fix: implement simple cache for pure functions

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

README.md

@@ -73,7 +73,7 @@ This library aims to provide a set of data types and functions that make it easy
 
 The library itself also comprises many small functions, but it's admittedly harder to maintain than code that uses it. However this asymmetry is intended because it offloads complexity from users into a central component.
 
-## Comparation to Idiomatic Go
+## Comparison to Idiomatic Go
 
 In this section we discuss how the functional APIs differ from idiomatic go function signatures and how to convert back and forth.
 
@@ -181,7 +181,7 @@ The `Map` operation for `ReaderIOEither` is defined as:
 func Map[R, E, A, B any](f func(A) B) func(fa ReaderIOEither[R, E, A]) ReaderIOEither[R, E, B]
 ```
 
-and in fact the equivalent operations for all other mondas follow the same pattern, we could try to introduce a new type for `ReaderIOEither` (without a parameter) as a HKT, e.g. like so (made-up syntax, does not work in go):
+and in fact the equivalent operations for all other monads follow the same pattern, we could try to introduce a new type for `ReaderIOEither` (without a parameter) as a HKT, e.g. like so (made-up syntax, does not work in go):
 
 ```go
 func Map[HKT, R, E, A, B any](f func(A) B) func(HKT[R, E, A]) HKT[R, E, B]

array/array.go

@@ -304,3 +304,7 @@ func FoldMap[A, B any](m M.Monoid[B]) func(func(A) B) func([]A) B {
 func Fold[A any](m M.Monoid[A]) func([]A) A {
 	return G.Fold[[]A](m)
 }
+
+func Push[A any](a A) func([]A) []A {
+	return G.Push[[]A](a)
+}

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/function"
+	O "github.com/IBM/fp-go/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]
+}

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/function"
+	I "github.com/IBM/fp-go/number/integer"
+	O "github.com/IBM/fp-go/option"
+	"github.com/IBM/fp-go/ord"
+	S "github.com/IBM/fp-go/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}}]
+
+}

array/generic/array.go

@@ -28,6 +28,14 @@ func Of[GA ~[]A, A any](value A) GA {
 	return GA{value}
 }
 
+func Reduce[GA ~[]A, A, B any](fa GA, f func(B, A) B, initial B) B {
+	return array.Reduce(fa, f, initial)
+}
+
+func ReduceWithIndex[GA ~[]A, A, B any](fa GA, f func(int, B, A) B, initial B) B {
+	return array.ReduceWithIndex(fa, f, initial)
+}
+
 // From constructs an array from a set of variadic arguments
 func From[GA ~[]A, A any](data ...A) GA {
 	return data
@@ -105,6 +113,10 @@ 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 F.Bind2nd(MonadMap[GA, GB, A, B], f)
+}
+
 func Size[GA ~[]A, A any](as GA) int {
 	return len(as)
 }
@@ -226,3 +238,7 @@ func Fold[AS ~[]A, A any](m M.Monoid[A]) func(AS) A {
 		return array.Reduce(as, m.Concat, m.Empty())
 	}
 }
+
+func Push[GA ~[]A, A any](a A) func(GA) GA {
+	return F.Bind2nd(array.Push[GA, A], a)
+}

array/generic/sort.go

@@ -45,3 +45,12 @@ func SortByKey[GA ~[]T, K, T any](ord O.Ord[K], f func(T) K) func(ma GA) GA {
 		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],
+	)
+}

array/sort.go

@@ -29,3 +29,8 @@ func Sort[T any](ord O.Ord[T]) func(ma []T) []T {
 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)
+}

cli/tuple.go

@@ -20,6 +20,7 @@ import (
 	"log"
 	"os"
 	"path/filepath"
+	"strings"
 	"time"
 
 	C "github.com/urfave/cli/v2"
@@ -36,8 +37,51 @@ func writeTupleType(f *os.File, symbol string, i int) {
 	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 optionize version
+	// 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++ {
@@ -398,6 +442,10 @@ import (
 		generateToArray(f, i)
 		// generate fromArray
 		generateFromArray(f, i)
+		// generate push
+		if i < count {
+			generatePush(f, i)
+		}
 	}
 
 	return nil

context/readerioeither/gen.go

@@ -2,7 +2,7 @@ package readerioeither
 
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-11 11:37:34.0836986 +0200 CEST m=+0.009764601
+// 2023-08-17 22:58:56.457404 +0200 CEST m=+0.024265101
 
 import (
 	"context"

context/readerioeither/generic/gen.go

@@ -2,7 +2,7 @@ package generic
 
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-11 11:37:34.0838811 +0200 CEST m=+0.009947101
+// 2023-08-17 22:58:56.457404 +0200 CEST m=+0.024265101
 
 import (
 	"context"

either/either.go

@@ -146,8 +146,8 @@ func FromOption[E, A any](onNone func() E) func(O.Option[A]) Either[E, A] {
 	return O.Fold(F.Nullary2(onNone, Left[A, E]), Right[E, A])
 }
 
-func ToOption[E, A any]() func(Either[E, A]) O.Option[A] {
-	return Fold(F.Ignore1of1[E](O.None[A]), O.Some[A])
+func ToOption[E, A any](ma Either[E, A]) O.Option[A] {
+	return MonadFold(ma, F.Ignore1of1[E](O.None[A]), O.Some[A])
 }
 
 func FromError[A any](f func(a A) error) func(A) Either[error, A] {

either/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-11 11:37:35.9608486 +0200 CEST m=+0.009664501
+// 2023-08-17 22:58:57.9925506 +0200 CEST m=+0.033401101
 
 package either
 

function/binds.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-11 11:37:50.171038 +0200 CEST m=+0.031513801
+// 2023-08-17 22:59:01.9404821 +0200 CEST m=+0.161366801
 
