error, R], F ~func(", i)
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(fg, ", ")
+		}
+		fmt.Fprintf(fg, "T%d", j+1)
+	}
+	fmt.Fprintf(fg, ") (R, error)")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(fg, ", T%d", j+1)
+	}
+	fmt.Fprintf(fg, ", R any](f F) func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(fg, ", ")
+		}
+		fmt.Fprintf(fg, "T%d", j+1)
+	}
+	fmt.Fprintf(fg, ") GIOA {\n")
+	fmt.Fprintf(fg, "  e := ET.Eitherize%d(f)\n", i)
+	fmt.Fprintf(fg, "  return func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(fg, ", ")
+		}
+		fmt.Fprintf(fg, "t%d T%d", j+1, j+1)
+	}
+	fmt.Fprintf(fg, ") GIOA {\n")
+	fmt.Fprintf(fg, "    return func() ET.Either[error, R] {\n")
+	fmt.Fprintf(fg, "      return e(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(fg, ", ")
+		}
+		fmt.Fprintf(fg, "t%d", j+1)
+	}
+	fmt.Fprintf(fg, ")\n")
+	fmt.Fprintf(fg, "    }}\n")
+	fmt.Fprintf(fg, "}\n")
+}
+
+func generateIOEitherHelpers(filename string, count int) error {
+	dir, err := os.Getwd()
+	if err != nil {
+		return err
+	}
+	absDir, err := filepath.Abs(dir)
+	if err != nil {
+		return err
+	}
+	pkg := filepath.Base(absDir)
+	f, err := os.Create(filepath.Clean(filename))
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	// construct subdirectory
+	genFilename := filepath.Join("generic", filename)
+	err = os.MkdirAll("generic", os.ModePerm)
+	if err != nil {
+		return err
+	}
+	fg, err := os.Create(filepath.Clean(genFilename))
+	if err != nil {
+		return err
+	}
+	defer fg.Close()
+
+	// log
+	log.Printf("Generating code in [%s] for package [%s] with [%d] repetitions ...", filename, pkg, count)
+
+	// some header
+	fmt.Fprintln(f, "// Code generated by go generate; DO NOT EDIT.")
+	fmt.Fprintln(f, "// This file was generated by robots at")
+	fmt.Fprintf(f, "// %s\n\n", time.Now())
+
+	fmt.Fprintf(f, "package %s\n\n", pkg)
+
+	fmt.Fprintf(f, `
+import (
+	G "github.com/IBM/fp-go/v2/%s/generic"	
+	"github.com/IBM/fp-go/v2/internal/apply"
+	"github.com/IBM/fp-go/v2/tuple"
+)
+`, pkg)
+
+	// some header
+	fmt.Fprintln(fg, "// Code generated by go generate; DO NOT EDIT.")
+	fmt.Fprintln(fg, "// This file was generated by robots at")
+	fmt.Fprintf(fg, "// %s\n", time.Now())
+
+	fmt.Fprintf(fg, "package generic\n\n")
+
+	fmt.Fprintf(fg, `
+import (
+	ET "github.com/IBM/fp-go/v2/either"
+)
+`)
+
+	// eitherize
+	generateIOEitherEitherize(f, fg, 0)
+	// uneitherize
+	generateIOEitherUneitherize(f, fg, 0)
+
+	for i := 1; i <= count; i++ {
+		// eitherize
+		generateIOEitherEitherize(f, fg, i)
+		// uneitherize
+		generateIOEitherUneitherize(f, fg, i)
+		// sequenceT
+		generateIOEitherSequenceT(f, fg, i)
+		// sequenceTuple
+		generateIOEitherSequenceTuple(f, fg, i)
+		// traverseTuple
+		generateIOEitherTraverseTuple(f, fg, i)
+	}
+
+	return nil
+}
+
+func IOEitherCommand() *C.Command {
+	return &C.Command{
+		Name:  "ioeither",
+		Usage: "generate code for IOEither",
+		Flags: []C.Flag{
+			flagCount,
+			flagFilename,
+		},
+		Action: func(ctx *C.Context) error {
+			return generateIOEitherHelpers(
+				ctx.String(keyFilename),
+				ctx.Int(keyCount),
+			)
+		},
+	}
+}

v2/cli/iooption.go

@@ -0,0 +1,117 @@
+// 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 cli
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"time"
+
+	A "github.com/IBM/fp-go/v2/array"
+	C "github.com/urfave/cli/v2"
+)
+
+func nonGenericIOOption(param string) string {
+	return fmt.Sprintf("IOOption[%s]", param)
+}
+
+func genericIOOption(param string) string {
+	return fmt.Sprintf("func() O.Option[%s]", param)
+}
+
+var extrasIOOption = A.Empty[string]()
+
+func generateIOOptionSequenceT(f *os.File, i int) {
+	generateGenericSequenceT("", nonGenericIOOption, extrasIOOption)(f, i)
+	generateGenericSequenceT("Seq", nonGenericIOOption, extrasIOOption)(f, i)
+	generateGenericSequenceT("Par", nonGenericIOOption, extrasIOOption)(f, i)
+}
+
+func generateIOOptionSequenceTuple(f *os.File, i int) {
+	generateGenericSequenceTuple("", nonGenericIOOption, extrasIOOption)(f, i)
+	generateGenericSequenceTuple("Seq", nonGenericIOOption, extrasIOOption)(f, i)
+	generateGenericSequenceTuple("Par", nonGenericIOOption, extrasIOOption)(f, i)
+}
+
+func generateIOOptionTraverseTuple(f *os.File, i int) {
+	generateGenericTraverseTuple("", nonGenericIOOption, extrasIOOption)(f, i)
+	generateGenericTraverseTuple("Seq", nonGenericIOOption, extrasIOOption)(f, i)
+	generateGenericTraverseTuple("Par", nonGenericIOOption, extrasIOOption)(f, i)
+}
+
+func generateIOOptionHelpers(filename string, count int) error {
+	dir, err := os.Getwd()
+	if err != nil {
+		return err
+	}
+	absDir, err := filepath.Abs(dir)
+	if err != nil {
+		return err
+	}
+	pkg := filepath.Base(absDir)
+	f, err := os.Create(filepath.Clean(filename))
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	// log
+	log.Printf("Generating code in [%s] for package [%s] with [%d] repetitions ...", filename, pkg, count)
+
+	// some header
+	fmt.Fprintln(f, "// Code generated by go generate; DO NOT EDIT.")
+	fmt.Fprintln(f, "// This file was generated by robots at")
+	fmt.Fprintf(f, "// %s\n\n", time.Now())
+
+	fmt.Fprintf(f, "package %s\n\n", pkg)
+
+	fmt.Fprintf(f, `
+import (
+	"github.com/IBM/fp-go/v2/tuple"
+	"github.com/IBM/fp-go/v2/internal/apply"
+)
+`)
+
+	for i := 1; i <= count; i++ {
+		// sequenceT
+		generateIOOptionSequenceT(f, i)
+		// sequenceTuple
+		generateIOOptionSequenceTuple(f, i)
+		// traverseTuple
+		generateIOOptionTraverseTuple(f, i)
+	}
+
+	return nil
+}
+
+func IOOptionCommand() *C.Command {
+	return &C.Command{
+		Name:  "iooption",
+		Usage: "generate code for IOOption",
+		Flags: []C.Flag{
+			flagCount,
+			flagFilename,
+		},
+		Action: func(ctx *C.Context) error {
+			return generateIOOptionHelpers(
+				ctx.String(keyFilename),
+				ctx.Int(keyCount),
+			)
+		},
+	}
+}

v2/cli/monad.go

@@ -0,0 +1,376 @@
+// 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 cli
+
+import (
+	"fmt"
+	"os"
+	"strings"
+)
+
+// Deprecated:
+func tupleType(name string) func(i int) string {
+	return func(i int) string {
+		var buf strings.Builder
+		buf.WriteString(fmt.Sprintf("T.Tuple%d[", i))
+		for j := 0; j < i; j++ {
+			if j > 0 {
+				buf.WriteString(", ")
+			}
+			buf.WriteString(fmt.Sprintf("%s%d", name, j+1))
+		}
+		buf.WriteString("]")
+
+		return buf.String()
+	}
+}
+
+func tupleTypePlain(name string) func(i int) string {
+	return func(i int) string {
+		var buf strings.Builder
+		buf.WriteString(fmt.Sprintf("tuple.Tuple%d[", i))
+		for j := 0; j < i; j++ {
+			if j > 0 {
+				buf.WriteString(", ")
+			}
+			buf.WriteString(fmt.Sprintf("%s%d", name, j+1))
+		}
+		buf.WriteString("]")
+
+		return buf.String()
+	}
+}
+
+func monadGenerateSequenceTNonGeneric(
+	hkt func(string) string,
+	fmap func(string, string) string,
+	fap func(string, string) string,
+) func(f *os.File, i int) {
+	return func(f *os.File, i int) {
+
+		tuple := tupleType("T")(i)
+
+		fmt.Fprintf(f, "SequenceT%d[", i)
+		for j := 0; j < i; j++ {
+			if j > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "T%d", j+1)
+		}
+		fmt.Fprintf(f, "](")
+		for j := 0; j < i; j++ {
+			if j > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "t%d %s", j+1, hkt(fmt.Sprintf("T%d", j+1)))
+		}
+		fmt.Fprintf(f, ") %s {", hkt(tuple))
+		// the actual apply callback
+		fmt.Fprintf(f, "  return apply.SequenceT%d(\n", i)
+		// map callback
+
+		curried := func(count int) string {
+			var buf strings.Builder
+			for j := count; j < i; j++ {
+				buf.WriteString(fmt.Sprintf("func(T%d)", j+1))
+			}
+			buf.WriteString(tuple)
+			return buf.String()
+		}
+
+		fmt.Fprintf(f, "    %s,\n", fmap("T1", curried(1)))
+		for j := 1; j < i; j++ {
+			fmt.Fprintf(f, "    %s,\n", fap(curried(j+1), fmt.Sprintf("T%d", j)))
+		}
+
+		for j := 0; j < i; j++ {
+			fmt.Fprintf(f, "    T%d,\n", j+1)
+		}
+
+		fmt.Fprintf(f, "  )\n")
+
+		fmt.Fprintf(f, "}\n")
+
+	}
+}
+
+func monadGenerateSequenceTGeneric(
+	hkt func(string) string,
+	fmap func(string, string) string,
+	fap func(string, string) string,
+) func(f *os.File, i int) {
+	return func(f *os.File, i int) {
+
+		tuple := tupleType("T")(i)
+
+		fmt.Fprintf(f, "SequenceT%d[", i)
+		for j := 0; j < i; j++ {
+			if j > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "T%d", j+1)
+		}
+		fmt.Fprintf(f, "](")
+		for j := 0; j < i; j++ {
+			if j > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "t%d %s", j+1, hkt(fmt.Sprintf("T%d", j+1)))
+		}
+		fmt.Fprintf(f, ") %s {", hkt(tuple))
+		// the actual apply callback
+		fmt.Fprintf(f, "  return apply.SequenceT%d(\n", i)
+		// map callback
+
+		curried := func(count int) string {
+			var buf strings.Builder
+			for j := count; j < i; j++ {
+				buf.WriteString(fmt.Sprintf("func(T%d)", j+1))
+			}
+			buf.WriteString(tuple)
+			return buf.String()
+		}
+
+		fmt.Fprintf(f, "    %s,\n", fmap("T1", curried(1)))
+		for j := 1; j < i; j++ {
+			fmt.Fprintf(f, "    %s,\n", fap(curried(j+1), fmt.Sprintf("T%d", j)))
+		}
+
+		for j := 0; j < i; j++ {
+			fmt.Fprintf(f, "    T%d,\n", j+1)
+		}
+
+		fmt.Fprintf(f, "  )\n")
+
+		fmt.Fprintf(f, "}\n")
+
+	}
+}
+
+func generateTraverseTuple1(
+	hkt func(string) string,
+	infix string) func(f *os.File, i int) {
+
+	return func(f *os.File, i int) {
+		tuple := tupleType("T")(i)
+
+		fmt.Fprintf(f, "\n// TraverseTuple%d converts a [Tuple%d] of [A] via transformation functions transforming [A] to [%s] into a [%s].\n", i, i, hkt("A"), hkt(fmt.Sprintf("Tuple%d", i)))
+		fmt.Fprintf(f, "func TraverseTuple%d[", i)
+		// functions
+		for j := 0; j < i; j++ {
+			if j > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "F%d ~func(A%d) %s", j+1, j+1, hkt(fmt.Sprintf("T%d", j+1)))
+		}
+		if infix != "" {
+			fmt.Fprintf(f, ", %s", infix)
+		}
+		// types
+		for j := 0; j < i; j++ {
+			fmt.Fprintf(f, ", A%d, T%d", j+1, j+1)
+		}
+		fmt.Fprintf(f, " any](")
+		for j := 0; j < i; j++ {
+			if j > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "f%d F%d", j+1, j+1)
+		}
+		fmt.Fprintf(f, ") func (T.Tuple%d[", i)
+		for j := 0; j < i; j++ {
+			if j > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "A%d", j+1)
+		}
+		fmt.Fprintf(f, "]) %s {\n", hkt(tuple))
+		fmt.Fprintf(f, "  return func(t T.Tuple%d[", i)
+		for j := 0; j < i; j++ {
+			if j > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "A%d", j+1)
+		}
+		fmt.Fprintf(f, "]) %s {\n", hkt(tuple))
+		fmt.Fprintf(f, "    return A.TraverseTuple%d(\n", i)
+		// map
+		fmt.Fprintf(f, "      Map[")
+		if infix != "" {
+			fmt.Fprintf(f, "%s, T1,", infix)
+		} else {
+			fmt.Fprintf(f, "T1,")
+		}
+		for j := 1; j < i; j++ {
+			fmt.Fprintf(f, " func(T%d)", j+1)
+		}
+		fmt.Fprintf(f, " %s],\n", tuple)
+		// applicatives
+		for j := 1; j < i; j++ {
+			fmt.Fprintf(f, "      Ap[")
+			for k := j + 1; k < i; k++ {
+				if k > j+1 {
+					fmt.Fprintf(f, " ")
+				}
+				fmt.Fprintf(f, "func(T%d)", k+1)
+			}
+			if j < i-1 {
+				fmt.Fprintf(f, " ")
+			}
+			fmt.Fprintf(f, "%s", tuple)
+			if infix != "" {
+				fmt.Fprintf(f, ", %s", infix)
+			}
+			fmt.Fprintf(f, ", T%d],\n", j+1)
+		}
+		for j := 0; j < i; j++ {
+			fmt.Fprintf(f, "      f%d,\n", j+1)
+		}
+		fmt.Fprintf(f, "      t,\n")
+		fmt.Fprintf(f, "    )\n")
+		fmt.Fprintf(f, "  }\n")
+		fmt.Fprintf(f, "}\n")
+	}
+}
+
+func generateSequenceTuple1(
+	hkt func(string) string,
+	infix string) func(f *os.File, i int) {
+
+	return func(f *os.File, i int) {
+
+		tuple := tupleType("T")(i)
+
+		fmt.Fprintf(f, "\n// SequenceTuple%d converts a [Tuple%d] of [%s] into an [%s].\n", i, i, hkt("T"), hkt(fmt.Sprintf("Tuple%d", i)))
+		fmt.Fprintf(f, "func SequenceTuple%d[", i)
+		if infix != "" {
+			fmt.Fprintf(f, "%s", infix)
+		}
+		for j := 0; j < i; j++ {
+			if infix != "" || j > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "T%d", j+1)
+		}
+		fmt.Fprintf(f, " any](t T.Tuple%d[", i)
+		for j := 0; j < i; j++ {
+			if j > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "%s", hkt(fmt.Sprintf("T%d", j+1)))
+		}
+		fmt.Fprintf(f, "]) %s {\n", hkt(tuple))
+		fmt.Fprintf(f, "  return A.SequenceTuple%d(\n", i)
+		// map
+		fmt.Fprintf(f, "    Map[")
+		if infix != "" {
+			fmt.Fprintf(f, "%s, T1,", infix)
+		} else {
+			fmt.Fprintf(f, "T1,")
+		}
+		for j := 1; j < i; j++ {
+			fmt.Fprintf(f, " func(T%d)", j+1)
+		}
+		fmt.Fprintf(f, " %s],\n", tuple)
+		// applicatives
+		for j := 1; j < i; j++ {
+			fmt.Fprintf(f, "    Ap[")
+			for k := j + 1; k < i; k++ {
+				if k > j+1 {
+					fmt.Fprintf(f, " ")
+				}
+				fmt.Fprintf(f, "func(T%d)", k+1)
+			}
+			if j < i-1 {
+				fmt.Fprintf(f, " ")
+			}
+			fmt.Fprintf(f, "%s", tuple)
+			if infix != "" {
+				fmt.Fprintf(f, ", %s", infix)
+			}
+			fmt.Fprintf(f, ", T%d],\n", j+1)
+		}
+		fmt.Fprintf(f, "    t,\n")
+		fmt.Fprintf(f, "  )\n")
+		fmt.Fprintf(f, "}\n")
+	}
+}
+
+func generateSequenceT1(
+	hkt func(string) string,
+	infix string) func(f *os.File, i int) {
+
+	return func(f *os.File, i int) {
+
+		tuple := tupleType("T")(i)
+
+		fmt.Fprintf(f, "\n// SequenceT%d converts %d parameters of [%s] into a [%s].\n", i, i, hkt("T"), hkt(fmt.Sprintf("Tuple%d", i)))
+		fmt.Fprintf(f, "func SequenceT%d[", i)
+		if infix != "" {
+			fmt.Fprintf(f, "%s", infix)
+		}
+		for j := 0; j < i; j++ {
+			if infix != "" || j > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "T%d", j+1)
+		}
+		fmt.Fprintf(f, " any](")
+		for j := 0; j < i; j++ {
+			if j > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "t%d %s", j+1, hkt(fmt.Sprintf("T%d", j+1)))
+		}
+		fmt.Fprintf(f, ") %s {\n", hkt(tuple))
+		fmt.Fprintf(f, "  return A.SequenceT%d(\n", i)
+		// map
+		fmt.Fprintf(f, "    Map[")
+		if infix != "" {
+			fmt.Fprintf(f, "%s, T1,", infix)
+		} else {
+			fmt.Fprintf(f, "T1,")
+		}
+		for j := 1; j < i; j++ {
+			fmt.Fprintf(f, " func(T%d)", j+1)
+		}
+		fmt.Fprintf(f, " %s],\n", tuple)
+		// applicatives
+		for j := 1; j < i; j++ {
+			fmt.Fprintf(f, "    Ap[")
+			for k := j + 1; k < i; k++ {
+				if k > j+1 {
+					fmt.Fprintf(f, " ")
+				}
+				fmt.Fprintf(f, "func(T%d)", k+1)
+			}
+			if j < i-1 {
+				fmt.Fprintf(f, " ")
+			}
+			fmt.Fprintf(f, "%s", tuple)
+			if infix != "" {
+				fmt.Fprintf(f, ", %s", infix)
+			}
+			fmt.Fprintf(f, ", T%d],\n", j+1)
+		}
+		for j := 0; j < i; j++ {
+			fmt.Fprintf(f, "    t%d,\n", j+1)
+		}
+		fmt.Fprintf(f, "  )\n")
+		fmt.Fprintf(f, "}\n")
+	}
+
+}

