map and mapSelf : support $process with only one parameter

+ Simplify/Correct template declarations
+ Fix method signatures (self → static)

composer.json

@@ -2,10 +2,20 @@
     "name":              "jrosset/collections",
     "description":       "Classes for collections",
     "keywords":          [ ],
+    "type":              "library",
+
+    "config":            {
+        "sort-packages": true
+    },
+    "extra":             {
+        "branch-alias": {
+            "dev-master": "3.x-dev"
+        }
+    },
 
     "minimum-stability": "stable",
     "require":           {
-        "php": "^7.4 || ^8.0"
+        "php": "^8.1"
     },
     "autoload":          {
         "psr-4":                 {
@@ -30,4 +40,4 @@
         "docs":   "https://git.jrosset.ovh/jrosset/PhpCollections/wiki",
         "source": "https://git.jrosset.ovh/jrosset/PhpCollections"
     }
-}
+}

src/Collections/Collection.php

@@ -17,40 +17,40 @@ class Collection extends ImmutableCollection implements ICollection {
     /**
      * @inheritDoc
      */
-    public function set ($key, $value) {
+    public function set ($key, $value): static {
         return $this->_set($key, $value);
     }
     /**
      * @inheritDoc
      */
-    public function merge (IImmutableCollection ...$collections) {
+    public function merge (IImmutableCollection ...$collections): static {
         return $this->_merge(...$collections);
     }
 
     /**
      * @inheritDoc
      */
-    public function add (...$values) {
+    public function add (...$values): static {
         return $this->_add(...$values);
     }
     /**
      * @inheritDoc
      */
-    public function addCollection (IImmutableCollection ...$collections) {
+    public function addCollection (IImmutableCollection ...$collections): static {
         return $this->_addCollection(...$collections);
     }
 
     /**
      * @inheritDoc
      */
-    public function prepend (...$values) {
+    public function prepend (...$values): static {
         array_unshift($this->elements, ...$values);
         return $this;
     }
     /**
      * @inheritDoc
      */
-    public function prependCollection (IImmutableCollection ...$collections) {
+    public function prependCollection (IImmutableCollection ...$collections): static {
         $prepend = array_merge(
             ...array_map(
                    function (IImmutableCollection $collection): array {
@@ -65,21 +65,21 @@ class Collection extends ImmutableCollection implements ICollection {
     /**
      * @inheritDoc
      */
-    public function clear () {
+    public function clear (): static {
         $this->_initialize();
         return $this;
     }
     /**
      * @inheritDoc
      */
-    public function remove ($key) {
+    public function remove ($key): static {
         unset($this->elements[$this->_normalizeKey($key)]);
         return $this;
     }
     /**
      * @inheritDoc
      */
-    public function removeValue ($value, bool $strict = false) {
+    public function removeValue ($value, bool $strict = false): static {
         foreach ($this->elements as $currentKey => $currentValue) {
             if (($strict && $value === $currentValue) || (!$strict && $value == $currentValue)) {
                 unset($this->elements[$currentKey]);
@@ -112,37 +112,41 @@ class Collection extends ImmutableCollection implements ICollection {
     /**
      * @inheritDoc
      */
-    public function offsetSet ($offset, $value): void {
+    public function offsetSet (mixed $offset, mixed $value): void {
         $this->set($offset, $value);
     }
     /**
      * @inheritDoc
      */
-    public function offsetUnset ($offset): void {
+    public function offsetUnset (mixed $offset): void {
         $this->remove($offset);
     }
 
     /**
      * @inheritDoc
      */
-    public function sliceSelf (int $offset, ?int $length = null) {
-        $this->_checkOffset($offset);
-
-        $this->elements = array_slice($this->elements, $offset, $length, true);
+    public function sliceSelf (int $offset, ?int $length = null): static {
+        if ($this->count() === 0) {
+            $this->elements = [];
+        }
+        else {
+            $this->_checkOffset($offset);
+            $this->elements = array_slice($this->elements, $offset, $length, true);
+        }
         return $this;
     }
 
     /**
      * @inheritDoc
      */
-    public function filterSelf (Closure $filter) {
+    public function filterSelf (Closure $filter): static {
         $this->elements = array_filter($this->elements, $filter);
         return $this;
     }
     /**
      * @inheritDoc
      */
-    public function removeEmpties () {
+    public function removeEmpties (): static {
         return $this->filterSelf(function ($value) {
             return empty($value);
         });
@@ -150,22 +154,22 @@ class Collection extends ImmutableCollection implements ICollection {
     /**
      * @inheritDoc
      */
-    public function mapSelf (Closure $process) {
-        $this->elements = array_map($process, $this->elements);
+    public function mapSelf (Closure $process): static {
+        $this->elements = $this->map($process)->elements;
         return $this;
     }
 