 package function
 

function/cache.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 function
+
+import (
+	G "github.com/IBM/fp-go/function/generic"
+)
+
+// Cache converts a unary function into a unary function that caches the value depending on the parameter
+func Cache[K comparable, T any](f func(K) T) func(K) T {
+	return G.Cache(f)
+}
+
+// ContramapCache converts a unary function into a unary function that caches the value depending on the parameter
+func ContramapCache[A any, K comparable, T any](kf func(A) K) func(func(A) T) func(A) T {
+	return G.ContramapCache[func(A) T](kf)
+}

function/cache_test.go

@@ -0,0 +1,50 @@
+// Copyright (c) 2023 IBM Corp.
+// All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package function
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCache(t *testing.T) {
+	var count int
+
+	withSideEffect := func(n int) int {
+		count++
+		return n
+	}
+
+	cached := Cache(withSideEffect)
+
+	assert.Equal(t, 0, count)
+
+	assert.Equal(t, 10, cached(10))
+	assert.Equal(t, 1, count)
+
+	assert.Equal(t, 10, cached(10))
+	assert.Equal(t, 1, count)
+
+	assert.Equal(t, 20, cached(20))
+	assert.Equal(t, 2, count)
+
+	assert.Equal(t, 20, cached(20))
+	assert.Equal(t, 2, count)
+
+	assert.Equal(t, 10, cached(10))
+	assert.Equal(t, 2, count)
+}

function/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-11 11:37:38.4916948 +0200 CEST m=+0.060448601
+// 2023-08-17 22:58:59.8663985 +0200 CEST m=+0.103744101
 
 package function
 

function/generic/cache.go

@@ -0,0 +1,65 @@
+// Copyright (c) 2023 IBM Corp.
+// All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package generic
+
+import (
+	"sync"
+
+	L "github.com/IBM/fp-go/internal/lazy"
+)
+
+// Cache converts a unary function into a unary function that caches the value depending on the parameter
+func Cache[F ~func(K) T, K comparable, T any](f F) F {
+	return ContramapCache[F](func(k K) K { return k })(f)
+}
+
+// ContramapCache converts a unary function into a unary function that caches the value depending on the parameter
+func ContramapCache[F ~func(A) T, KF func(A) K, A any, K comparable, T any](kf KF) func(F) F {
+	return CacheCallback[F](kf, getOrCreate[K, T]())
+}
+
+// getOrCreate is a naive implementation of a cache, without bounds
+func getOrCreate[K comparable, T any]() func(K, func() func() T) func() T {
+	cache := make(map[K]func() T)
+	var l sync.Mutex
+
+	return func(k K, cb func() func() T) func() T {
+		// only lock to access a lazy accessor to the value
+		l.Lock()
+		existing, ok := cache[k]
+		if !ok {
+			existing = cb()
+			cache[k] = existing
+		}
+		l.Unlock()
+		// compute the value outside of the lock
+		return existing
+	}
+}
+
+// CacheCallback converts a unary function into a unary function that caches the value depending on the parameter
+func CacheCallback[F ~func(A) T, KF func(A) K, C ~func(K, func() func() T) func() T, A any, K comparable, T any](kf KF, getOrCreate C) func(F) F {
+	return func(f F) F {
+		return func(a A) T {
+			// cache entry
+			return getOrCreate(kf(a), func() func() T {
+				return L.Memoize[func() T](func() T {
+					return f(a)
+				})
+			})()
+		}
+	}
+}

identity/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-11 11:38:00.2678592 +0200 CEST m=+0.008890401
+// 2023-08-17 22:59:06.2987136 +0200 CEST m=+0.049156901
 
 package identity
 

internal/apply/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-11 11:38:01.6948567 +0200 CEST m=+0.013530301
+// 2023-08-17 22:59:08.1313362 +0200 CEST m=+0.111171801
 
 package apply
 

internal/array/array.go

@@ -42,10 +42,27 @@ func Reduce[GA ~[]A, A, B any](fa GA, f func(B, A) B, initial B) B {
 	return current
 }
 
+func ReduceWithIndex[GA ~[]A, A, B any](fa GA, f func(int, B, A) B, initial B) B {
+	current := initial
+	count := len(fa)
+	for i := 0; i < count; i++ {
+		current = f(i, current, fa[i])
+	}
+	return current
+}
+
 func Append[GA ~[]A, A any](as GA, a A) GA {
 	return append(as, a)
 }
 
+func Push[GA ~[]A, A any](as GA, a A) GA {
+	l := len(as)
+	cpy := make(GA, l+1)
+	copy(cpy, as)
+	cpy[l] = a
+	return cpy
+}
+
 func Empty[GA ~[]A, A any]() GA {
 	return make(GA, 0)
 }

internal/bindt/bind.go

@@ -0,0 +1,75 @@
+// 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 bindt
+
+import (
+	F "github.com/IBM/fp-go/function"
+	I "github.com/IBM/fp-go/identity"
+	T "github.com/IBM/fp-go/tuple"
+)
+
+func Bind[SET ~func(B) func(S1) S2, FCT ~func(S1) HKTB, S1, S2, B, HKTS1, HKTS2, HKTB any](
+	mchain func(func(S1) HKTS2) func(HKTS1) HKTS2,
+	mmap func(func(B) S2) func(HKTB) HKTS2,
+	s SET,
+	f FCT,
+) func(HKTS1) HKTS2 {
+	return mchain(F.Flow3(
+		T.Replicate2[S1],
+		T.Map2(F.Flow2(
+			I.Ap[S2, S1],
+			F.Flow2(
+				F.Bind1st(F.Flow2[SET, func(func(S1) S2) S2], s),
+				mmap,
+			)), f),
+		T.Tupled2(I.MonadAp[HKTS2, HKTB]),
+	))
+}
+
+func BindTo[SET ~func(B) S2, S2, B, HKTS2, HKTB any](
+	mmap func(func(B) S2) func(HKTB) HKTS2,
+	s SET,
+) func(HKTB) HKTS2 {
+	return mmap(s)
+}
+
+func ApS[
+	SET ~func(B) func(S1) S2,
+	S1, S2, B, HKTS1S2, HKTS1, HKTS2, HKTB any,
+](
+	ap func(HKTS1) func(HKTS1S2) HKTS2,
+	mmap func(func(B) func(S1) S2) func(HKTB) HKTS1S2,
+	s SET, fb HKTB) func(HKTS1) HKTS2 {
+
+	return F.Flow2(
+		ap,
+		I.Ap[HKTS2, HKTS1S2](mmap(s)(fb)),
+	)
+}
+
+func Let[SET ~func(B) func(S1) S2, FCT ~func(S1) B, S1, S2, B, HKTS1, HKTS2 any](
+	mmap func(func(S1) S2) func(HKTS1) HKTS2,
+	s SET,
+	f FCT,
+) func(HKTS1) HKTS2 {
+	return mmap(F.Flow3(
+		T.Replicate2[S1],
+		T.Map2(F.Flow2(
+			I.Ap[S2, S1],
+			F.Bind1st(F.Flow2[SET, func(func(S1) S2) S2], s)), f),
+		T.Tupled2(I.MonadAp[S2, B]),
+	))
+}