v2/cli/monad2.go

@@ -0,0 +1,413 @@
+// 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 cli
+
+import (
+	"fmt"
+	"os"
+
+	A "github.com/IBM/fp-go/v2/array"
+	F "github.com/IBM/fp-go/v2/function"
+	N "github.com/IBM/fp-go/v2/number"
+	S "github.com/IBM/fp-go/v2/string"
+)
+
+var (
+	concStrgs     = A.Monoid[string]().Concat
+	intercalStrgs = A.Intercalate(S.Monoid)
+	concAllStrgs  = A.ConcatAll(A.Monoid[string]())
+)
+
+func joinAll(middle string) func(all ...[]string) string {
+	ic := intercalStrgs(middle)
+	return func(all ...[]string) string {
+		return ic(concAllStrgs(all))
+	}
+}
+
+// Deprecated:
+func deprecatedGenerateGenericSequenceT(
+	nonGenericType func(string) string,
+	genericType func(string) string,
+	extra []string,
+) func(f, fg *os.File, i int) {
+	return func(f, fg *os.File, i int) {
+		// tuple
+		tuple := tupleType("T")(i)
+		// all types T
+		typesT := A.MakeBy(i, F.Flow2(
+			N.Inc[int],
+			S.Format[int]("T%d"),
+		))
+		// non generic version
+		fmt.Fprintf(f, "\n// SequenceT%d converts %d [%s] into a [%s]\n", i, i, nonGenericType("T"), nonGenericType(tuple))
+		fmt.Fprintf(f, "func SequenceT%d[%s any](\n", i, joinAll(", ")(extra, typesT))
+		for j := 0; j < i; j++ {
+			fmt.Fprintf(f, "  t%d %s,\n", j+1, nonGenericType(fmt.Sprintf("T%d", j+1)))
+		}
+		fmt.Fprintf(f, ") %s {\n", nonGenericType(tuple))
+		fmt.Fprintf(f, "  return G.SequenceT%d[\n", i)
+		fmt.Fprintf(f, "    %s,\n", nonGenericType(tuple))
+		for j := 0; j < i; j++ {
+			fmt.Fprintf(f, "    %s,\n", nonGenericType(fmt.Sprintf("T%d", j+1)))
+		}
+		fmt.Fprintf(f, "  ](")
+		for j := 0; j < i; j++ {
+			if j > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "t%d", j+1)
+		}
+		fmt.Fprintf(f, ")\n")
+		fmt.Fprintf(f, "}\n")
+
+		// generic version
+		fmt.Fprintf(fg, "\n// SequenceT%d converts %d [%s] into a [%s]\n", i, i, genericType("T"), genericType(tuple))
+		fmt.Fprintf(fg, "func SequenceT%d[\n", i)
+		fmt.Fprintf(fg, "  G_TUPLE%d ~%s,\n", i, genericType(tuple))
+		for j := 0; j < i; j++ {
+			fmt.Fprintf(fg, "  G_T%d ~%s, \n", j+1, genericType(fmt.Sprintf("T%d", j+1)))
+		}
+		fmt.Fprintf(fg, "  %s any](\n", joinAll(", ")(extra, typesT))
+		for j := 0; j < i; j++ {
+			fmt.Fprintf(fg, "  t%d G_T%d,\n", j+1, j+1)
+		}
+		fmt.Fprintf(fg, ")  G_TUPLE%d {\n", i)
+		fmt.Fprintf(fg, "  return A.SequenceT%d(\n", i)
+		// map call
+		var cio string
+		cb := generateNestedCallbacks(1, i)
+		if i > 1 {
+			cio = genericType(cb)
+		} else {
+			cio = fmt.Sprintf("G_TUPLE%d", i)
+		}
+		fmt.Fprintf(fg, "    Map[%s],\n", joinAll(", ")(A.From("G_T1", cio), extra, A.From("T1", cb)))
+		// the apply calls
+		for j := 1; j < i; j++ {
+			if j < i-1 {
+				cb := generateNestedCallbacks(j+1, i)
+				cio = genericType(cb)
+			} else {
+				cio = fmt.Sprintf("G_TUPLE%d", i)
+			}
+			fmt.Fprintf(fg, "    Ap[%s, %s, G_T%d],\n", cio, genericType(generateNestedCallbacks(j, i)), j+1)
+		}
+		// function parameters
+		for j := 0; j < i; j++ {
+			fmt.Fprintf(fg, "    t%d,\n", j+1)
+		}
+
+		fmt.Fprintf(fg, "  )\n")
+		fmt.Fprintf(fg, "}\n")
+	}
+}
+
+// Deprecated:
+func deprecatedGenerateGenericSequenceTuple(
+	nonGenericType func(string) string,
+	genericType func(string) string,
+	extra []string,
+) func(f, fg *os.File, i int) {
+	return func(f, fg *os.File, i int) {
+		// tuple
+		tuple := tupleType("T")(i)
+		// all types T
+		typesT := A.MakeBy(i, F.Flow2(
+			N.Inc[int],
+			S.Format[int]("T%d"),
+		))
+		// non generic version
+		fmt.Fprintf(f, "\n// SequenceTuple%d converts a [T.Tuple%d[%s]] into a [%s]\n", i, i, nonGenericType("T"), nonGenericType(tuple))
+		fmt.Fprintf(f, "func SequenceTuple%d[%s any](t T.Tuple%d[", i, joinAll(", ")(extra, typesT), i)
+		for j := 0; j < i; j++ {
+			if j > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "%s", nonGenericType(fmt.Sprintf("T%d", j+1)))
+		}
+		fmt.Fprintf(f, "]) %s {\n", nonGenericType(tuple))
+		fmt.Fprintf(f, "  return G.SequenceTuple%d[\n", i)
+		fmt.Fprintf(f, "    %s,\n", nonGenericType(tuple))
+		for j := 0; j < i; j++ {
+			fmt.Fprintf(f, "    %s,\n", nonGenericType(fmt.Sprintf("T%d", j+1)))
+		}
+		fmt.Fprintf(f, "  ](t)\n")
+		fmt.Fprintf(f, "}\n")
+
+		// generic version
+		fmt.Fprintf(fg, "\n// SequenceTuple%d converts a [T.Tuple%d[%s]] into a [%s]\n", i, i, genericType("T"), genericType(tuple))
+		fmt.Fprintf(fg, "func SequenceTuple%d[\n", i)
+		fmt.Fprintf(fg, "  G_TUPLE%d ~%s,\n", i, genericType(tuple))
+		for j := 0; j < i; j++ {
+			fmt.Fprintf(fg, "  G_T%d ~%s, \n", j+1, genericType(fmt.Sprintf("T%d", j+1)))
+		}
+		fmt.Fprintf(fg, "  %s any](t T.Tuple%d[", joinAll(", ")(extra, typesT), i)
+		for j := 0; j < i; j++ {
+			if j > 0 {
+				fmt.Fprintf(fg, ", ")
+			}
+			fmt.Fprintf(fg, "G_T%d", j+1)
+		}
+		fmt.Fprintf(fg, "])  G_TUPLE%d {\n", i)
+		fmt.Fprintf(fg, "  return A.SequenceTuple%d(\n", i)
+		// map call
+		var cio string
+		cb := generateNestedCallbacks(1, i)
+		if i > 1 {
+			cio = genericType(cb)
+		} else {
+			cio = fmt.Sprintf("G_TUPLE%d", i)
+		}
+		fmt.Fprintf(fg, "    Map[%s],\n", joinAll(", ")(A.From("G_T1", cio), extra, A.From("T1", cb)))
+		// the apply calls
+		for j := 1; j < i; j++ {
+			if j < i-1 {
+				cb := generateNestedCallbacks(j+1, i)
+				cio = genericType(cb)
+			} else {
+				cio = fmt.Sprintf("G_TUPLE%d", i)
+			}
+			fmt.Fprintf(fg, "    Ap[%s, %s, G_T%d],\n", cio, genericType(generateNestedCallbacks(j, i)), j+1)
+		}
+		// function parameters
+		fmt.Fprintf(fg, "    t)\n")
+		fmt.Fprintf(fg, "}\n")
+	}
+}
+
+// Deprecated:
+func deprecatedGenerateGenericTraverseTuple(
+	nonGenericType func(string) string,
+	genericType func(string) string,
+	extra []string,
+) func(f, fg *os.File, i int) {
+	return func(f, fg *os.File, i int) {
+		// tuple
+		tupleT := tupleType("T")(i)
+		tupleA := tupleType("A")(i)
+		// all types T
+		typesT := A.MakeBy(i, F.Flow2(
+			N.Inc[int],
+			S.Format[int]("T%d"),
+		))
+		// all types A
+		typesA := A.MakeBy(i, F.Flow2(
+			N.Inc[int],
+			S.Format[int]("A%d"),
+		))
+		// all function types
+		typesF := A.MakeBy(i, F.Flow2(
+			N.Inc[int],
+			func(j int) string {
+				return fmt.Sprintf("F%d ~func(A%d) %s", j, j, nonGenericType(fmt.Sprintf("T%d", j)))
+			},
+		))
+		// non generic version
+		fmt.Fprintf(f, "\n// TraverseTuple%d converts a [T.Tuple%d[%s]] into a [%s]\n", i, i, nonGenericType("T"), nonGenericType(tupleT))
+		fmt.Fprintf(f, "func TraverseTuple%d[%s any](", i, joinAll(", ")(typesF, extra, typesA, typesT))
+		for j := 0; j < i; j++ {
+			if j > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "f%d F%d", j+1, j+1)
+		}
+		fmt.Fprintf(f, ") func(%s) %s {\n", tupleA, nonGenericType(tupleT))
+		fmt.Fprintf(f, "  return G.TraverseTuple%d[%s](", i, nonGenericType(tupleT))
+		for j := 0; j < i; j++ {
+			if j > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "f%d", j+1)
+		}
+		fmt.Fprintf(f, ")\n")
+		fmt.Fprintf(f, "}\n")
+
+		// generic version
+		fmt.Fprintf(fg, "\n// TraverseTuple%d converts a [T.Tuple%d[%s]] into a [%s]\n", i, i, genericType("T"), genericType(tupleT))
+		fmt.Fprintf(fg, "func TraverseTuple%d[\n", i)
+		fmt.Fprintf(fg, "  G_TUPLE%d ~%s,\n", i, genericType(tupleT))
+		for j := 0; j < i; j++ {
+			fmt.Fprintf(fg, "  F%d ~func(A%d) G_T%d,\n", j+1, j+1, j+1)
+		}
+		for j := 0; j < i; j++ {
+			fmt.Fprintf(fg, "  G_T%d ~%s, \n", j+1, genericType(fmt.Sprintf("T%d", j+1)))
+		}
+		fmt.Fprintf(fg, "  %s any](", joinAll(", ")(extra, typesA, typesT))
+		for j := 0; j < i; j++ {
+			if j > 0 {
+				fmt.Fprintf(fg, ", ")
+			}
+			fmt.Fprintf(fg, "f%d F%d", j+1, j+1)
+		}
+		fmt.Fprintf(fg, ") func(%s) G_TUPLE%d {\n", tupleA, i)
+		fmt.Fprintf(fg, "  return func(t %s) G_TUPLE%d {\n", tupleA, i)
+		fmt.Fprintf(fg, "    return A.TraverseTuple%d(\n", i)
+		// map call
+		var cio string
+		cb := generateNestedCallbacks(1, i)
+		if i > 1 {
+			cio = genericType(cb)
+		} else {
+			cio = fmt.Sprintf("G_TUPLE%d", i)
+		}
+		fmt.Fprintf(fg, "    Map[%s],\n", joinAll(", ")(A.From("G_T1", cio), extra, A.From("T1", cb)))
+		// the apply calls
+		for j := 1; j < i; j++ {
+			if j < i-1 {
+				cb := generateNestedCallbacks(j+1, i)
+				cio = genericType(cb)
+			} else {
+				cio = fmt.Sprintf("G_TUPLE%d", i)
+			}
+			fmt.Fprintf(fg, "    Ap[%s, %s, G_T%d],\n", cio, genericType(generateNestedCallbacks(j, i)), j+1)
+		}
+		// function parameters
+		for j := 0; j < i; j++ {
+			fmt.Fprintf(fg, "    f%d,\n", j+1)
+		}
+		// tuple parameter
+		fmt.Fprintf(fg, "    t)\n")
+		fmt.Fprintf(fg, "   }\n")
+		fmt.Fprintf(fg, "}\n")
+	}
+}
+
+func generateGenericSequenceT(
+	suffix string,
+	nonGenericType func(string) string,
+	extra []string,
