builtin: add map.values() (#14301)

vlib/builtin/map_test.v

@@ -47,6 +47,16 @@ fn test_keys_many() {
 	assert keys == strings
 }
 
+fn test_values_many() {
+	mut m := map[string]int{}
+	for i, s in strings {
+		m[s] = i
+	}
+	values := m.values()
+	assert values.len == strings.len
+	assert values.len == m.len
+}
+
 fn test_deletes_many() {
 	mut m := map[string]int{}
 	for i, s in strings {
@@ -59,6 +69,7 @@ fn test_deletes_many() {
 	}
 	assert m.len == 0
 	assert m.keys().len == 0
+	assert m.values().len == 0
 }
 
 struct User {
@@ -103,6 +114,13 @@ fn test_map() {
 	assert m['hi'] == 0
 	assert m.keys().len == 1
 	assert m.keys()[0] == 'hello'
+	// Test `.values()`
+	values := m.values()
+	assert values.len == 1
+	assert 80 !in values
+	assert 101 in values
+	assert m.values().len == 1
+	assert m.values()[0] == 101
 	// //
 	mut users := map[string]User{}
 	users['1'] = User{'Peter'}
@@ -580,6 +598,7 @@ fn test_int_keys() {
 		4: 16
 		5: 25
 	}
+	assert m2.values() == [9, 16, 25]
 
 	assert m2.len == 3
 	// clone
@@ -636,6 +655,16 @@ fn test_voidptr_keys() {
 	assert m.len == 2
 }
 
+fn test_voidptr_values() {
+	mut m := map[string]voidptr{}
+	v := 5
+	m['var'] = &v
+	m['map'] = &m
+	assert m['var'] == &v
+	assert m['map'] == &m
+	assert m.values().len == 2
+}
+
 fn test_rune_keys() {
 	mut m := {
 		`!`: 2