internal/lazy/memoize.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 lazy
+
+import "sync"
+
+// Memoize computes the value of the provided IO monad lazily but exactly once
+func Memoize[GA ~func() A, A any](ma GA) GA {
+	// synchronization primitives
+	var once sync.Once
+	var result A
+	// callback
+	gen := func() {
+		result = ma()
+	}
+	// returns our memoized wrapper
+	return func() A {
+		once.Do(gen)
+		return result
+	}
+}

io/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-11 11:38:07.3305497 +0200 CEST m=+0.014821301
+// 2023-08-17 22:59:10.1040409 +0200 CEST m=+0.089470201
 
 package io
 

io/generic/ap.go

@@ -64,6 +64,28 @@ func MonadApFirst[GA ~func() A, GB ~func() B, GBA ~func() func(B) A, A, B any](f
 	)
 }
 
+// MonadApFirstPar combines two effectful actions, keeping only the result of the first.
+func MonadApFirstPar[GA ~func() A, GB ~func() B, GBA ~func() func(B) A, A, B any](first GA, second GB) GA {
+	return G.MonadApFirst(
+		MonadApPar[GB, GA, GBA, B, A],
+		MonadMap[GA, GBA, A, func(B) A],
+
+		first,
+		second,
+	)
+}
+
+// MonadApFirstSeq combines two effectful actions, keeping only the result of the first.
+func MonadApFirstSeq[GA ~func() A, GB ~func() B, GBA ~func() func(B) A, A, B any](first GA, second GB) GA {
+	return G.MonadApFirst(
+		MonadApSeq[GB, GA, GBA, B, A],
+		MonadMap[GA, GBA, A, func(B) A],
+
+		first,
+		second,
+	)
+}
+
 // ApFirst combines two effectful actions, keeping only the result of the first.
 func ApFirst[GA ~func() A, GB ~func() B, GBA ~func() func(B) A, A, B any](second GB) func(GA) GA {
 	return G.ApFirst(
@@ -74,6 +96,26 @@ func ApFirst[GA ~func() A, GB ~func() B, GBA ~func() func(B) A, A, B any](second
 	)
 }
 
+// ApFirstPar combines two effectful actions, keeping only the result of the first.
+func ApFirstPar[GA ~func() A, GB ~func() B, GBA ~func() func(B) A, A, B any](second GB) func(GA) GA {
+	return G.ApFirst(
+		MonadApPar[GB, GA, GBA, B, A],
+		MonadMap[GA, GBA, A, func(B) A],
+
+		second,
+	)
+}
+
+// ApFirstSeq combines two effectful actions, keeping only the result of the first.
+func ApFirstSeq[GA ~func() A, GB ~func() B, GBA ~func() func(B) A, A, B any](second GB) func(GA) GA {
+	return G.ApFirst(
+		MonadApSeq[GB, GA, GBA, B, A],
+		MonadMap[GA, GBA, A, func(B) A],
+
+		second,
+	)
+}
+
 // MonadApSecond combines two effectful actions, keeping only the result of the second.
 func MonadApSecond[GA ~func() A, GB ~func() B, GBB ~func() func(B) B, A, B any](first GA, second GB) GB {
 	return G.MonadApSecond(

io/generic/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-11 11:38:07.3305497 +0200 CEST m=+0.014821301
+// 2023-08-17 22:59:10.1132645 +0200 CEST m=+0.098693801
 package generic
 
 import (

io/generic/io.go

@@ -16,11 +16,11 @@
 package generic
 
 import (
-	"sync"
 	"time"
 
 	F "github.com/IBM/fp-go/function"
 	C "github.com/IBM/fp-go/internal/chain"
+	L "github.com/IBM/fp-go/internal/lazy"
 )
 
 // type IO[A any] = func() A
@@ -119,18 +119,7 @@ func Flatten[GA ~func() A, GAA ~func() GA, A any](mma GAA) GA {
 
 // Memoize computes the value of the provided IO monad lazily but exactly once
 func Memoize[GA ~func() A, A any](ma GA) GA {
-	// synchronization primitives
-	var once sync.Once
-	var result A
-	// callback
-	gen := func() {
-		result = ma()
-	}
-	// returns our memoized wrapper
-	return func() A {
-		once.Do(gen)
-		return result
-	}
+	return L.Memoize[GA, A](ma)
 }
 