+) func(f *os.File, i int) {
+	return func(f *os.File, i int) {
+		// tuple
+		tuple := tupleTypePlain("T")(i)
+		// all types T
+		typesT := A.MakeBy(i, F.Flow2(
+			N.Inc[int],
+			S.Format[int]("T%d"),
+		))
+		// non generic version
+		fmt.Fprintf(f, "\n// Sequence%sT%d converts %d [%s] into a [%s]\n", suffix, i, i, nonGenericType("T"), nonGenericType(tuple))
+		fmt.Fprintf(f, "func Sequence%sT%d[%s any](\n", suffix, i, joinAll(", ")(extra, typesT))
+		for j := 0; j < i; j++ {
+			fmt.Fprintf(f, "  t%d %s,\n", j+1, nonGenericType(fmt.Sprintf("T%d", j+1)))
+		}
+		fmt.Fprintf(f, ") %s {\n", nonGenericType(tuple))
+		fmt.Fprintf(f, "  return apply.SequenceT%d(\n", i)
+		fmt.Fprintf(f, "    Map[%s],\n", joinAll(", ")(extra, A.From("T1", generateNestedCallbacksPlain(1, i))))
+
+		// the apply calls
+		for j := 2; j <= i; j++ {
+			fmt.Fprintf(f, "    Ap%s[%s],\n", suffix, joinAll(", ")(A.Of(generateNestedCallbacksPlain(j, i)), extra, A.Of(fmt.Sprintf("T%d", j))))
+		}
+		// function parameters
+		for j := 1; j <= i; j++ {
+			fmt.Fprintf(f, "    t%d,\n", j)
+		}
+
+		fmt.Fprintf(f, "  )\n")
+		fmt.Fprintf(f, "}\n")
+	}
+}
+
+func generateGenericSequenceTuple(
+	suffix string,
+	nonGenericType func(string) string,
+	extra []string,
+) func(f *os.File, i int) {
+	return func(f *os.File, i int) {
+		// tuple
+		tuple := tupleTypePlain("T")(i)
+		// all types T
+		typesT := A.MakeBy(i, F.Flow2(
+			N.Inc[int],
+			S.Format[int]("T%d"),
+		))
+		// non generic version
+		fmt.Fprintf(f, "\n// Sequence%sTuple%d converts a [tuple.Tuple%d[%s]] into a [%s]\n", suffix, i, i, nonGenericType("T"), nonGenericType(tuple))
+		fmt.Fprintf(f, "func Sequence%sTuple%d[%s any](t tuple.Tuple%d[", suffix, i, joinAll(", ")(extra, typesT), i)
+		for j := 0; j < i; j++ {
+			if j > 0 {
+				fmt.Fprintf(f, ", ")
+			}
+			fmt.Fprintf(f, "%s", nonGenericType(fmt.Sprintf("T%d", j+1)))
+		}
+		fmt.Fprintf(f, "]) %s {\n", nonGenericType(tuple))
+		fmt.Fprintf(f, "  return apply.SequenceTuple%d(\n", i)
+		fmt.Fprintf(f, "    Map[%s],\n", joinAll(", ")(extra, A.From("T1", generateNestedCallbacksPlain(1, i))))
+
+		// the apply calls
+		for j := 2; j <= i; j++ {
+			fmt.Fprintf(f, "    Ap%s[%s],\n", suffix, joinAll(", ")(A.Of(generateNestedCallbacksPlain(j, i)), extra, A.Of(fmt.Sprintf("T%d", j))))
+		}
+
+		// function parameters
+		fmt.Fprintf(f, "    t,\n")
+		// function parameters
+		fmt.Fprintf(f, "  )\n")
+		fmt.Fprintf(f, "}\n")
+	}
+}
+
+func generateGenericTraverseTuple(
+	suffix string,
+	nonGenericType func(string) string,
+	extra []string,
+) func(f *os.File, i int) {
+	return func(f *os.File, i int) {
+		// all types T
+		typesT := A.MakeBy(i, F.Flow2(
+			N.Inc[int],
+			S.Format[int]("T%d"),
+		))
+		// all types A
+		typesA := A.MakeBy(i, F.Flow2(
+			N.Inc[int],
+			S.Format[int]("A%d"),
+		))
+		// function types
+		typesF := A.MakeBy(i, func(j int) string {
+			return fmt.Sprintf("F%d ~func(A%d) %s", j+1, j+1, nonGenericType(fmt.Sprintf("T%d", j+1)))
+		})
+		paramF := A.MakeBy(i, func(j int) string {
+			return fmt.Sprintf("f%d F%d", j+1, j+1)
+		})
+		// return type
+		paramType := fmt.Sprintf("tuple.Tuple%d[%s]", i, joinAll(", ")(typesA))
+		returnType := nonGenericType(fmt.Sprintf("tuple.Tuple%d[%s]", i, joinAll(", ")(typesT)))
+		// non generic version
+		fmt.Fprintf(f, "\n// Traverse%sTuple%d converts a [%s] into a [%s]\n", suffix, i, paramType, returnType)
+		fmt.Fprintf(f, "func Traverse%sTuple%d[%s any](%s) func(%s) %s {\n", suffix, i, joinAll(", ")(extra, typesF, typesT, typesA), joinAll(", ")(paramF), paramType, returnType)
+		fmt.Fprintf(f, "  return func(t %s) %s {\n", paramType, returnType)
+		fmt.Fprintf(f, "    return apply.TraverseTuple%d(\n", i)
+		fmt.Fprintf(f, "      Map[%s],\n", joinAll(", ")(extra, A.From("T1", generateNestedCallbacksPlain(1, i))))
+
+		// the apply calls
+		for j := 2; j <= i; j++ {
+			fmt.Fprintf(f, "      Ap%s[%s],\n", suffix, joinAll(", ")(A.Of(generateNestedCallbacksPlain(j, i)), extra, A.Of(fmt.Sprintf("T%d", j))))
+		}
+		// the function parameters
+		for j := 1; j <= i; j++ {
+			fmt.Fprintf(f, "      f%d,\n", j)
+		}
+		// function parameters
+		fmt.Fprintf(f, "      t,\n")
+		// function parameters
+		fmt.Fprintf(f, "    )\n")
+		fmt.Fprintf(f, "  }\n")
+		fmt.Fprintf(f, "}\n")
+	}
+}

v2/cli/option.go

@@ -0,0 +1,210 @@
+// 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 cli
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"time"
+
+	C "github.com/urfave/cli/v2"
+)
+
+func optionHKT(typeA string) string {
+	return fmt.Sprintf("Option[%s]", typeA)
+}
+
+func generateOptionTraverseTuple(f *os.File, i int) {
+	generateTraverseTuple1(optionHKT, "")(f, i)
+}
+
+func generateOptionSequenceTuple(f *os.File, i int) {
+	generateSequenceTuple1(optionHKT, "")(f, i)
+}
+
+func generateOptionSequenceT(f *os.File, i int) {
+	generateSequenceT1(optionHKT, "")(f, i)
+}
+
+func generateOptionize(f *os.File, i int) {
+	// Create the optionize version
+	fmt.Fprintf(f, "\n// Optionize%d converts a function with %d parameters returning a tuple of a return value R and a boolean into a function with %d parameters returning an Option[R]\n", i, i, i)
+	fmt.Fprintf(f, "func Optionize%d[F ~func(", i)
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j)
+	}
+	fmt.Fprintf(f, ") (R, bool)")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, ", T%d", j)
+	}
+	fmt.Fprintf(f, ", R any](f F) func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j)
+	}
+	fmt.Fprintf(f, ") Option[R] {\n")
+	fmt.Fprintf(f, "  return func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "t%d T%d", j, j)
+	}
+	fmt.Fprintf(f, ") Option[R] {\n")
+	fmt.Fprintf(f, "    return optionize(func() (R, bool) {\n")
+	fmt.Fprintf(f, "      return f(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "t%d", j)
+	}
+	fmt.Fprintln(f, ")")
+	fmt.Fprintln(f, "    })")
+	fmt.Fprintln(f, "  }")
+	fmt.Fprintln(f, "}")
+}
+
+func generateUnoptionize(f *os.File, i int) {
+	// Create the optionize version
+	fmt.Fprintf(f, "\n// Unoptionize%d converts a function with %d parameters returning a tuple of a return value R and a boolean into a function with %d parameters returning an Option[R]\n", i, i, i)
+	fmt.Fprintf(f, "func Unoptionize%d[F ~func(", i)
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j)
+	}
+	fmt.Fprintf(f, ") Option[R]")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, ", T%d", j)
+	}
+	fmt.Fprintf(f, ", R any](f F) func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j)
+	}
+	fmt.Fprintf(f, ") (R, bool) {\n")
+	fmt.Fprintf(f, "  return func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "t%d T%d", j, j)
+	}
+	fmt.Fprintf(f, ") (R, bool) {\n")
+	fmt.Fprintf(f, "    return Unwrap(f(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "t%d", j)
+	}
+	fmt.Fprintln(f, "))")
+	fmt.Fprintln(f, "  }")
+	fmt.Fprintln(f, "}")
+}
+
+func generateOptionHelpers(filename string, count int) error {
+	dir, err := os.Getwd()
+	if err != nil {
+		return err
+	}
+	absDir, err := filepath.Abs(dir)
+	if err != nil {
+		return err
+	}
+	pkg := filepath.Base(absDir)
+	f, err := os.Create(filepath.Clean(filename))
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	// log
+	log.Printf("Generating code in [%s] for package [%s] with [%d] repetitions ...", filename, pkg, count)
+
+	// some header
+	fmt.Fprintln(f, "// Code generated by go generate; DO NOT EDIT.")
+	fmt.Fprintln(f, "// This file was generated by robots at")
+	fmt.Fprintf(f, "// %s\n\n", time.Now())
+
+	fmt.Fprintf(f, "package %s\n\n", pkg)
+
+	fmt.Fprintf(f, `
+import (
+	A "github.com/IBM/fp-go/v2/internal/apply"
+	T "github.com/IBM/fp-go/v2/tuple"
+)
+`)
+
+	// print out some helpers
+	fmt.Fprintf(f, `// optionize converts a nullary function to an option
+func optionize[R any](f func() (R, bool)) Option[R] {
+	if r, ok := f(); ok {
+		return Some(r)
+	}
+	return None[R]()
+}
+`)
+
+	// zero level functions
+
+	// optionize
+	generateOptionize(f, 0)
+	// unoptionize
+	generateUnoptionize(f, 0)
+
+	for i := 1; i <= count; i++ {
+		// optionize
+		generateOptionize(f, i)
+		// unoptionize
+		generateUnoptionize(f, i)
+		// sequenceT
+		generateOptionSequenceT(f, i)
+		// sequenceTuple
+		generateOptionSequenceTuple(f, i)
+		// traverseTuple
+		generateOptionTraverseTuple(f, i)
+	}
+
+	return nil
+}
+
+func OptionCommand() *C.Command {
+	return &C.Command{
+		Name:  "option",
+		Usage: "generate code for Option",
+		Flags: []C.Flag{
+			flagCount,
+			flagFilename,
+		},
+		Action: func(ctx *C.Context) error {
+			return generateOptionHelpers(
+				ctx.String(keyFilename),
+				ctx.Int(keyCount),
+			)
+		},
+	}
+}

