Added iterators to sync2 package (#43)

* Added iterators to sync2 package

* Added missing license

* Fix version incompatibility

Author: applejag

go.work

@@ -0,0 +1,10 @@
+// SPDX-FileCopyrightText: 2025 Kalle Fagerberg
+//
+// SPDX-License-Identifier: CC0-1.0
+
+go 1.23
+
+use (
+	.
+	./sync2/internal/go_1_23
+)

go.work.sum

@@ -0,0 +1 @@
+gopkg.in/typ.v4 v4.3.1/go.mod h1:wolXe8DlewxRCjA7SOiT3zjrZ0eQJZcr8cmV6bQWJUM=

go.work.sum.license

@@ -0,0 +1,3 @@
+SPDX-FileCopyrightText: 2025 Kalle Fagerberg
+
+SPDX-License-Identifier: CC0-1.0

sync2/internal/go_1_23/go.mod

@@ -0,0 +1,9 @@
+// SPDX-FileCopyrightText: 2025 Kalle Fagerberg
+//
+// SPDX-License-Identifier: CC0-1.0
+
+module gopkg.in/typ.v4/internal/go_1_23
+
+go 1.23
+
+require gopkg.in/typ.v4 v4.3.1

sync2/internal/go_1_23/go.sum

@@ -0,0 +1,2 @@
+gopkg.in/typ.v4 v4.3.1 h1:z3vGwIIn2X8GjP589+YS8YWmpNqBFEy0w7OcGWj0NZ4=
+gopkg.in/typ.v4 v4.3.1/go.mod h1:wolXe8DlewxRCjA7SOiT3zjrZ0eQJZcr8cmV6bQWJUM=

sync2/internal/go_1_23/go.sum.license

@@ -0,0 +1,3 @@
+SPDX-FileCopyrightText: 2025 Kalle Fagerberg
+
+SPDX-License-Identifier: CC0-1.0

sync2/internal/go_1_23/map_iter_test.go

@@ -0,0 +1,30 @@
+// SPDX-FileCopyrightText: 2025 Kalle Fagerberg
+//
+// SPDX-License-Identifier: MIT
+
+package go123_test
+
+import (
+	"maps"
+	"testing"
+
+	"gopkg.in/typ.v4/sync2"
+)
+
+func TestMapIterCompiles(t *testing.T) {
+	m := new(sync2.Map[int, string])
+
+	for range sync2.MapAll(m) {
+		// do nothing
+	}
+	for range sync2.MapKeys(m) {
+		// do nothing
+	}
+	for range sync2.MapValues(m) {
+		// do nothing
+	}
+
+	otherMap := map[int]string{}
+	sync2.MapInsert(m, maps.All(otherMap))
+	_ = sync2.MapCollect(maps.All(otherMap))
+}

sync2/map_example_test.go

@@ -0,0 +1,46 @@
+// SPDX-FileCopyrightText: 2025 Kalle Fagerberg
+//
+// SPDX-License-Identifier: MIT
+
+package sync2_test
+
+import (
+	"fmt"
+
+	"gopkg.in/typ.v4/sync2"
+)
+
+func ExampleMap() {
+	m := new(sync2.Map[int, string])
+	m.Store(1, "one")
+	m.Store(2, "two")
+	m.Store(3, "three")
+
+	fmt.Println("Len:", m.Len())
+
+	// Output:
+	// Len: 3
+}
+
+func ExampleMap_Load() {
+	m := new(sync2.Map[int, string])
+	m.Store(1, "one")
+	m.Store(2, "two")
+	m.Store(3, "three")
+
+	if value, ok := m.Load(0); ok {
+		fmt.Println("Map[0]:", value)
+	} else {
+		fmt.Println("Map[0]: (no value)")
+	}
+
+	if value, ok := m.Load(1); ok {
+		fmt.Println("Map[1]:", value)
+	} else {
+		fmt.Println("Map[1]: (no value)")
+	}
+
+	// Output:
+	// Map[0]: (no value)
+	// Map[1]: one
+}

sync2/map_iter.go

@@ -0,0 +1,58 @@
+// SPDX-FileCopyrightText: 2025 Kalle Fagerberg
+//
+// SPDX-License-Identifier: MIT
+
+package sync2
+
+// MapAll returns an iterator over key-value pairs in m.
+// The iteeration order is not specified and is not guaranteed to be the same
+// from one call to the next.
+func MapAll[K comparable, V any](m *Map[K, V]) func(yield func(K, V) bool) {
+	return func(yield func(K, V) bool) {
+		m.Range(func(key K, value V) bool {
+			return yield(key, value)
+		})
+	}
+}
+
+// MapKeys returns an iterator over keys in m.
+// The iteeration order is not specified and is not guaranteed to be the same
+// from one call to the next.
+func MapKeys[K comparable, V any](m *Map[K, V]) func(yield func(K) bool) {
+	return func(yield func(K) bool) {
+		m.Range(func(key K, _ V) bool {
+			return yield(key)
+		})
+	}
+}
+
+// MapValues returns an iterator over values in m.
+// The iteeration order is not specified and is not guaranteed to be the same
+// from one call to the next.
+func MapValues[K comparable, V any](m *Map[K, V]) func(yield func(V) bool) {
+	return func(yield func(V) bool) {
+		m.Range(func(_ K, value V) bool {
+			return yield(value)
+		})
+	}
+}
+
+// MapInsert adds the key-value pairs from seq to m.
+// If a key in seq already exists in m, its value will be overwritten.
+func MapInsert[K comparable, V any](m *Map[K, V], iter func(yield func(K, V) bool)) {
+	iter(func(k K, v V) bool {
+		m.Store(k, v)
+		return true
+	})
+}
+
+// MapCollect collects key-value pairs from seq into a new map
+// and returns it.
+func MapCollect[K comparable, V any](iter func(yield func(K, V) bool)) *Map[K, V] {
+	m := new(Map[K, V])
+	iter(func(k K, v V) bool {
+		m.Store(k, v)
+		return true
+	})
+	return m
+}

sync2/map_iter_example_test.go

@@ -0,0 +1,53 @@
+// SPDX-FileCopyrightText: 2025 Kalle Fagerberg
+//
+// SPDX-License-Identifier: MIT
+
+package sync2_test
+
+import (
+	"gopkg.in/typ.v4/sync2"
+)
+
+func ExampleMapAll() {
+	m := new(sync2.Map[int, string])
+	m.Store(1, "one")
+	m.Store(2, "two")
+
+	// In Go 1.23+ you can iterate the values like so:
+	/*
+		for k, v := range sync2.MapAll(m) {
+			fmt.Printf("%s: %q\n", k, v)
+		}
+	*/
+}
+
+func ExampleMapKeys() {
+	m := new(sync2.Map[int, string])
+	m.Store(1, "one")
+	m.Store(2, "two")
+
+	// In Go 1.23+ you can iterate the values like so:
+	/*
+		for k := range sync2.MapKeys(m) {
+			fmt.Printf("key: %s\n", k)
+		}
+	*/
+}
+
+func ExampleMapValues() {
+	m := new(sync2.Map[int, string])
+	m.Store(1, "one")
+	m.Store(2, "two")
+
+	// In Go 1.23+ you can iterate the values like so:
+	/*
+		for k := range sync2.MapValues(m) {
+			fmt.Printf("value: %q\n", v)
+		}
+	*/
+
+	// Alternatively you can get a slice of keys like so:
+	/*
+		keys := slices.Collect(sync2.MapValues(m))
+	*/
+}