 // Delay creates an operation that passes in the value after some delay

ioeither/bind.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 ioeither
+
+import (
+	G "github.com/IBM/fp-go/ioeither/generic"
+)
+
+// Bind applies a function to an input state and merges the result into that state
+func Bind[E, A, S1, S2 any](s func(A) func(S1) S2, f func(S1) IOEither[E, A]) func(IOEither[E, S1]) IOEither[E, S2] {
+	return G.Bind[IOEither[E, S1], IOEither[E, S2], IOEither[E, A], func(S1) IOEither[E, A]](s, f)
+}
+
+// BindTo initializes some state based on a value
+func BindTo[
+	E, A, S2 any](s func(A) S2) func(IOEither[E, A]) IOEither[E, S2] {
+	return G.BindTo[IOEither[E, S2], IOEither[E, A]](s)
+}
+
+func ApS[
+	E, A, S1, S2 any,
+](s func(A) func(S1) S2, fa IOEither[E, A]) func(IOEither[E, S1]) IOEither[E, S2] {
+	return G.ApS[IOEither[E, S1], IOEither[E, S2], IOEither[E, A], IOEither[E, func(S1) S2]](s, fa)
+}
+
+func Let[E, A, S1, S2 any](
+	s func(A) func(S1) S2,
+	f func(S1) A,
+) func(IOEither[E, S1]) IOEither[E, S2] {
+	return G.Let[IOEither[E, S1], IOEither[E, S2]](s, f)
+}

ioeither/examples_create_test.go

@@ -0,0 +1,57 @@
+// Copyright (c) 2023 IBM Corp.
+// All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ioeither
+
+import (
+	"fmt"
+
+	E "github.com/IBM/fp-go/either"
+)
+
+func ExampleIOEither_creation() {
+	// Build an IOEither
+	leftValue := Left[string](fmt.Errorf("some error"))
+	rightValue := Right[error]("value")
+
+	// Convert from Either
+	eitherValue := E.Of[error](42)
+	ioFromEither := FromEither(eitherValue)
+
+	// some predicate
+	isEven := func(num int) (int, error) {
+		if num%2 == 0 {
+			return num, nil
+		}
+		return 0, fmt.Errorf("%d is an odd number", num)
+	}
+	fromEven := Eitherize1(isEven)
+	leftFromPred := fromEven(3)
+	rightFromPred := fromEven(4)
+
+	fmt.Println(leftValue())
+	fmt.Println(rightValue())
+	fmt.Println(ioFromEither())
+	fmt.Println(leftFromPred())
+	fmt.Println(rightFromPred())
+
+	// Output:
+	// Left[*errors.errorString, string](some error)
+	// Right[<nil>, string](value)
+	// Right[<nil>, int](42)
+	// Left[*errors.errorString, int](3 is an odd number)
+	// Right[<nil>, int](4)
+
+}

ioeither/examples_do_test.go

@@ -0,0 +1,57 @@
+// Copyright (c) 2023 IBM Corp.
+// All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ioeither
+
+import (
+	"fmt"
+	"log"
+
+	F "github.com/IBM/fp-go/function"
+	IO "github.com/IBM/fp-go/io"
+	T "github.com/IBM/fp-go/tuple"
+)
+
+func ExampleIOEither_do() {
+	foo := Of[error]("foo")
+	bar := Of[error](1)
+
+	// quux consumes the state of three bindings and returns an [IO] instead of an [IOEither]
+	quux := func(t T.Tuple3[string, int, string]) IO.IO[any] {
+		return IO.FromImpure(func() {
+			log.Printf("t1: %s, t2: %d, t3: %s", t.F1, t.F2, t.F3)
+		})
+	}
+
+	transform := func(t T.Tuple3[string, int, string]) int {
+		return len(t.F1) + t.F2 + len(t.F3)
+	}
+
+	b := F.Pipe5(
+		foo,
+		BindTo[error](T.Of[string]),
+		ApS(T.Push1[string, int], bar),
+		Bind(T.Push2[string, int, string], func(t T.Tuple2[string, int]) IOEither[error, string] {
+			return Of[error](fmt.Sprintf("%s%d", t.F1, t.F2))
+		}),
+		ChainFirstIOK[error](quux),
+		Map[error](transform),
+	)
+
+	fmt.Println(b())
+
+	// Output:
+	// Right[<nil>, int](8)
+}

ioeither/examples_extract_test.go

@@ -0,0 +1,45 @@
+// Copyright (c) 2023 IBM Corp.
+// All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ioeither
+
+import (
+	"fmt"
+
+	E "github.com/IBM/fp-go/either"
+	F "github.com/IBM/fp-go/function"
+	IO "github.com/IBM/fp-go/io"
+)
+
+func ExampleIOEither_extraction() {
+	// IOEither
+	someIOEither := Right[error](42)
+	eitherValue := someIOEither()                            // E.Right(42)
+	value := E.GetOrElse(F.Constant1[error](0))(eitherValue) // 42
+
+	// Or more directly
+	infaillibleIO := GetOrElse(F.Constant1[error](IO.Of(0)))(someIOEither) // => IO.Right(42)
+	valueFromIO := infaillibleIO()                                         // => 42
+
+	fmt.Println(eitherValue)
+	fmt.Println(value)
+	fmt.Println(valueFromIO)
+
+	// Output:
+	// Right[<nil>, int](42)
+	// 42
+	// 42
+
+}

ioeither/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-11 11:38:09.4187123 +0200 CEST m=+0.099620101
+// 2023-08-17 22:59:12.0033119 +0200 CEST m=+0.096740401
 