v2/cli/pipe.go

@@ -0,0 +1,433 @@
+// 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 cli
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"time"
+
+	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)
+	fmt.Fprintf(f, "func Variadic%d[", i)
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j)
+	}
+	if i > 0 {
+		fmt.Fprintf(f, ", ")
+	}
+	fmt.Fprintf(f, "V, R any](f func(")
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j)
+	}
+	if i > 0 {
+		fmt.Fprintf(f, ", ")
+	}
+	fmt.Fprintf(f, "[]V) R) func(")
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j)
+	}
+	if i > 0 {
+		fmt.Fprintf(f, ", ")
+	}
+	fmt.Fprintf(f, "...V) R {\n")
+	fmt.Fprintf(f, "  return func(")
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "t%d T%d", j, j)
+	}
+	if i > 0 {
+		fmt.Fprintf(f, ", ")
+	}
+	fmt.Fprintf(f, "v ...V) R {\n")
+	fmt.Fprintf(f, "    return f(")
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "t%d", j)
+	}
+	if i > 0 {
+		fmt.Fprintf(f, ", ")
+	}
+	fmt.Fprintf(f, "v)\n")
+	fmt.Fprintf(f, "  }\n")
+
+	fmt.Fprintf(f, "}\n")
+}
+
+func generateUnvariadic(f *os.File, i int) {
+	// Create the nullary version
+	fmt.Fprintf(f, "\n// Unvariadic%d converts a function taking %d parameters and a final variadic argument into a function with %d parameters but a final slice argument\n", i, i, i)
+	fmt.Fprintf(f, "func Unvariadic%d[", i)
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j)
+	}
+	if i > 0 {
+		fmt.Fprintf(f, ", ")
+	}
+	fmt.Fprintf(f, "V, R any](f func(")
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j)
+	}
+	if i > 0 {
+		fmt.Fprintf(f, ", ")
+	}
+	fmt.Fprintf(f, "...V) R) func(")
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j)
+	}
+	if i > 0 {
+		fmt.Fprintf(f, ", ")
+	}
+	fmt.Fprintf(f, "[]V) R {\n")
+	fmt.Fprintf(f, "  return func(")
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "t%d T%d", j, j)
+	}
+	if i > 0 {
+		fmt.Fprintf(f, ", ")
+	}
+	fmt.Fprintf(f, "v []V) R {\n")
+	fmt.Fprintf(f, "    return f(")
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "t%d", j)
+	}
+	if i > 0 {
+		fmt.Fprintf(f, ", ")
+	}
+	fmt.Fprintf(f, "v...)\n")
+	fmt.Fprintf(f, "  }\n")
+
+	fmt.Fprintf(f, "}\n")
+}
+
+func generateNullary(f *os.File, i int) {
+	// Create the nullary version
+	fmt.Fprintf(f, "\n// Nullary%d creates a parameter less function from a parameter less function and %d functions. When executed the first parameter less function gets executed and then the result is piped through the remaining functions\n", i, i-1)
+	fmt.Fprintf(f, "func Nullary%d[F1 ~func() T1", i)
+	for j := 2; j <= i; j++ {
+		fmt.Fprintf(f, ", F%d ~func(T%d) T%d", j, j-1, j)
+	}
+	for j := 1; j <= i; j++ {
+		fmt.Fprintf(f, ", T%d", j)
+	}
+	fmt.Fprintf(f, " any](f1 F1")
+	for j := 2; j <= i; j++ {
+		fmt.Fprintf(f, ", f%d F%d", j, j)
+	}
+	fmt.Fprintf(f, ") func() T%d {\n", i)
+	fmt.Fprintf(f, "  return func() T%d {\n", i)
+	fmt.Fprintf(f, "    return Pipe%d(f1()", i-1)
+	for j := 2; j <= i; j++ {
+		fmt.Fprintf(f, ", f%d", j)
+	}
+	fmt.Fprintf(f, ")\n")
+	fmt.Fprintln(f, "  }")
+
+	fmt.Fprintln(f, "}")
+}
+
+func generateFlow(f *os.File, i int) {
+	// Create the flow version
+	fmt.Fprintf(f, "\n// Flow%d creates a function that takes an initial value t0 and successively applies %d functions where the input of a function is the return value of the previous function\n// The final return value is the result of the last function application\n", i, i)
+	fmt.Fprintf(f, "func Flow%d[", i)
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "F%d ~func(T%d) T%d", j, j-1, j)
+	}
+	for j := 0; j <= i; j++ {
+		fmt.Fprintf(f, ", T%d", j)
+	}
+	fmt.Fprintf(f, " any](")
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "f%d F%d", j, j)
+	}
+	fmt.Fprintf(f, ") func(T0) T%d {\n", i)
+	fmt.Fprintf(f, "  return func(t0 T0) T%d {\n", i)
+	fmt.Fprintf(f, "    return Pipe%d(t0", i)
+	for j := 1; j <= i; j++ {
+		fmt.Fprintf(f, ", f%d", j)
+	}
+	fmt.Fprintf(f, ")\n")
+	fmt.Fprintln(f, "  }")
+
+	fmt.Fprintln(f, "}")
+
+}
+
+func generatePipe(f *os.File, i int) {
+	// Create the pipe version
+	fmt.Fprintf(f, "\n// Pipe%d takes an initial value t0 and successively applies %d functions where the input of a function is the return value of the previous function\n// The final return value is the result of the last function application\n", i, i)
+	fmt.Fprintf(f, "func Pipe%d[", i)
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "F%d ~func(T%d) T%d", j, j-1, j)
+	}
+	if i > 0 {
+		fmt.Fprintf(f, ", ")
+	}
+	for j := 0; j <= i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j)
+	}
+
+	fmt.Fprintf(f, " any](t0 T0")
+	for j := 1; j <= i; j++ {
+		fmt.Fprintf(f, ", f%d F%d", j, j)
+	}
+	fmt.Fprintf(f, ") T%d {\n", i)
+	fmt.Fprintf(f, "  return ")
+	for j := i; j >= 1; j-- {
+		fmt.Fprintf(f, "f%d(", j)
+	}
+	fmt.Fprintf(f, "t0")
+	for j := 1; j <= i; j++ {
+		fmt.Fprintf(f, ")")
+	}
+	fmt.Fprintf(f, "\n")
+	fmt.Fprintln(f, "}")
+}
+
+func recurseCurry(f *os.File, indent string, total, count int) {
+	if count == 1 {
+		fmt.Fprintf(f, "%sreturn func(t%d T%d) T%d {\n", indent, total-1, total-1, total)
+		fmt.Fprintf(f, "%s  return f(t0", indent)
+		for i := 1; i < total; i++ {
+			fmt.Fprintf(f, ", t%d", i)
+		}
+		fmt.Fprintf(f, ")\n")
+		fmt.Fprintf(f, "%s}\n", indent)
+	} else {
+		fmt.Fprintf(f, "%sreturn", indent)
+		for i := total - count + 1; i <= total; i++ {
+			fmt.Fprintf(f, " func(t%d T%d)", i-1, i-1)
+		}
+		fmt.Fprintf(f, " T%d {\n", total)
+		recurseCurry(f, fmt.Sprintf("  %s", indent), total, count-1)
+		fmt.Fprintf(f, "%s}\n", indent)
+	}
+}
+
+func generateCurry(f *os.File, i int) {
+	// Create the curry version
+	fmt.Fprintf(f, "\n// Curry%d takes a function with %d parameters and returns a cascade of functions each taking only one parameter.\n// The inverse function is [Uncurry%d]\n", i, i, i)
+	fmt.Fprintf(f, "func Curry%d[FCT ~func(T0", i)
+	for j := 1; j < i; j++ {
+		fmt.Fprintf(f, ", T%d", j)
+	}
+	fmt.Fprintf(f, ") T%d", i)
+	// type arguments
+	for j := 0; j <= i; j++ {
+		fmt.Fprintf(f, ", T%d", j)
+	}
+	fmt.Fprintf(f, " any](f FCT) func(T0)")
+	for j := 2; j <= i; j++ {
+		fmt.Fprintf(f, " func(T%d)", j-1)
+	}
+	fmt.Fprintf(f, " T%d {\n", i)
+	recurseCurry(f, "  ", i, i)
+	fmt.Fprintf(f, "}\n")
+}
+
+func generateUncurry(f *os.File, i int) {
+	// Create the uncurry version
+	fmt.Fprintf(f, "\n// Uncurry%d takes a cascade of %d functions each taking only one parameter and returns a function with %d parameters .\n// The inverse function is [Curry%d]\n", i, i, i, i)
+	fmt.Fprintf(f, "func Uncurry%d[FCT ~func(T0)", i)
+	for j := 1; j < i; j++ {
+		fmt.Fprintf(f, " func(T%d)", j)
+	}
+	fmt.Fprintf(f, " T%d", i)
+	// the type parameters
+	for j := 0; j <= i; j++ {
+		fmt.Fprintf(f, ", T%d", j)
+	}
+	fmt.Fprintf(f, " any](f FCT) func(")
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j-1)
+	}
+	fmt.Fprintf(f, ") T%d {\n", i)
+	fmt.Fprintf(f, "  return func(")
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "t%d T%d", j-1, j-1)
+	}
+	fmt.Fprintf(f, ") T%d {\n", i)
+	fmt.Fprintf(f, "    return f")
+	for j := 1; j <= i; j++ {
+		fmt.Fprintf(f, "(t%d)", j-1)
+	}
+	fmt.Fprintln(f)
+
+	fmt.Fprintf(f, "  }\n")
+
+	fmt.Fprintf(f, "}\n")
+}
+
+func generatePipeHelpers(filename string, count int) error {
+	dir, err := os.Getwd()
+	if err != nil {
+		return err
+	}
+	absDir, err := filepath.Abs(dir)
+	if err != nil {
+		return err
+	}
+	pkg := filepath.Base(absDir)
+	f, err := os.Create(filepath.Clean(filename))
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	// log
+	log.Printf("Generating code in [%s] for package [%s] with [%d] repetitions ...", filename, pkg, count)
+
+	// some header
+	fmt.Fprintln(f, "// Code generated by go generate; DO NOT EDIT.")
+	fmt.Fprintln(f, "// This file was generated by robots at")
+	fmt.Fprintf(f, "// %s\n\n", time.Now())
+
+	fmt.Fprintf(f, "package %s\n", pkg)
+
+	// pipe
+	generatePipe(f, 0)
+	// variadic
+	generateVariadic(f, 0)
+	// unvariadic
+	generateUnvariadic(f, 0)
+	// unsliced
+	generateUnsliced(f, 0)
+
+	for i := 1; i <= count; i++ {
+
+		// pipe
+		generatePipe(f, i)
+		// flow
+		generateFlow(f, i)
+		// nullary
+		generateNullary(f, i)
+		// curry
+		generateCurry(f, i)
+		// uncurry
+		generateUncurry(f, i)
+		// variadic
+		generateVariadic(f, i)
+		// unvariadic
+		generateUnvariadic(f, i)
+		// unsliced
+		generateUnsliced(f, i)
+	}
+
+	return nil
+}
+
+func PipeCommand() *C.Command {
+	return &C.Command{
+		Name:        "pipe",
+		Usage:       "generate code for pipe, flow, curry, etc",
+		Description: "Code generation for pipe, flow, curry, etc",
+		Flags: []C.Flag{
+			flagCount,
+			flagFilename,
+		},
+		Action: func(ctx *C.Context) error {
+			return generatePipeHelpers(
+				ctx.String(keyFilename),
+				ctx.Int(keyCount),
+			)
+		},
+	}
+}

v2/cli/reader.go

@@ -0,0 +1,164 @@
+// 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 cli
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"time"
+
+	C "github.com/urfave/cli/v2"
+)
+
+func generateReaderFrom(f, fg *os.File, i int) {
+	// non generic version
+	fmt.Fprintf(f, "\n// From%d converts a function with %d parameters returning a [R] into a function with %d parameters returning a [Reader[C, R]]\n// The first parameter is considered to be the context [C] of the reader\n", i, i+1, i)
+	fmt.Fprintf(f, "func From%d[F ~func(C", i)
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, ", T%d", j)
+	}
+	fmt.Fprintf(f, ") R")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, ", T%d", j)
+	}
+	fmt.Fprintf(f, ", C, R any](f F) func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j)
+	}
+	fmt.Fprintf(f, ") Reader[C, R] {\n")
+	fmt.Fprintf(f, "  return G.From%d[Reader[C, R]](f)\n", i)
+	fmt.Fprintln(f, "}")
+
+	// generic version
+	fmt.Fprintf(fg, "\n// From%d converts a function with %d parameters returning a [R] into a function with %d parameters returning a [GRA]\n// The first parameter is considered to be the context [C].\n", i, i+1, i)
+	fmt.Fprintf(fg, "func From%d[GRA ~func(C) R, F ~func(C", i)
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(fg, ", T%d", j)
+	}
+	fmt.Fprintf(fg, ") R")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(fg, ", T%d", j)
+	}
+	fmt.Fprintf(fg, ", C, R any](f F) func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(fg, ", ")
+		}
+		fmt.Fprintf(fg, "T%d", j)
+	}
+	fmt.Fprintf(fg, ") GRA {\n")
+
+	fmt.Fprintf(fg, "  return func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(fg, ", ")
+		}
+		fmt.Fprintf(fg, "t%d T%d", j, j)
+	}
+	fmt.Fprintf(fg, ") GRA {\n")
+	fmt.Fprintf(fg, "    return MakeReader[GRA](func(r C) R {\n")
+	fmt.Fprintf(fg, "      return f(r")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(fg, ", t%d", j)
+	}
+	fmt.Fprintf(fg, ")\n")
+	fmt.Fprintf(fg, "    })\n")
+	fmt.Fprintf(fg, "  }\n")
+	fmt.Fprintf(fg, "}\n")
+}
+
+func generateReaderHelpers(filename string, count int) error {
+	dir, err := os.Getwd()
+	if err != nil {
+		return err
+	}
+	absDir, err := filepath.Abs(dir)
+	if err != nil {
+		return err
+	}
+	pkg := filepath.Base(absDir)
+	f, err := os.Create(filepath.Clean(filename))
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	// construct subdirectory
+	genFilename := filepath.Join("generic", filename)
+	err = os.MkdirAll("generic", os.ModePerm)
+	if err != nil {
+		return err
+	}
+	fg, err := os.Create(filepath.Clean(genFilename))
+	if err != nil {
+		return err
+	}
+	defer fg.Close()
+
+	// log
+	log.Printf("Generating code in [%s] for package [%s] with [%d] repetitions ...", filename, pkg, count)
+
+	// some header
+	fmt.Fprintln(f, "// Code generated by go generate; DO NOT EDIT.")
+	fmt.Fprintln(f, "// This file was generated by robots at")
+	fmt.Fprintf(f, "// %s\n\n", time.Now())
+
+	fmt.Fprintf(f, "package %s\n\n", pkg)
+
+	fmt.Fprintf(f, `
+import (
+	G "github.com/IBM/fp-go/v2/%s/generic"	
+)
+`, pkg)
+
+	// some header
+	fmt.Fprintln(fg, "// Code generated by go generate; DO NOT EDIT.")
+	fmt.Fprintln(fg, "// This file was generated by robots at")
+	fmt.Fprintf(fg, "// %s\n", time.Now())
+
+	fmt.Fprintf(fg, "package generic\n\n")
+
+	// from
+	generateReaderFrom(f, fg, 0)
+
+	for i := 1; i <= count; i++ {
+		// from
+		generateReaderFrom(f, fg, i)
+	}
+
+	return nil
+}
+
+func ReaderCommand() *C.Command {
+	return &C.Command{
+		Name:  "reader",
+		Usage: "generate code for Reader",
+		Flags: []C.Flag{
+			flagCount,
+			flagFilename,
+		},
+		Action: func(ctx *C.Context) error {
+			return generateReaderHelpers(
+				ctx.String(keyFilename),
+				ctx.Int(keyCount),
+			)
+		},
+	}
+}

v2/cli/readerioeither.go

@@ -0,0 +1,294 @@
+// 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 cli
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"time"
+
+	C "github.com/urfave/cli/v2"
+)
+
+func generateReaderIOEitherFrom(f, fg *os.File, i int) {
+	// non generic version
+	fmt.Fprintf(f, "\n// From%d converts a function with %d parameters returning a tuple into a function with %d parameters returning a [ReaderIOEither[R]]\n// The first parameter is considered to be the context [C].\n", i, i+1, i)
+	fmt.Fprintf(f, "func From%d[F ~func(C", i)
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, ", T%d", j)
+	}
+	fmt.Fprintf(f, ") func() (R, error)")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, ", T%d", j)
+	}
+	fmt.Fprintf(f, ", C, R any](f F) func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j)
+	}
+	fmt.Fprintf(f, ") ReaderIOEither[C, error, R] {\n")
+	fmt.Fprintf(f, "  return G.From%d[ReaderIOEither[C, error, R]](f)\n", i)
+	fmt.Fprintln(f, "}")
+
+	// generic version
+	fmt.Fprintf(fg, "\n// From%d converts a function with %d parameters returning a tuple into a function with %d parameters returning a [GRA]\n// The first parameter is considerd to be the context [C].\n", i, i+1, i)
+	fmt.Fprintf(fg, "func From%d[GRA ~func(C) GIOA, F ~func(C", i)
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(fg, ", T%d", j)
+	}
+	fmt.Fprintf(fg, ") func() (R, error), GIOA ~func() E.Either[error, R]")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(fg, ", T%d", j)
+	}
+	fmt.Fprintf(fg, ", C, R any](f F) func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(fg, ", ")
+		}
+		fmt.Fprintf(fg, "T%d", j)
+	}
+	fmt.Fprintf(fg, ") GRA {\n")
+
+	fmt.Fprintf(fg, "  return RD.From%d[GRA](func(r C", i)
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(fg, ", t%d T%d", j, j)
+	}
+	fmt.Fprintf(fg, ") GIOA {\n")
+	fmt.Fprintf(fg, "    return E.Eitherize0(f(r")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(fg, ", t%d", j)
+	}
+	fmt.Fprintf(fg, "))\n")
+	fmt.Fprintf(fg, "  })\n")
+	fmt.Fprintf(fg, "}\n")
+}
+
+func generateReaderIOEitherEitherize(f, fg *os.File, i int) {
+	// non generic version
+	fmt.Fprintf(f, "\n// Eitherize%d converts a function with %d parameters returning a tuple into a function with %d parameters returning a [ReaderIOEither[C, error, R]]\n// The first parameter is considered to be the context [C].\n", i, i+1, i)
+	fmt.Fprintf(f, "func Eitherize%d[F ~func(C", i)
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, ", T%d", j)
+	}
+	fmt.Fprintf(f, ") (R, error)")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, ", T%d", j)
+	}
+	fmt.Fprintf(f, ", C, R any](f F) func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j)
+	}
+	fmt.Fprintf(f, ") ReaderIOEither[C, error, R] {\n")
+	fmt.Fprintf(f, "  return G.Eitherize%d[ReaderIOEither[C, error, R]](f)\n", i)
+	fmt.Fprintln(f, "}")
+
+	// generic version
+	fmt.Fprintf(fg, "\n// Eitherize%d converts a function with %d parameters returning a tuple into a function with %d parameters returning a [GRA]\n// The first parameter is considered to be the context [C].\n", i, i, i)
+	fmt.Fprintf(fg, "func Eitherize%d[GRA ~func(C) GIOA, F ~func(C", i)
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(fg, ", T%d", j)
+	}
+	fmt.Fprintf(fg, ") (R, error), GIOA ~func() E.Either[error, R]")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(fg, ", T%d", j)
+	}
+	fmt.Fprintf(fg, ", C, R any](f F) func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(fg, ", ")
+		}
+		fmt.Fprintf(fg, "T%d", j)
+	}
+	fmt.Fprintf(fg, ") GRA {\n")
+
+	fmt.Fprintf(fg, "  return From%d[GRA](func(r C", i)
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(fg, ", t%d T%d", j, j)
+	}
+	fmt.Fprintf(fg, ") func() (R, error) {\n")
+	fmt.Fprintf(fg, "    return func() (R, error) {\n")
+	fmt.Fprintf(fg, "      return f(r")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(fg, ", t%d", j)
+	}
+	fmt.Fprintf(fg, ")\n")
+	fmt.Fprintf(fg, "    }})\n")
+	fmt.Fprintf(fg, "}\n")
+}
+
+func generateReaderIOEitherUneitherize(f, fg *os.File, i int) {
+	// non generic version
+	fmt.Fprintf(f, "\n// Uneitherize%d converts a function with %d parameters returning a [ReaderIOEither[C, error, R]] into a function with %d parameters returning a tuple.\n// The first parameter is considered to be the context [C].\n", i, i+1, i)
+	fmt.Fprintf(f, "func Uneitherize%d[F ~func(", i)
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j)
+	}
+	fmt.Fprintf(f, ") ReaderIOEither[C, error, R]")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, ", T%d", j)
+	}
+	fmt.Fprintf(f, ", C, R any](f F) func(C")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, ", T%d", j)
+	}
+	fmt.Fprintf(f, ") (R, error) {\n")
+	fmt.Fprintf(f, "  return G.Uneitherize%d[ReaderIOEither[C, error, R]", i)
+
+	fmt.Fprintf(f, ", func(C")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, ", T%d", j)
+	}
+	fmt.Fprintf(f, ")(R, error)](f)\n")
+	fmt.Fprintln(f, "}")
+
+	// generic version
+	fmt.Fprintf(fg, "\n// Uneitherize%d converts a function with %d parameters returning a [GRA] into a function with %d parameters returning a tuple.\n// The first parameter is considered to be the context [C].\n", i, i, i)
+	fmt.Fprintf(fg, "func Uneitherize%d[GRA ~func(C) GIOA, F ~func(C", i)
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(fg, ", T%d", j)
+	}
+	fmt.Fprintf(fg, ") (R, error), GIOA ~func() E.Either[error, R]")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(fg, ", T%d", j)
+	}
+	fmt.Fprintf(fg, ", C, R any](f func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(fg, ", ")
+		}
+		fmt.Fprintf(fg, "T%d", j)
+	}
+	fmt.Fprintf(fg, ") GRA) F {\n")
+
+	fmt.Fprintf(fg, "  return func(c C")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(fg, ", t%d T%d", j, j)
+	}
+	fmt.Fprintf(fg, ") (R, error) {\n")
+	fmt.Fprintf(fg, "    return E.UnwrapError(f(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(fg, ", ")
+		}
+		fmt.Fprintf(fg, "t%d", j)
+	}
+	fmt.Fprintf(fg, ")(c)())\n")
+	fmt.Fprintf(fg, "  }\n")
+	fmt.Fprintf(fg, "}\n")
+}
+
+func generateReaderIOEitherHelpers(filename string, count int) error {
+	dir, err := os.Getwd()
+	if err != nil {
+		return err
+	}
+	absDir, err := filepath.Abs(dir)
+	if err != nil {
+		return err
+	}
+	pkg := filepath.Base(absDir)
+	f, err := os.Create(filepath.Clean(filename))
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	// construct subdirectory
+	genFilename := filepath.Join("generic", filename)
+	err = os.MkdirAll("generic", os.ModePerm)
+	if err != nil {
+		return err
+	}
+	fg, err := os.Create(filepath.Clean(genFilename))
+	if err != nil {
+		return err
+	}
+	defer fg.Close()
+
+	// log
+	log.Printf("Generating code in [%s] for package [%s] with [%d] repetitions ...", filename, pkg, count)
+
+	// some header
+	fmt.Fprintln(f, "// Code generated by go generate; DO NOT EDIT.")
+	fmt.Fprintln(f, "// This file was generated by robots at")
+	fmt.Fprintf(f, "// %s\n\n", time.Now())
+
+	fmt.Fprintf(f, "package %s\n\n", pkg)
+
+	fmt.Fprintf(f, `
+import (
+	G "github.com/IBM/fp-go/v2/%s/generic"	
+)
+`, pkg)
+
+	// some header
+	fmt.Fprintln(fg, "// Code generated by go generate; DO NOT EDIT.")
+	fmt.Fprintln(fg, "// This file was generated by robots at")
+	fmt.Fprintf(fg, "// %s\n", time.Now())
+
+	fmt.Fprintf(fg, "package generic\n\n")
+
+	fmt.Fprintf(fg, `
+import (
+	E "github.com/IBM/fp-go/v2/either"
+	RD "github.com/IBM/fp-go/v2/reader/generic"
+)
+`)
+
+	// from
+	generateReaderIOEitherFrom(f, fg, 0)
+	// eitherize
+	generateReaderIOEitherEitherize(f, fg, 0)
+	// uneitherize
+	generateReaderIOEitherUneitherize(f, fg, 0)
+
+	for i := 1; i <= count; i++ {
+		// from
+		generateReaderIOEitherFrom(f, fg, i)
+		// eitherize
+		generateReaderIOEitherEitherize(f, fg, i)
+		// uneitherize
+		generateReaderIOEitherUneitherize(f, fg, i)
+	}
+
+	return nil
+}
+
+func ReaderIOEitherCommand() *C.Command {
+	return &C.Command{
+		Name:  "readerioeither",
+		Usage: "generate code for ReaderIOEither",
+		Flags: []C.Flag{
+			flagCount,
+			flagFilename,
+		},
+		Action: func(ctx *C.Context) error {
+			return generateReaderIOEitherHelpers(
+				ctx.String(keyFilename),
+				ctx.Int(keyCount),
+			)
+		},
+	}
+}

v2/cli/templates/functions.go

@@ -0,0 +1,15 @@
+package templates
+
+import (
+	"text/template"
+
+	E "github.com/IBM/fp-go/v2/either"
+)
+
+var (
+	templateFunctions = template.FuncMap{}
+)
+
+func Parse(name, tmpl string) E.Either[error, *template.Template] {
+	return E.TryCatchError(template.New(name).Funcs(templateFunctions).Parse(tmpl))
+}