 package ioeither
 

ioeither/generic/bind.go

@@ -0,0 +1,79 @@
+// Copyright (c) 2023 IBM Corp.
+// All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package generic
+
+import (
+	ET "github.com/IBM/fp-go/either"
+	G "github.com/IBM/fp-go/internal/bindt"
+)
+
+// Bind applies a function to an input state and merges the result into that state
+func Bind[
+	GS1 ~func() ET.Either[E, S1],
+	GS2 ~func() ET.Either[E, S2],
+	GA ~func() ET.Either[E, A],
+	FCT ~func(S1) GA,
+	E any,
+	SET ~func(A) func(S1) S2,
+	A, S1, S2 any](s SET, f FCT) func(GS1) GS2 {
+	return G.Bind(
+		Chain[GS1, GS2, E, S1, S2],
+		Map[GA, GS2, E, A, S2],
+		s,
+		f,
+	)
+}
+
+// BindTo initializes some state based on a value
+func BindTo[
+	GS2 ~func() ET.Either[E, S2],
+	GA ~func() ET.Either[E, A],
+	E any,
+	SET ~func(A) S2,
+	A, S2 any](s SET) func(GA) GS2 {
+	return G.BindTo(
+		Map[GA, GS2, E, A, S2],
+		s,
+	)
+}
+
+func ApS[
+	GS1 ~func() ET.Either[E, S1],
+	GS2 ~func() ET.Either[E, S2],
+	GB ~func() ET.Either[E, B],
+	GS1S2 ~func() ET.Either[E, func(S1) S2],
+	SET ~func(B) func(S1) S2,
+	E, S1, S2, B any,
+](s SET, fb GB) func(GS1) GS2 {
+	return G.ApS[SET, S1, S2, B, GS1S2, GS1, GS2, GB](
+		Ap[GS2, GS1S2, GS1, E, S1, S2],
+		Map[GB, GS1S2, E, B, func(S1) S2],
+		s,
+		fb,
+	)
+}
+
+func Let[
+	GS1 ~func() ET.Either[E, S1],
+	GS2 ~func() ET.Either[E, S2],
+	SET ~func(B) func(S1) S2,
+	FCT ~func(S1) B,
+	E, S1, S2, B any](
+	s SET,
+	f FCT,
+) func(GS1) GS2 {
+	return G.Let[SET, FCT, S1, S2, B, GS1, GS2](Map[GS1, GS2, E, S1, S2], s, f)
+}

ioeither/generic/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-11 11:38:09.4489926 +0200 CEST m=+0.129900401
+// 2023-08-17 22:59:12.0246635 +0200 CEST m=+0.118092001
 package generic
 
 import (

iooption/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-11 11:38:12.1021634 +0200 CEST m=+0.041956701
+// 2023-08-17 22:59:14.0582736 +0200 CEST m=+0.248503201
 
 package iooption
 

iooption/generic/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-11 11:38:12.1210201 +0200 CEST m=+0.060813401
+// 2023-08-17 22:59:14.0642289 +0200 CEST m=+0.254458501
 package generic
 
 import (

iterator/stateless/generic/reflect.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 generic
+
+import (
+	R "reflect"
+
+	F "github.com/IBM/fp-go/function"
+	LG "github.com/IBM/fp-go/io/generic"
+	L "github.com/IBM/fp-go/lazy"
+	N "github.com/IBM/fp-go/number"
+	I "github.com/IBM/fp-go/number/integer"
+	O "github.com/IBM/fp-go/option"
+	T "github.com/IBM/fp-go/tuple"
+)
+
+func FromReflect[GR ~func() O.Option[T.Tuple2[GR, R.Value]]](val R.Value) GR {
+	// recursive callback
+	var recurse func(idx int) GR
+
+	// limits the index
+	fromPred := O.FromPredicate(I.Between(0, val.Len()))
+
+	recurse = func(idx int) GR {
+		return F.Pipe3(
+			idx,
+			L.Of[int],
+			L.Map(fromPred),
+			LG.Map[L.Lazy[O.Option[int]], GR](O.Map(
+				F.Flow2(
+					T.Replicate2[int],
+					T.Map2(F.Flow2(N.Add(1), recurse), val.Index),
+				),
+			)),
+		)
+	}
+
+	// start the recursion
+	return recurse(0)
+}

iterator/stateless/reflect.go

@@ -0,0 +1,27 @@
+// Copyright (c) 2023 IBM Corp.
+// All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package stateless
+
+import (
+	R "reflect"
+
+	G "github.com/IBM/fp-go/iterator/stateless/generic"
+)
+
+// FromReflect creates an iterator that can iterate over types that define [R.Index] and [R.Len]
+func FromReflect(val R.Value) Iterator[R.Value] {
+	return G.FromReflect[Iterator[R.Value]](val)
+}

iterator/stateless/reflect_test.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 stateless
+
+import (
+	"reflect"
+	"testing"
+
+	A "github.com/IBM/fp-go/array"
+	F "github.com/IBM/fp-go/function"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestReflect(t *testing.T) {
+	ar := A.From("a", "b", "c")
+
+	res := F.Pipe3(
+		reflect.ValueOf(ar),
+		FromReflect,
+		ToArray[reflect.Value],
+		A.Map(reflect.Value.String),
+	)
+
+	assert.Equal(t, ar, res)
+}

json/type.go

@@ -32,6 +32,6 @@ func ToTypeE[A any](src any) E.Either[error, A] {
 func ToTypeO[A any](src any) O.Option[A] {
 	return F.Pipe1(
 		ToTypeE[A](src),
-		E.ToOption[error, A](),
+		E.ToOption[error, A],
 	)
 }

lazy/example_lazy_test.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 lazy
+
+import (
+	"fmt"
+	"strconv"
+
+	F "github.com/IBM/fp-go/function"
+)
+
+func ExampleLazy_creation() {
+	// lazy function of a constant value
+	val := Of(42)
+	// create another function to transform this
+	valS := F.Pipe1(
+		val,
+		Map(strconv.Itoa),
+	)
+
+	fmt.Println(valS())
+
+	// Output:
+	// 42
+}

lazy/lazy.go

@@ -72,18 +72,18 @@ func Chain[A, B any](f func(A) Lazy[B]) func(Lazy[A]) Lazy[B] {
 }
 
 func MonadAp[B, A any](mab Lazy[func(A) B], ma Lazy[A]) Lazy[B] {
-	return G.MonadAp[Lazy[A], Lazy[B]](mab, ma)
+	return G.MonadApSeq[Lazy[A], Lazy[B]](mab, ma)
 }
 
 func Ap[B, A any](ma Lazy[A]) func(Lazy[func(A) B]) Lazy[B] {
-	return G.Ap[Lazy[B], Lazy[func(A) B], Lazy[A]](ma)
+	return G.ApSeq[Lazy[B], Lazy[func(A) B], Lazy[A]](ma)
 }
 