v2/cli/tuple.go

@@ -0,0 +1,625 @@
+// 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 cli
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+
+	C "github.com/urfave/cli/v2"
+)
+
+func writeTupleType(f *os.File, symbol string, i int) {
+	fmt.Fprintf(f, "Tuple%d[", i)
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "%s%d", symbol, j)
+	}
+	fmt.Fprintf(f, "]")
+}
+
+func makeTupleType(name string) func(i int) string {
+	return func(i int) string {
+		var buf strings.Builder
+		buf.WriteString(fmt.Sprintf("Tuple%d[", i))
+		for j := 0; j < i; j++ {
+			if j > 0 {
+				buf.WriteString(", ")
+			}
+			buf.WriteString(fmt.Sprintf("%s%d", name, j+1))
+		}
+		buf.WriteString("]")
+
+		return buf.String()
+	}
+}
+
+func generatePush(f *os.File, i int) {
+	tuple1 := makeTupleType("T")(i)
+	tuple2 := makeTupleType("T")(i + 1)
+	// Create the replicate version
+	fmt.Fprintf(f, "\n// Push%d creates a [Tuple%d] from a [Tuple%d] by appending a constant value\n", i, i+1, i)
+	fmt.Fprintf(f, "func Push%d[", i)
+	// function prototypes
+	for j := 0; j <= i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j+1)
+	}
+	fmt.Fprintf(f, " any](value T%d) func(%s) %s {\n", i+1, tuple1, tuple2)
+	fmt.Fprintf(f, "  return func(t %s) %s {\n", tuple1, tuple2)
+	fmt.Fprintf(f, "    return MakeTuple%d(", i+1)
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "t.F%d", j+1)
+	}
+	fmt.Fprintf(f, ", value)\n")
+	fmt.Fprintf(f, "  }\n")
+	fmt.Fprintf(f, "}\n")
+}
+
+func generateReplicate(f *os.File, i int) {
+	// Create the replicate version
+	fmt.Fprintf(f, "\n// Replicate%d creates a [Tuple%d] with all fields set to the input value `t`\n", i, i)
+	fmt.Fprintf(f, "func Replicate%d[T any](t T) Tuple%d[", i, i)
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T")
+	}
+	fmt.Fprintf(f, "] {\n")
+	// execute the mapping
+	fmt.Fprintf(f, "  return MakeTuple%d(", i)
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "t")
+	}
+	fmt.Fprintf(f, ")\n")
+	fmt.Fprintf(f, "}\n")
+}
+
+func generateMap(f *os.File, i int) {
+	// Create the optionize version
+	fmt.Fprintf(f, "\n// Map%d maps each value of a [Tuple%d] via a mapping function\n", i, i)
+	fmt.Fprintf(f, "func Map%d[", i)
+	// function prototypes
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "F%d ~func(T%d) R%d", j, j, j)
+	}
+	for j := 1; j <= i; j++ {
+		fmt.Fprintf(f, ", T%d, R%d", j, j)
+	}
+	fmt.Fprintf(f, " any](")
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "f%d F%d", j, j)
+	}
+	fmt.Fprintf(f, ") func(")
+	writeTupleType(f, "T", i)
+	fmt.Fprintf(f, ") ")
+	writeTupleType(f, "R", i)
+	fmt.Fprintf(f, " {\n")
+
+	fmt.Fprintf(f, " return func(t ")
+	writeTupleType(f, "T", i)
+	fmt.Fprintf(f, ") ")
+	writeTupleType(f, "R", i)
+	fmt.Fprintf(f, " {\n")
+
+	// execute the mapping
+	fmt.Fprintf(f, "    return MakeTuple%d(\n", i)
+	for j := 1; j <= i; j++ {
+		fmt.Fprintf(f, "      f%d(t.F%d),\n", j, j)
+	}
+	fmt.Fprintf(f, "    )\n")
+
+	fmt.Fprintf(f, " }\n")
+	fmt.Fprintf(f, "}\n")
+}
+
+func generateMonoid(f *os.File, i int) {
+	// Create the optionize version
+	fmt.Fprintf(f, "\n// Monoid%d creates a [Monoid] for a [Tuple%d] based on %d monoids for the contained types\n", i, i, i)
+	fmt.Fprintf(f, "func Monoid%d[", i)
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j)
+	}
+	fmt.Fprintf(f, " any](")
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "m%d M.Monoid[T%d]", j, j)
+	}
+	fmt.Fprintf(f, ") M.Monoid[")
+	writeTupleType(f, "T", i)
+	fmt.Fprintf(f, "] {\n")
+
+	fmt.Fprintf(f, "  return M.MakeMonoid(func(l, r ")
+	writeTupleType(f, "T", i)
+	fmt.Fprintf(f, ") ")
+	writeTupleType(f, "T", i)
+	fmt.Fprintf(f, "{\n")
+
+	fmt.Fprintf(f, "    return MakeTuple%d(", i)
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "m%d.Concat(l.F%d, r.F%d)", j, j, j)
+	}
+	fmt.Fprintf(f, ")\n")
+	fmt.Fprintf(f, "  }, MakeTuple%d(", i)
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "m%d.Empty()", j)
+	}
+	fmt.Fprintf(f, "))\n")
+
+	fmt.Fprintf(f, "}\n")
+}
+
+func generateOrd(f *os.File, i int) {
+	// Create the optionize version
+	fmt.Fprintf(f, "\n// Ord%d creates n [Ord] for a [Tuple%d] based on %d [Ord]s for the contained types\n", i, i, i)
+	fmt.Fprintf(f, "func Ord%d[", i)
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j)
+	}
+	fmt.Fprintf(f, " any](")
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "o%d O.Ord[T%d]", j, j)
+	}
+	fmt.Fprintf(f, ") O.Ord[")
+	writeTupleType(f, "T", i)
+	fmt.Fprintf(f, "] {\n")
+
+	fmt.Fprintf(f, "  return O.MakeOrd(func(l, r ")
+	writeTupleType(f, "T", i)
+	fmt.Fprintf(f, ") int {\n")
+
+	for j := 1; j <= i; j++ {
+		fmt.Fprintf(f, "    if c:= o%d.Compare(l.F%d, r.F%d); c != 0 {return c}\n", j, j, j)
+	}
+	fmt.Fprintf(f, "    return 0\n")
+	fmt.Fprintf(f, "  }, func(l, r ")
+	writeTupleType(f, "T", i)
+	fmt.Fprintf(f, ") bool {\n")
+	fmt.Fprintf(f, "    return ")
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, " && ")
+		}
+		fmt.Fprintf(f, "o%d.Equals(l.F%d, r.F%d)", j, j, j)
+	}
+	fmt.Fprintf(f, "\n")
+	fmt.Fprintf(f, "  })\n")
+
+	fmt.Fprintf(f, "}\n")
+}
+
+func generateTupleType(f *os.File, i int) {
+	// Create the optionize version
+	fmt.Fprintf(f, "\n// Tuple%d is a struct that carries %d independently typed values\n", i, i)
+	fmt.Fprintf(f, "type Tuple%d[", i)
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j)
+	}
+	fmt.Fprintf(f, " any] struct {\n")
+	for j := 1; j <= i; j++ {
+		fmt.Fprintf(f, "  F%d T%d\n", j, j)
+	}
+	fmt.Fprintf(f, "}\n")
+}
+
+func generateMakeTupleType(f *os.File, i int) {
+	// Create the optionize version
+	fmt.Fprintf(f, "\n// MakeTuple%d is a function that converts its %d parameters into a [Tuple%d]\n", i, i, i)
+	fmt.Fprintf(f, "func MakeTuple%d[", i)
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j)
+	}
+	fmt.Fprintf(f, " any](")
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "t%d T%d", j, j)
+	}
+	fmt.Fprintf(f, ") ")
+	writeTupleType(f, "T", i)
+	fmt.Fprintf(f, " {\n")
+	fmt.Fprintf(f, "  return Tuple%d[", i)
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j)
+	}
+	fmt.Fprintf(f, "]{")
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "t%d", j)
+	}
+	fmt.Fprintf(f, "}\n")
+	fmt.Fprintf(f, "}\n")
+}
+
+func generateUntupled(f *os.File, i int) {
+	// Create the optionize version
+	fmt.Fprintf(f, "\n// Untupled%d converts a function with a [Tuple%d] parameter into a function with %d parameters\n// The inverse function is [Tupled%d]\n", i, i, i, i)
+	fmt.Fprintf(f, "func Untupled%d[F ~func(Tuple%d[", i, i)
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j+1)
+	}
+	fmt.Fprintf(f, "]) R")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, ", T%d", j+1)
+	}
+	fmt.Fprintf(f, ", R any](f F) func(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j+1)
+	}
+	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 T%d", j+1, j+1)
+	}
+	fmt.Fprintf(f, ") R {\n")
+	fmt.Fprintf(f, "    return f(MakeTuple%d(", i)
+	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 generateTupled(f *os.File, i int) {
+	// Create the optionize version
+	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 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j+1)
+	}
+	fmt.Fprintf(f, ") R")
+	for j := 0; j < i; j++ {
+		fmt.Fprintf(f, ", T%d", j+1)
+	}
+	fmt.Fprintf(f, ", R any](f F) func(Tuple%d[", i)
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j+1)
+	}
+	fmt.Fprintf(f, "]) R {\n")
+	fmt.Fprintf(f, "  return func(t Tuple%d[", i)
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "T%d", j+1)
+	}
+	fmt.Fprintf(f, "]) R {\n")
+	fmt.Fprintf(f, "    return f(")
+	for j := 0; j < i; j++ {
+		if j > 0 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "t.F%d", j+1)
+	}
+	fmt.Fprintf(f, ")\n")
+	fmt.Fprintf(f, "  }\n")
+	fmt.Fprintln(f, "}")
+}
+
+func generateTupleHelpers(filename string, count int) error {
+	dir, err := os.Getwd()
+	if err != nil {
+		return err
+	}
+	absDir, err := filepath.Abs(dir)
+	if err != nil {
+		return err
+	}
+	pkg := filepath.Base(absDir)
+	f, err := os.Create(filepath.Clean(filename))
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	// log
+	log.Printf("Generating code in [%s] for package [%s] with [%d] repetitions ...", filename, pkg, count)
+
+	// some header
+	fmt.Fprintln(f, "// Code generated by go generate; DO NOT EDIT.")
+	fmt.Fprintln(f, "// This file was generated by robots at")
+	fmt.Fprintf(f, "// %s\n\n", time.Now())
+
+	fmt.Fprintf(f, "package %s\n\n", pkg)
+
+	fmt.Fprintf(f, `
+import (
+	M "github.com/IBM/fp-go/v2/monoid"
+	O "github.com/IBM/fp-go/v2/ord"	
+)
+`)
+
+	for i := 1; i <= count; i++ {
+		// tuple type
+		generateTupleType(f, i)
+	}
+
+	for i := 1; i <= count; i++ {
+		// tuple generator
+		generateMakeTupleType(f, i)
+		// tupled wrapper
+		generateTupled(f, i)
+		// untupled wrapper
+		generateUntupled(f, i)
+		// monoid
+		generateMonoid(f, i)
+		// generate order
+		generateOrd(f, i)
+		// generate map
+		generateMap(f, i)
+		// generate replicate
+		generateReplicate(f, i)
+		// generate tuple functions such as string and fmt
+		generateTupleString(f, i)
+		// generate json support
+		generateTupleMarshal(f, i)
+		// generate json support
+		generateTupleUnmarshal(f, i)
+		// generate toArray
+		generateToArray(f, i)
+		// generate fromArray
+		generateFromArray(f, i)
+		// generate push
+		if i < count {
+			generatePush(f, i)
+		}
+	}
+
+	return nil
+}
+
+func generateTupleMarshal(f *os.File, i int) {
+	// Create the stringify version
+	fmt.Fprintf(f, "\n// MarshalJSON marshals the [Tuple%d] into a JSON array\n", i)
+	fmt.Fprintf(f, "func (t ")
+	writeTupleType(f, "T", i)
+	fmt.Fprintf(f, ") MarshalJSON() ([]byte, error) {\n")
+	fmt.Fprintf(f, "  return tupleMarshalJSON(")
+	// function prototypes
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "t.F%d", j)
+	}
+	fmt.Fprintf(f, ")\n")
+	fmt.Fprintf(f, "}\n")
+}
+
+func generateTupleUnmarshal(f *os.File, i int) {
+	// Create the stringify version
+	fmt.Fprintf(f, "\n// UnmarshalJSON unmarshals a JSON array into a [Tuple%d]\n", i)
+	fmt.Fprintf(f, "func (t *")
+	writeTupleType(f, "T", i)
+	fmt.Fprintf(f, ") UnmarshalJSON(data []byte) error {\n")
+	fmt.Fprintf(f, "  return tupleUnmarshalJSON(data")
+	// function prototypes
+	for j := 1; j <= i; j++ {
+		fmt.Fprintf(f, ", &t.F%d", j)
+	}
+	fmt.Fprintf(f, ")\n")
+	fmt.Fprintf(f, "}\n")
+}
+
+func generateToArray(f *os.File, i int) {
+	// Create the stringify version
+	fmt.Fprintf(f, "\n// ToArray converts the [Tuple%d] into an array of type [R] using %d transformation functions from [T] to [R]\n// The inverse function is [FromArray%d]\n", i, i, i)
+	fmt.Fprintf(f, "func ToArray%d[", i)
+	// function prototypes
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "F%d ~func(T%d) R", j, j)
+	}
+	for j := 1; j <= i; j++ {
+		fmt.Fprintf(f, ", T%d", j)
+	}
+	fmt.Fprintf(f, ", R any](")
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "f%d F%d", j, j)
+	}
+	fmt.Fprintf(f, ") func(t ")
+	writeTupleType(f, "T", i)
+	fmt.Fprintf(f, ") []R {\n")
+	fmt.Fprintf(f, "  return func(t ")
+	writeTupleType(f, "T", i)
+	fmt.Fprintf(f, ") []R {\n")
+	fmt.Fprintf(f, "    return []R{\n")
+	for j := 1; j <= i; j++ {
+		fmt.Fprintf(f, "      f%d(t.F%d),\n", j, j)
+	}
+	fmt.Fprintf(f, "    }\n")
+	fmt.Fprintf(f, "  }\n")
+	fmt.Fprintf(f, "}\n")
+}
+
+func generateFromArray(f *os.File, i int) {
+	// Create the stringify version
+	fmt.Fprintf(f, "\n// FromArray converts an array of [R] into a [Tuple%d] using %d functions from [R] to [T]\n// The inverse function is [ToArray%d]\n", i, i, i)
+	fmt.Fprintf(f, "func FromArray%d[", i)
+	// function prototypes
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "F%d ~func(R) T%d", j, j)
+	}
+	for j := 1; j <= i; j++ {
+		fmt.Fprintf(f, ", T%d", j)
+	}
+	fmt.Fprintf(f, ", R any](")
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "f%d F%d", j, j)
+	}
+	fmt.Fprintf(f, ") func(r []R) ")
+	writeTupleType(f, "T", i)
+	fmt.Fprintf(f, " {\n")
+	fmt.Fprintf(f, "  return func(r []R) ")
+	writeTupleType(f, "T", i)
+	fmt.Fprintf(f, " {\n")
+	fmt.Fprintf(f, "    return MakeTuple%d(\n", i)
+	for j := 1; j <= i; j++ {
+		fmt.Fprintf(f, "      f%d(r[%d]),\n", j, j-1)
+	}
+	fmt.Fprintf(f, "    )\n")
+	fmt.Fprintf(f, "  }\n")
+	fmt.Fprintf(f, "}\n")
+}
+
+func generateTupleString(f *os.File, i int) {
+	// Create the stringify version
+	fmt.Fprintf(f, "\n// String prints some debug info for the [Tuple%d]\n", i)
+	fmt.Fprintf(f, "func (t ")
+	writeTupleType(f, "T", i)
+	fmt.Fprintf(f, ") String() string {\n")
+	// convert to string
+	fmt.Fprint(f, "  return tupleString(")
+	for j := 1; j <= i; j++ {
+		if j > 1 {
+			fmt.Fprintf(f, ", ")
+		}
+		fmt.Fprintf(f, "t.F%d", j)
+	}
+	fmt.Fprintf(f, ")\n")
+	fmt.Fprintf(f, "}\n")
+}
+
+// func generateTupleJson(f *os.File, i int) {
+// 	// Create the stringify version
+// 	fmt.Fprintf(f, "\n// MarshalJSON converts the [Tuple%d] into a JSON byte stream\n", i)
+// 	fmt.Fprintf(f, "func (t ")
+// 	writeTupleType(f, "T", i)
+// 	fmt.Fprintf(f, ") MarshalJSON() ([]byte, error) {\n")
+// 	// convert to string
+// 	fmt.Fprintf(f, "  return fmt.Sprintf(\"Tuple%d[", i)
+// 	for j := 1; j <= i; j++ {
+// 		if j > 1 {
+// 			fmt.Fprintf(f, ", ")
+// 		}
+// 		fmt.Fprintf(f, "%s", "%T")
+// 	}
+// 	fmt.Fprintf(f, "](")
+// 	for j := 1; j <= i; j++ {
+// 		if j > 1 {
+// 			fmt.Fprintf(f, ", ")
+// 		}
+// 		fmt.Fprintf(f, "%s", "%v")
+// 	}
+// 	fmt.Fprintf(f, ")\", ")
+// 	for j := 1; j <= i; j++ {
+// 		if j > 1 {
+// 			fmt.Fprintf(f, ", ")
+// 		}
+// 		fmt.Fprintf(f, "t.F%d", j)
+// 	}
+// 	for j := 1; j <= i; j++ {
+// 		fmt.Fprintf(f, ", t.F%d", j)
+// 	}
+// 	fmt.Fprintf(f, ")\n")
+// 	fmt.Fprintf(f, "}\n")
+// }
+
+func TupleCommand() *C.Command {
+	return &C.Command{
+		Name:  "tuple",
+		Usage: "generate code for Tuple",
+		Flags: []C.Flag{
+			flagCount,
+			flagFilename,
+		},
+		Action: func(ctx *C.Context) error {
+			return generateTupleHelpers(
+				ctx.String(keyFilename),
+				ctx.Int(keyCount),
+			)
+		},
+	}
+}

v2/constant/const.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 constant
+
+import (
+	F "github.com/IBM/fp-go/v2/function"
+	M "github.com/IBM/fp-go/v2/monoid"
+	S "github.com/IBM/fp-go/v2/semigroup"
+)
+
+type Const[E, A any] struct {
+	value E
+}
+
+func Make[E, A any](e E) Const[E, A] {
+	return Const[E, A]{value: e}
+}
+
+func Unwrap[E, A any](c Const[E, A]) E {
+	return c.value
+}
+
+func Of[E, A any](m M.Monoid[E]) func(A) Const[E, A] {
+	return F.Constant1[A](Make[E, A](m.Empty()))
+}
+
+func MonadMap[E, A, B any](fa Const[E, A], _ func(A) B) Const[E, B] {
+	return Make[E, B](fa.value)
+}
+
+func MonadAp[E, A, B any](s S.Semigroup[E]) func(fab Const[E, func(A) B], fa Const[E, A]) Const[E, B] {
+	return func(fab Const[E, func(A) B], fa Const[E, A]) Const[E, B] {
+		return Make[E, B](s.Concat(fab.value, fa.value))
+	}
+}
+
+func Map[E, A, B any](f func(A) B) func(fa Const[E, A]) Const[E, B] {
+	return F.Bind2nd(MonadMap[E, A, B], f)
+}
+
+func Ap[E, A, B any](s S.Semigroup[E]) func(fa Const[E, A]) func(fab Const[E, func(A) B]) Const[E, B] {
+	monadap := MonadAp[E, A, B](s)
+	return func(fa Const[E, A]) func(fab Const[E, func(A) B]) Const[E, B] {
+		return F.Bind2nd(monadap, fa)
+	}
+}

v2/constant/const_test.go

@@ -0,0 +1,40 @@
+// Copyright (c) 2023 IBM Corp.
+// All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package constant
+
+import (
+	"testing"
+
+	F "github.com/IBM/fp-go/v2/function"
+	"github.com/IBM/fp-go/v2/internal/utils"
+	S "github.com/IBM/fp-go/v2/string"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestMap(t *testing.T) {
+	fa := Make[string, int]("foo")
+	assert.Equal(t, fa, F.Pipe1(fa, Map[string, int](utils.Double)))
+}
+
+func TestOf(t *testing.T) {
+	assert.Equal(t, Make[string, int](""), Of[string, int](S.Monoid)(1))
+}
+
+func TestAp(t *testing.T) {
+	fab := Make[string, int]("bar")
+	assert.Equal(t, Make[string, int]("foobar"), Ap[string, int, int](S.Monoid)(fab)(Make[string, func(int) int]("foo")))
+}

v2/constraints/constraints.go

@@ -0,0 +1,40 @@
+// Copyright (c) 2023 IBM Corp.
+// All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package constraints
+
+type Ordered interface {
+	Integer | Float | ~string
+}
+
+type Signed interface {
+	~int | ~int8 | ~int16 | ~int32 | ~int64
+}
+
+type Unsigned interface {
+	~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr
+}
+
+type Integer interface {
+	Signed | Unsigned
+}
+
+type Float interface {
+	~float32 | ~float64
+}
+
+type Complex interface {
+	~complex64 | ~complex128
+}

v2/context/doc.go

@@ -0,0 +1,17 @@
+// 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 context contains versions of reader IO monads that work with a golang [context.Context]
+package context

v2/context/ioeither/generic/ioeither.go

@@ -0,0 +1,33 @@
+// 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"
+
+	E "github.com/IBM/fp-go/v2/either"
+	IOE "github.com/IBM/fp-go/v2/ioeither/generic"
+)
+
+// WithContext wraps an existing IOEither and performs a context check for cancellation before delegating
+func WithContext[GIO ~func() E.Either[error, A], A any](ctx context.Context, ma GIO) GIO {
+	return IOE.MakeIO[GIO](func() E.Either[error, A] {
+		if err := context.Cause(ctx); err != nil {
+			return E.Left[A](err)
+		}
+		return ma()
+	})
+}

v2/context/ioeither/ioeither.go

@@ -0,0 +1,33 @@
+// 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 (
+	"context"
+
+	"github.com/IBM/fp-go/v2/either"
+	IOE "github.com/IBM/fp-go/v2/ioeither"
+)
+
+// withContext wraps an existing IOEither and performs a context check for cancellation before delegating
+func WithContext[A any](ctx context.Context, ma IOE.IOEither[error, A]) IOE.IOEither[error, A] {
+	return func() either.Either[error, A] {
+		if err := context.Cause(ctx); err != nil {
+			return either.Left[A](err)
+		}
+		return ma()
+	}
+}

v2/context/readereither/array.go

@@ -0,0 +1,33 @@
+// 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 readereither
+
+import "github.com/IBM/fp-go/v2/readereither"
+
+// TraverseArray transforms an array
+func TraverseArray[A, B any](f func(A) ReaderEither[B]) func([]A) ReaderEither[[]B] {
+	return readereither.TraverseArray(f)
+}
+
+// TraverseArrayWithIndex transforms an array
+func TraverseArrayWithIndex[A, B any](f func(int, A) ReaderEither[B]) func([]A) ReaderEither[[]B] {
+	return readereither.TraverseArrayWithIndex(f)
+}
+
+// SequenceArray converts a homogeneous sequence of either into an either of sequence
+func SequenceArray[A any](ma []ReaderEither[A]) ReaderEither[[]A] {
+	return readereither.SequenceArray(ma)
+}

v2/context/readereither/bind.go

@@ -0,0 +1,68 @@
+// 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 readereither
+
+import (
+	"context"
+
+	G "github.com/IBM/fp-go/v2/readereither/generic"
+)
+
+// Bind creates an empty context of type [S] to be used with the [Bind] operation
+func Do[S any](
+	empty S,
+) ReaderEither[S] {
+	return G.Do[ReaderEither[S], context.Context, error, S](empty)
+}
+
+// Bind attaches the result of a computation to a context [S1] to produce a context [S2]
+func Bind[S1, S2, T any](
+	setter func(T) func(S1) S2,
+	f func(S1) ReaderEither[T],
+) func(ReaderEither[S1]) ReaderEither[S2] {
+	return G.Bind[ReaderEither[S1], ReaderEither[S2], ReaderEither[T], context.Context, error, S1, S2, T](setter, f)
+}
+
+// Let attaches the result of a computation to a context [S1] to produce a context [S2]
+func Let[S1, S2, T any](
+	setter func(T) func(S1) S2,
+	f func(S1) T,
+) func(ReaderEither[S1]) ReaderEither[S2] {
+	return G.Let[ReaderEither[S1], ReaderEither[S2], context.Context, error, S1, S2, T](setter, f)
+}
+
+// LetTo attaches the a value to a context [S1] to produce a context [S2]
+func LetTo[S1, S2, T any](
+	setter func(T) func(S1) S2,
+	b T,
+) func(ReaderEither[S1]) ReaderEither[S2] {
+	return G.LetTo[ReaderEither[S1], ReaderEither[S2], context.Context, error, S1, S2, T](setter, b)
+}
+
+// BindTo initializes a new state [S1] from a value [T]
+func BindTo[S1, T any](
+	setter func(T) S1,
+) func(ReaderEither[T]) ReaderEither[S1] {
+	return G.BindTo[ReaderEither[S1], ReaderEither[T], context.Context, error, S1, T](setter)
+}
+
+// ApS attaches a value to a context [S1] to produce a context [S2] by considering the context and the value concurrently
+func ApS[S1, S2, T any](
+	setter func(T) func(S1) S2,
+	fa ReaderEither[T],
+) func(ReaderEither[S1]) ReaderEither[S2] {
+	return G.ApS[ReaderEither[S1], ReaderEither[S2], ReaderEither[T], context.Context, error, S1, S2, T](setter, fa)
+}

v2/context/readereither/bind_test.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 readereither
+
+import (
+	"context"
+	"testing"
+
+	E "github.com/IBM/fp-go/v2/either"
+	F "github.com/IBM/fp-go/v2/function"
+	"github.com/IBM/fp-go/v2/internal/utils"
+	"github.com/stretchr/testify/assert"
+)
+
+func getLastName(s utils.Initial) ReaderEither[string] {
+	return Of("Doe")
+}
+
+func getGivenName(s utils.WithLastName) ReaderEither[string] {
+	return Of("John")
+}
+
+func TestBind(t *testing.T) {
+
+	res := F.Pipe3(
+		Do(utils.Empty),
+		Bind(utils.SetLastName, getLastName),
+		Bind(utils.SetGivenName, getGivenName),
+		Map(utils.GetFullName),
+	)
+
+	assert.Equal(t, res(context.Background()), E.Of[error]("John Doe"))
+}
+
+func TestApS(t *testing.T) {
+
+	res := F.Pipe3(
+		Do(utils.Empty),
+		ApS(utils.SetLastName, Of("Doe")),
+		ApS(utils.SetGivenName, Of("John")),
+		Map(utils.GetFullName),
+	)
+
+	assert.Equal(t, res(context.Background()), E.Of[error]("John Doe"))
+}

v2/context/readereither/cancel.go

@@ -0,0 +1,32 @@
+// 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 readereither
+
+import (
+	"context"
+
+	E "github.com/IBM/fp-go/v2/either"
+)
+
+// withContext wraps an existing ReaderEither and performs a context check for cancellation before deletating
+func WithContext[A any](ma ReaderEither[A]) ReaderEither[A] {
+	return func(ctx context.Context) E.Either[error, A] {
+		if err := context.Cause(ctx); err != nil {
+			return E.Left[A](err)
+		}
+		return ma(ctx)
+	}
+}