 func Flatten[A any](mma Lazy[Lazy[A]]) Lazy[A] {
 	return G.Flatten(mma)
 }
 
-// Memoize computes the value of the provided IO monad lazily but exactly once
+// Memoize computes the value of the provided [Lazy] monad lazily but exactly once
 func Memoize[A any](ma Lazy[A]) Lazy[A] {
 	return G.Memoize(ma)
 }

option/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-11 11:38:14.9503867 +0200 CEST m=+0.020206701
+// 2023-08-17 22:59:16.3450991 +0200 CEST m=+0.104894201
 
 package option
 

option/ord.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 option
+
+import (
+	C "github.com/IBM/fp-go/constraints"
+	F "github.com/IBM/fp-go/function"
+	"github.com/IBM/fp-go/ord"
+)
+
+// Constructs an order for [Option]
+func Ord[A any](a ord.Ord[A]) ord.Ord[Option[A]] {
+	// some convenient shortcuts
+	fld := Fold(
+		F.Constant(Fold(F.Constant(0), F.Constant1[A](-1))),
+		F.Flow2(F.Curry2(a.Compare), F.Bind1st(Fold[A, int], F.Constant(1))),
+	)
+	// convert to an ordering predicate
+	return ord.MakeOrd(F.Uncurry2(fld), Eq(ord.ToEq(a)).Equals)
+}
+
+// FromStrictCompare constructs an [Ord] from the canonical comparison function
+func FromStrictCompare[A C.Ordered]() ord.Ord[Option[A]] {
+	return Ord(ord.FromStrictCompare[A]())
+}

option/ord_test.go

@@ -0,0 +1,46 @@
+// 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 option
+
+import (
+	"testing"
+
+	S "github.com/IBM/fp-go/string"
+	"github.com/stretchr/testify/assert"
+)
+
+// it('getOrd', () => {
+//     const OS = _.getOrd(S.Ord)
+//     U.deepStrictEqual(OS.compare(_.none, _.none), 0)
+//     U.deepStrictEqual(OS.compare(_.some('a'), _.none), 1)
+//     U.deepStrictEqual(OS.compare(_.none, _.some('a')), -1)
+//     U.deepStrictEqual(OS.compare(_.some('a'), _.some('a')), 0)
+//     U.deepStrictEqual(OS.compare(_.some('a'), _.some('b')), -1)
+//     U.deepStrictEqual(OS.compare(_.some('b'), _.some('a')), 1)
+//   })
+
+func TestOrd(t *testing.T) {
+
+	os := Ord(S.Ord)
+
+	assert.Equal(t, 0, os.Compare(None[string](), None[string]()))
+	assert.Equal(t, 1, os.Compare(Some("a"), None[string]()))
+	assert.Equal(t, -1, os.Compare(None[string](), Some("a")))
+	assert.Equal(t, 0, os.Compare(Some("a"), Some("a")))
+	assert.Equal(t, -1, os.Compare(Some("a"), Some("b")))
+	assert.Equal(t, 1, os.Compare(Some("b"), Some("a")))
+
+}

ord/ord.go

@@ -40,6 +40,11 @@ func (self ord[T]) Compare(x, y T) int {
 	return self.c(x, y)
 }
 
+// ToEq converts an [Ord] to [E.Eq]
+func ToEq[T any](o Ord[T]) E.Eq[T] {
+	return o
+}
+
 // MakeOrd creates an instance of an Ord
 func MakeOrd[T any](c func(x, y T) int, e func(x, y T) bool) Ord[T] {
 	return ord[T]{c: c, e: e}

reader/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-11 11:38:23.1396887 +0200 CEST m=+0.020805301
+// 2023-08-17 22:59:18.4448291 +0200 CEST m=+0.161369001
 
 package reader
 

reader/generic/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-11 11:38:23.1402159 +0200 CEST m=+0.021332501
+// 2023-08-17 22:59:18.5047315 +0200 CEST m=+0.221271401
 package generic
 
 // From0 converts a function with 1 parameters returning a [R] into a function with 0 parameters returning a [GRA]

readerioeither/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-11 11:38:26.9546728 +0200 CEST m=+0.032178301
+// 2023-08-17 22:59:21.3704716 +0200 CEST m=+0.110126101
 
 package readerioeither
 

readerioeither/generic/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-11 11:38:26.9556725 +0200 CEST m=+0.033178001
+// 2023-08-17 22:59:21.3811525 +0200 CEST m=+0.120807001
 package generic
 
 import (

record/record.go

@@ -98,7 +98,7 @@ func MapRefWithIndex[K comparable, V, R any](f func(K, *V) R) func(map[K]V) map[
 }
 
 // Lookup returns the entry for a key in a map if it exists
-func Lookup[K comparable, V any](k K) func(map[K]V) O.Option[V] {
+func Lookup[V any, K comparable](k K) func(map[K]V) O.Option[V] {
 	return G.Lookup[map[K]V](k)
 }
 

record/record_test.go

@@ -71,8 +71,8 @@ func TestLookup(t *testing.T) {
 		"b": "b",
 		"c": "c",
 	}
-	assert.Equal(t, O.Some("a"), Lookup[string, string]("a")(data))
-	assert.Equal(t, O.None[string](), Lookup[string, string]("a1")(data))
+	assert.Equal(t, O.Some("a"), Lookup[string]("a")(data))
+	assert.Equal(t, O.None[string](), Lookup[string]("a1")(data))
 }
 
 func TestFilterChain(t *testing.T) {

reflect/generic/reflect.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 generic
+
+import (
+	R "reflect"
+)
+
+func Map[GA ~[]A, A any](f func(R.Value) A) func(R.Value) GA {
+	return func(val R.Value) GA {
+		l := val.Len()
+		res := make(GA, l)
+		for i := l - 1; i >= 0; i-- {
+			res[i] = f(val.Index(i))
+		}
+		return res
+	}
+}

reflect/reflect.go

@@ -0,0 +1,42 @@
+// Copyright (c) 2023 IBM Corp.
+// All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package option
+
+import (
+	R "reflect"
+
+	F "github.com/IBM/fp-go/function"
+	G "github.com/IBM/fp-go/reflect/generic"
+)
+
+func ReduceWithIndex[A any](f func(int, A, R.Value) A, initial A) func(R.Value) A {
+	return func(val R.Value) A {
+		count := val.Len()
+		current := initial
+		for i := 0; i < count; i++ {
+			current = f(i, current, val.Index(i))
+		}
+		return current
+	}
+}
+
+func Reduce[A any](f func(A, R.Value) A, initial A) func(R.Value) A {
+	return ReduceWithIndex(F.Ignore1of3[int](f), initial)
+}
+
+func Map[A any](f func(R.Value) A) func(R.Value) []A {
+	return G.Map[[]A](f)
+}

tuple/gen.go

@@ -1,6 +1,6 @@
 // Code generated by go generate; DO NOT EDIT.
 // This file was generated by robots at
-// 2023-08-11 11:38:30.5947727 +0200 CEST m=+0.033600301
+// 2023-08-17 22:59:23.6923568 +0200 CEST m=+0.056359401
 
 package tuple
 
@@ -205,6 +205,13 @@ func FromArray1[F1 ~func(R) T1, T1, R any](f1 F1) func(r []R) Tuple1[T1] {
 	}
 }
 
+// Push1 creates a [Tuple2] from a [Tuple1] by appending a constant value
+func Push1[T1, T2 any](value T2) func(Tuple1[T1]) Tuple2[T1, T2] {
+	return func(t Tuple1[T1]) Tuple2[T1, T2] {
+		return MakeTuple2(t.F1, value)
+	}
+}
+
 // MakeTuple2 is a function that converts its 2 parameters into a [Tuple2]
 func MakeTuple2[T1, T2 any](t1 T1, t2 T2) Tuple2[T1, T2] {
 	return Tuple2[T1, T2]{t1, t2}
@@ -315,6 +322,13 @@ func FromArray2[F1 ~func(R) T1, F2 ~func(R) T2, T1, T2, R any](f1 F1, f2 F2) fun
 	}
 }
 
+// Push2 creates a [Tuple3] from a [Tuple2] by appending a constant value
+func Push2[T1, T2, T3 any](value T3) func(Tuple2[T1, T2]) Tuple3[T1, T2, T3] {
+	return func(t Tuple2[T1, T2]) Tuple3[T1, T2, T3] {
+		return MakeTuple3(t.F1, t.F2, value)
+	}
+}
+
 // MakeTuple3 is a function that converts its 3 parameters into a [Tuple3]
 func MakeTuple3[T1, T2, T3 any](t1 T1, t2 T2, t3 T3) Tuple3[T1, T2, T3] {
 	return Tuple3[T1, T2, T3]{t1, t2, t3}
@@ -436,6 +450,13 @@ func FromArray3[F1 ~func(R) T1, F2 ~func(R) T2, F3 ~func(R) T3, T1, T2, T3, R an
 	}
 }
 
+// Push3 creates a [Tuple4] from a [Tuple3] by appending a constant value
+func Push3[T1, T2, T3, T4 any](value T4) func(Tuple3[T1, T2, T3]) Tuple4[T1, T2, T3, T4] {
+	return func(t Tuple3[T1, T2, T3]) Tuple4[T1, T2, T3, T4] {
+		return MakeTuple4(t.F1, t.F2, t.F3, value)
+	}
+}
+
 // MakeTuple4 is a function that converts its 4 parameters into a [Tuple4]
 func MakeTuple4[T1, T2, T3, T4 any](t1 T1, t2 T2, t3 T3, t4 T4) Tuple4[T1, T2, T3, T4] {
 	return Tuple4[T1, T2, T3, T4]{t1, t2, t3, t4}
@@ -568,6 +589,13 @@ func FromArray4[F1 ~func(R) T1, F2 ~func(R) T2, F3 ~func(R) T3, F4 ~func(R) T4,
 	}
 }
 
+// Push4 creates a [Tuple5] from a [Tuple4] by appending a constant value
+func Push4[T1, T2, T3, T4, T5 any](value T5) func(Tuple4[T1, T2, T3, T4]) Tuple5[T1, T2, T3, T4, T5] {
+	return func(t Tuple4[T1, T2, T3, T4]) Tuple5[T1, T2, T3, T4, T5] {
+		return MakeTuple5(t.F1, t.F2, t.F3, t.F4, value)
+	}
+}
+
 // MakeTuple5 is a function that converts its 5 parameters into a [Tuple5]
 func MakeTuple5[T1, T2, T3, T4, T5 any](t1 T1, t2 T2, t3 T3, t4 T4, t5 T5) Tuple5[T1, T2, T3, T4, T5] {
 	return Tuple5[T1, T2, T3, T4, T5]{t1, t2, t3, t4, t5}
@@ -711,6 +739,13 @@ func FromArray5[F1 ~func(R) T1, F2 ~func(R) T2, F3 ~func(R) T3, F4 ~func(R) T4,
 	}
 }
 
+// Push5 creates a [Tuple6] from a [Tuple5] by appending a constant value
+func Push5[T1, T2, T3, T4, T5, T6 any](value T6) func(Tuple5[T1, T2, T3, T4, T5]) Tuple6[T1, T2, T3, T4, T5, T6] {
+	return func(t Tuple5[T1, T2, T3, T4, T5]) Tuple6[T1, T2, T3, T4, T5, T6] {
+		return MakeTuple6(t.F1, t.F2, t.F3, t.F4, t.F5, value)
+	}
+}
+
 // MakeTuple6 is a function that converts its 6 parameters into a [Tuple6]
 func MakeTuple6[T1, T2, T3, T4, T5, T6 any](t1 T1, t2 T2, t3 T3, t4 T4, t5 T5, t6 T6) Tuple6[T1, T2, T3, T4, T5, T6] {
 	return Tuple6[T1, T2, T3, T4, T5, T6]{t1, t2, t3, t4, t5, t6}
@@ -865,6 +900,13 @@ func FromArray6[F1 ~func(R) T1, F2 ~func(R) T2, F3 ~func(R) T3, F4 ~func(R) T4,
 	}
 }
 