v2/context/readereither/curry.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 readereither
+
+import (
+	"context"
+
+	"github.com/IBM/fp-go/v2/readereither"
+)
+
+// these functions curry a golang function with the context as the firsr parameter into a either reader with the context as the last parameter
+// this goes back to the advice in https://pkg.go.dev/context to put the context as a first parameter as a convention
+
+func Curry0[A any](f func(context.Context) (A, error)) ReaderEither[A] {
+	return readereither.Curry0(f)
+}
+
+func Curry1[T1, A any](f func(context.Context, T1) (A, error)) func(T1) ReaderEither[A] {
+	return readereither.Curry1(f)
+}
+
+func Curry2[T1, T2, A any](f func(context.Context, T1, T2) (A, error)) func(T1) func(T2) ReaderEither[A] {
+	return readereither.Curry2(f)
+}
+
+func Curry3[T1, T2, T3, A any](f func(context.Context, T1, T2, T3) (A, error)) func(T1) func(T2) func(T3) ReaderEither[A] {
+	return readereither.Curry3(f)
+}
+
+func Uncurry1[T1, A any](f func(T1) ReaderEither[A]) func(context.Context, T1) (A, error) {
+	return readereither.Uncurry1(f)
+}
+
+func Uncurry2[T1, T2, A any](f func(T1) func(T2) ReaderEither[A]) func(context.Context, T1, T2) (A, error) {
+	return readereither.Uncurry2(f)
+}
+
+func Uncurry3[T1, T2, T3, A any](f func(T1) func(T2) func(T3) ReaderEither[A]) func(context.Context, T1, T2, T3) (A, error) {
+	return readereither.Uncurry3(f)
+}

v2/context/readereither/exec/exec.go

@@ -0,0 +1,39 @@
+// 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 exec
+
+import (
+	"context"
+
+	"github.com/IBM/fp-go/v2/context/readereither"
+	"github.com/IBM/fp-go/v2/either"
+	"github.com/IBM/fp-go/v2/exec"
+	"github.com/IBM/fp-go/v2/function"
+	INTE "github.com/IBM/fp-go/v2/internal/exec"
+)
+
+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 ReaderIOEither version of the command
+	Command = function.Curry3(command)
+)
+
+func command(name string, args []string, in []byte) readereither.ReaderEither[exec.CommandOutput] {
+	return func(ctx context.Context) either.Either[error, exec.CommandOutput] {
+		return either.TryCatchError(INTE.Exec(ctx, name, args, in))
+	}
+}

v2/context/readereither/from.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 readereither
+
+import (
+	"context"
+
+	"github.com/IBM/fp-go/v2/readereither"
+)
+
+// these functions curry a golang function with the context as the firsr parameter into a either reader with the context as the last parameter
+// this goes back to the advice in https://pkg.go.dev/context to put the context as a first parameter as a convention
+
+func From0[A any](f func(context.Context) (A, error)) func() ReaderEither[A] {
+	return readereither.From0(f)
+}
+
+func From1[T1, A any](f func(context.Context, T1) (A, error)) func(T1) ReaderEither[A] {
+	return readereither.From1(f)
+}
+
+func From2[T1, T2, A any](f func(context.Context, T1, T2) (A, error)) func(T1, T2) ReaderEither[A] {
+	return readereither.From2(f)
+}
+
+func From3[T1, T2, T3, A any](f func(context.Context, T1, T2, T3) (A, error)) func(T1, T2, T3) ReaderEither[A] {
+	return readereither.From3(f)
+}

v2/context/readereither/reader.go

@@ -0,0 +1,94 @@
+// 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 readereither
+
+import (
+	"context"
+
+	"github.com/IBM/fp-go/v2/readereither"
+)
+
+func FromEither[A any](e Either[A]) ReaderEither[A] {
+	return readereither.FromEither[context.Context](e)
+}
+
+func Left[A any](l error) ReaderEither[A] {
+	return readereither.Left[context.Context, A](l)
+}
+
+func Right[A any](r A) ReaderEither[A] {
+	return readereither.Right[context.Context, error](r)
+}
+
+func MonadMap[A, B any](fa ReaderEither[A], f func(A) B) ReaderEither[B] {
+	return readereither.MonadMap(fa, f)
+}
+
+func Map[A, B any](f func(A) B) Operator[A, B] {
+	return readereither.Map[context.Context, error](f)
+}
+
+func MonadChain[A, B any](ma ReaderEither[A], f func(A) ReaderEither[B]) ReaderEither[B] {
+	return readereither.MonadChain(ma, f)
+}
+
+func Chain[A, B any](f func(A) ReaderEither[B]) Operator[A, B] {
+	return readereither.Chain(f)
+}
+
+func Of[A any](a A) ReaderEither[A] {
+	return readereither.Of[context.Context, error](a)
+}
+
+func MonadAp[A, B any](fab ReaderEither[func(A) B], fa ReaderEither[A]) ReaderEither[B] {
+	return readereither.MonadAp(fab, fa)
+}
+
+func Ap[A, B any](fa ReaderEither[A]) func(ReaderEither[func(A) B]) ReaderEither[B] {
+	return readereither.Ap[B](fa)
+}
+
+func FromPredicate[A any](pred func(A) bool, onFalse func(A) error) func(A) ReaderEither[A] {
+	return readereither.FromPredicate[context.Context](pred, onFalse)
+}
+
+func OrElse[A any](onLeft func(error) ReaderEither[A]) func(ReaderEither[A]) ReaderEither[A] {
+	return readereither.OrElse(onLeft)
+}
+
+func Ask() ReaderEither[context.Context] {
+	return readereither.Ask[context.Context, error]()
+}
+
+func MonadChainEitherK[A, B any](ma ReaderEither[A], f func(A) Either[B]) ReaderEither[B] {
+	return readereither.MonadChainEitherK(ma, f)
+}
+
+func ChainEitherK[A, B any](f func(A) Either[B]) func(ma ReaderEither[A]) ReaderEither[B] {
+	return readereither.ChainEitherK[context.Context](f)
+}
+
+func ChainOptionK[A, B any](onNone func() error) func(func(A) Option[B]) Operator[A, B] {
+	return readereither.ChainOptionK[context.Context, A, B](onNone)
+}
+
+func MonadFlap[B, A any](fab ReaderEither[func(A) B], a A) ReaderEither[B] {
+	return readereither.MonadFlap(fab, a)
+}
+
+func Flap[B, A any](a A) Operator[func(A) B, B] {
+	return readereither.Flap[context.Context, error, B](a)
+}

v2/context/readereither/sequence.go

@@ -0,0 +1,39 @@
+// 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 readereither
+
+import (
+	"github.com/IBM/fp-go/v2/readereither"
+	"github.com/IBM/fp-go/v2/tuple"
+)
+
+// SequenceT converts n inputs of higher kinded types into a higher kinded types of n strongly typed values, represented as a tuple
+
+func SequenceT1[A any](a ReaderEither[A]) ReaderEither[tuple.Tuple1[A]] {
+	return readereither.SequenceT1(a)
+}
+
+func SequenceT2[A, B any](a ReaderEither[A], b ReaderEither[B]) ReaderEither[tuple.Tuple2[A, B]] {
+	return readereither.SequenceT2(a, b)
+}
+
+func SequenceT3[A, B, C any](a ReaderEither[A], b ReaderEither[B], c ReaderEither[C]) ReaderEither[tuple.Tuple3[A, B, C]] {
+	return readereither.SequenceT3(a, b, c)
+}
+
+func SequenceT4[A, B, C, D any](a ReaderEither[A], b ReaderEither[B], c ReaderEither[C], d ReaderEither[D]) ReaderEither[tuple.Tuple4[A, B, C, D]] {
+	return readereither.SequenceT4(a, b, c, d)
+}

v2/context/readereither/type.go

@@ -0,0 +1,35 @@
+// 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 readereither implements a specialization of the Reader monad assuming a golang context as the context of the monad and a standard golang error
+package readereither
+
+import (
+	"context"
+
+	"github.com/IBM/fp-go/v2/either"
+	"github.com/IBM/fp-go/v2/option"
+	"github.com/IBM/fp-go/v2/reader"
+	"github.com/IBM/fp-go/v2/readereither"
+)
+
+type (
+	Option[A any] = option.Option[A]
+	Either[A any] = either.Either[error, A]
+	// ReaderEither is a specialization of the Reader monad for the typical golang scenario
+	ReaderEither[A any] = readereither.ReaderEither[context.Context, error, A]
+
+	Operator[A, B any] = reader.Reader[ReaderEither[A], ReaderEither[B]]
+)

v2/context/readerioeither/bind.go

@@ -0,0 +1,89 @@
+// 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 (
+	"github.com/IBM/fp-go/v2/internal/apply"
+	"github.com/IBM/fp-go/v2/internal/chain"
+	"github.com/IBM/fp-go/v2/internal/functor"
+)
+
+// Bind creates an empty context of type [S] to be used with the [Bind] operation
+func Do[S any](
+	empty S,
+) ReaderIOEither[S] {
+	return Of(empty)
+}
+
+// Bind attaches the result of a computation to a context [S1] to produce a context [S2]
+func Bind[S1, S2, T any](
+	setter func(T) func(S1) S2,
+	f func(S1) ReaderIOEither[T],
+) func(ReaderIOEither[S1]) ReaderIOEither[S2] {
+	return chain.Bind(
+		Chain[S1, S2],
+		Map[T, S2],
+		setter,
+		f,
+	)
+}
+
+// Let attaches the result of a computation to a context [S1] to produce a context [S2]
+func Let[S1, S2, T any](
+	setter func(T) func(S1) S2,
+	f func(S1) T,
+) func(ReaderIOEither[S1]) ReaderIOEither[S2] {
+	return functor.Let(
+		Map[S1, S2],
+		setter,
+		f,
+	)
+}
+
+// LetTo attaches the a value to a context [S1] to produce a context [S2]
+func LetTo[S1, S2, T any](
+	setter func(T) func(S1) S2,
+	b T,
+) func(ReaderIOEither[S1]) ReaderIOEither[S2] {
+	return functor.LetTo(
+		Map[S1, S2],
+		setter,
+		b,
+	)
+}
+
+// BindTo initializes a new state [S1] from a value [T]
+func BindTo[S1, T any](
+	setter func(T) S1,
+) func(ReaderIOEither[T]) ReaderIOEither[S1] {
+	return chain.BindTo(
+		Map[T, S1],
+		setter,
+	)
+}
+
+// ApS attaches a value to a context [S1] to produce a context [S2] by considering the context and the value concurrently
+func ApS[S1, S2, T any](
+	setter func(T) func(S1) S2,
+	fa ReaderIOEither[T],
+) func(ReaderIOEither[S1]) ReaderIOEither[S2] {
+	return apply.ApS(
+		Ap[S2, T],
+		Map[S1, func(T) S2],
+		setter,
+		fa,
+	)
+}

v2/context/readerioeither/bind_test.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 readerioeither
+
+import (
+	"context"
+	"testing"
+
+	E "github.com/IBM/fp-go/v2/either"
+	F "github.com/IBM/fp-go/v2/function"
+	"github.com/IBM/fp-go/v2/internal/utils"
+	"github.com/stretchr/testify/assert"
+)
+
+func getLastName(s utils.Initial) ReaderIOEither[string] {
+	return Of("Doe")
+}
+
+func getGivenName(s utils.WithLastName) ReaderIOEither[string] {
+	return Of("John")
+}
+
+func TestBind(t *testing.T) {
+
+	res := F.Pipe3(
+		Do(utils.Empty),
+		Bind(utils.SetLastName, getLastName),
+		Bind(utils.SetGivenName, getGivenName),
+		Map(utils.GetFullName),
+	)
+
+	assert.Equal(t, res(context.Background())(), E.Of[error]("John Doe"))
+}
+
+func TestApS(t *testing.T) {
+
+	res := F.Pipe3(
+		Do(utils.Empty),
+		ApS(utils.SetLastName, Of("Doe")),
+		ApS(utils.SetGivenName, Of("John")),
+		Map(utils.GetFullName),
+	)
+
+	assert.Equal(t, res(context.Background())(), E.Of[error]("John Doe"))
+}

v2/context/readerioeither/bracket.go

@@ -0,0 +1,44 @@
+// 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 (
+	"context"
+
+	"github.com/IBM/fp-go/v2/internal/bracket"
+	"github.com/IBM/fp-go/v2/readerio"
+)
+
+// Bracket makes sure that a resource is cleaned up in the event of an error. The release action is called regardless of
+// whether the body action returns and error or not.
+func Bracket[
+	A, B, ANY any](
+
+	acquire ReaderIOEither[A],
+	use func(A) ReaderIOEither[B],
+	release func(A, Either[B]) ReaderIOEither[ANY],
+) ReaderIOEither[B] {
+	return bracket.Bracket[ReaderIOEither[A], ReaderIOEither[B], ReaderIOEither[ANY], Either[B], A, B](
+		readerio.Of[context.Context, Either[B]],
+		MonadChain[A, B],
+		readerio.MonadChain[context.Context, Either[B], Either[B]],
+		MonadChain[ANY, B],
+
+		acquire,
+		use,
+		release,
+	)
+}

v2/context/readerioeither/cancel.go

@@ -0,0 +1,33 @@
+// 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 (
+	"context"
+
+	CIOE "github.com/IBM/fp-go/v2/context/ioeither"
+	"github.com/IBM/fp-go/v2/ioeither"
+)
+
+// WithContext wraps an existing [ReaderIOEither] and performs a context check for cancellation before delegating
+func WithContext[A any](ma ReaderIOEither[A]) ReaderIOEither[A] {
+	return func(ctx context.Context) IOEither[A] {
+		if err := context.Cause(ctx); err != nil {
+			return ioeither.Left[A](err)
+		}
+		return CIOE.WithContext(ctx, ma(ctx))
+	}
+}