+// Push6 creates a [Tuple7] from a [Tuple6] by appending a constant value
+func Push6[T1, T2, T3, T4, T5, T6, T7 any](value T7) func(Tuple6[T1, T2, T3, T4, T5, T6]) Tuple7[T1, T2, T3, T4, T5, T6, T7] {
+	return func(t Tuple6[T1, T2, T3, T4, T5, T6]) Tuple7[T1, T2, T3, T4, T5, T6, T7] {
+		return MakeTuple7(t.F1, t.F2, t.F3, t.F4, t.F5, t.F6, value)
+	}
+}
+
 // MakeTuple7 is a function that converts its 7 parameters into a [Tuple7]
 func MakeTuple7[T1, T2, T3, T4, T5, T6, T7 any](t1 T1, t2 T2, t3 T3, t4 T4, t5 T5, t6 T6, t7 T7) Tuple7[T1, T2, T3, T4, T5, T6, T7] {
 	return Tuple7[T1, T2, T3, T4, T5, T6, T7]{t1, t2, t3, t4, t5, t6, t7}
@@ -1030,6 +1072,13 @@ func FromArray7[F1 ~func(R) T1, F2 ~func(R) T2, F3 ~func(R) T3, F4 ~func(R) T4,
 	}
 }
 
+// Push7 creates a [Tuple8] from a [Tuple7] by appending a constant value
+func Push7[T1, T2, T3, T4, T5, T6, T7, T8 any](value T8) func(Tuple7[T1, T2, T3, T4, T5, T6, T7]) Tuple8[T1, T2, T3, T4, T5, T6, T7, T8] {
+	return func(t Tuple7[T1, T2, T3, T4, T5, T6, T7]) Tuple8[T1, T2, T3, T4, T5, T6, T7, T8] {
+		return MakeTuple8(t.F1, t.F2, t.F3, t.F4, t.F5, t.F6, t.F7, value)
+	}
+}
+
 // MakeTuple8 is a function that converts its 8 parameters into a [Tuple8]
 func MakeTuple8[T1, T2, T3, T4, T5, T6, T7, T8 any](t1 T1, t2 T2, t3 T3, t4 T4, t5 T5, t6 T6, t7 T7, t8 T8) Tuple8[T1, T2, T3, T4, T5, T6, T7, T8] {
 	return Tuple8[T1, T2, T3, T4, T5, T6, T7, T8]{t1, t2, t3, t4, t5, t6, t7, t8}
@@ -1206,6 +1255,13 @@ func FromArray8[F1 ~func(R) T1, F2 ~func(R) T2, F3 ~func(R) T3, F4 ~func(R) T4,
 	}
 }
 
+// Push8 creates a [Tuple9] from a [Tuple8] by appending a constant value
+func Push8[T1, T2, T3, T4, T5, T6, T7, T8, T9 any](value T9) func(Tuple8[T1, T2, T3, T4, T5, T6, T7, T8]) Tuple9[T1, T2, T3, T4, T5, T6, T7, T8, T9] {
+	return func(t Tuple8[T1, T2, T3, T4, T5, T6, T7, T8]) Tuple9[T1, T2, T3, T4, T5, T6, T7, T8, T9] {
+		return MakeTuple9(t.F1, t.F2, t.F3, t.F4, t.F5, t.F6, t.F7, t.F8, value)
+	}
+}
+
 // MakeTuple9 is a function that converts its 9 parameters into a [Tuple9]
 func MakeTuple9[T1, T2, T3, T4, T5, T6, T7, T8, T9 any](t1 T1, t2 T2, t3 T3, t4 T4, t5 T5, t6 T6, t7 T7, t8 T8, t9 T9) Tuple9[T1, T2, T3, T4, T5, T6, T7, T8, T9] {
 	return Tuple9[T1, T2, T3, T4, T5, T6, T7, T8, T9]{t1, t2, t3, t4, t5, t6, t7, t8, t9}
@@ -1393,6 +1449,13 @@ func FromArray9[F1 ~func(R) T1, F2 ~func(R) T2, F3 ~func(R) T3, F4 ~func(R) T4,
 	}
 }
 
+// Push9 creates a [Tuple10] from a [Tuple9] by appending a constant value
+func Push9[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10 any](value T10) func(Tuple9[T1, T2, T3, T4, T5, T6, T7, T8, T9]) Tuple10[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10] {
+	return func(t Tuple9[T1, T2, T3, T4, T5, T6, T7, T8, T9]) Tuple10[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10] {
+		return MakeTuple10(t.F1, t.F2, t.F3, t.F4, t.F5, t.F6, t.F7, t.F8, t.F9, value)
+	}
+}
+
 // MakeTuple10 is a function that converts its 10 parameters into a [Tuple10]
 func MakeTuple10[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10 any](t1 T1, t2 T2, t3 T3, t4 T4, t5 T5, t6 T6, t7 T7, t8 T8, t9 T9, t10 T10) Tuple10[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10] {
 	return Tuple10[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10]{t1, t2, t3, t4, t5, t6, t7, t8, t9, t10}

tuple/tuple.go

@@ -17,6 +17,10 @@
 // consider to use arrays for simplicity
 package tuple
 
+func Of[T1 any](t T1) Tuple1[T1] {
+	return MakeTuple1(t)
+}
+
 func First[T1, T2 any](t Tuple2[T1, T2]) T1 {
 	return t.F1
 }
@@ -29,7 +33,7 @@ func Swap[T1, T2 any](t Tuple2[T1, T2]) Tuple2[T2, T1] {
 	return MakeTuple2(t.F2, t.F1)
 }
 
-func Of[T1, T2 any](e T2) func(T1) Tuple2[T1, T2] {
+func Of2[T1, T2 any](e T2) func(T1) Tuple2[T1, T2] {
 	return func(t T1) Tuple2[T1, T2] {
 		return MakeTuple2(t, e)
 	}