     /**
      * @inheritDoc
      */
-    public function sortSelf ($sorter = null) {
+    public function sortSelf (Closure|IComparator|null $sorter = null): static {
         uasort($this->elements, self::_normalizeSorter($sorter));
         return $this;
     }
     /**
      * @inheritDoc
      */
-    public function sortSelfByKey ($sorter) {
+    public function sortSelfByKey (Closure|IComparator $sorter): static {
         uksort($this->elements, self::_normalizeSorter($sorter));
         return $this;
     }

src/Collections/ICollection.php

@@ -3,8 +3,8 @@
 namespace jrosset\Collections;
 
 use Closure;
-use Exception;
 use OutOfBoundsException;
+use Throwable;
 
 /**
  * Interface for a collection
@@ -22,20 +22,16 @@ interface ICollection extends IImmutableCollection {
      * @param TValue $value The value
      *
      * @return $this
-     *
-     * @noinspection PhpMissingReturnTypeInspection
      */
-    public function set ($key, $value);
+    public function set ($key, $value): static;
     /**
      * Merge one or multiple collections into the current one
      *
      * @param IImmutableCollection<TKey, TValue> ...$collections The collections to merge
      *
      * @return $this
-     *
-     * @noinspection PhpMissingReturnTypeInspection
      */
-    public function merge (IImmutableCollection ...$collections);
+    public function merge (IImmutableCollection ...$collections): static;
 
     /**
      * Add one or multiple values
@@ -43,20 +39,16 @@ interface ICollection extends IImmutableCollection {
      * @param TValue ...$values The values
      *
      * @return $this
-     *
-     * @noinspection PhpMissingReturnTypeInspection
      */
-    public function add (...$values);
+    public function add (...$values): static;
     /**
      * Add the <b>values</b> of one or multiple collections
      *
      * @param IImmutableCollection<TKey, TValue> ...$collections The collections to add
      *
      * @return $this
-     *
-     * @noinspection PhpMissingReturnTypeInspection
      */
-    public function addCollection (IImmutableCollection ...$collections);
+    public function addCollection (IImmutableCollection ...$collections): static;
 
     /**
      * Add one or multiple values at the beginning of the current collection
@@ -64,39 +56,31 @@ interface ICollection extends IImmutableCollection {
      * @param TValue ...$values The values
      *
      * @return $this
-     *
-     * @noinspection PhpMissingReturnTypeInspection
      */
-    public function prepend (...$values);
+    public function prepend (...$values): static;
     /**
      * Add the <b>values</b> of one or multiple collections at the beginning of the current collection
      *
      * @param IImmutableCollection<TKey, TValue> ...$collections The collections to add
      *
      * @return $this
-     *
-     * @noinspection PhpMissingReturnTypeInspection
      */
-    public function prependCollection (IImmutableCollection ...$collections);
+    public function prependCollection (IImmutableCollection ...$collections): static;
 
     /**
      * Empty the collection
      *
      * @return $this
-     *
-     * @noinspection PhpMissingReturnTypeInspection
      */
-    public function clear ();
+    public function clear (): static;
     /**
      * Remove a value from it's key
      *
      * @param TKey $key The key
      *
      * @return $this
-     *
-     * @noinspection PhpMissingReturnTypeInspection
      */
-    public function remove ($key);
+    public function remove ($key): static;
     /**
      * Delete all instances of a value
      *
@@ -104,10 +88,8 @@ interface ICollection extends IImmutableCollection {
      * @param bool   $strict Strict comparison ?
      *
      * @return $this
-     *
-     * @noinspection PhpMissingReturnTypeInspection
      */
-    public function removeValue ($value, bool $strict = false);
+    public function removeValue ($value, bool $strict = false): static;
 
     /**
      * Get and remove the first element
@@ -137,10 +119,8 @@ interface ICollection extends IImmutableCollection {
      * @return $this
      *
      * @throws OutOfBoundsException If the offset is not valid
-     *
-     * @noinspection PhpMissingReturnTypeInspection
      */
-    public function sliceSelf (int $offset, ?int $length = null);
+    public function sliceSelf (int $offset, ?int $length = null): static;
 
     /**
      * Keep only elements that satisfy predicate $filter
@@ -148,30 +128,24 @@ interface ICollection extends IImmutableCollection {
      * @param Closure(TKey, TValue):bool $filter The filtering predicate
      *
      * @return $this
-     *
-     * @noinspection PhpMissingReturnTypeInspection
      */
-    public function filterSelf (Closure $filter);
+    public function filterSelf (Closure $filter): static;
     /**
      * Keep only non-empty elements
      *
      * Use {@see https://www.php.net/manual/function.empty.php empty} to check if element is empty or not
      *
      * @return $this
-     *
-     * @noinspection PhpMissingReturnTypeInspection
      */
-    public function removeEmpties ();
+    public function removeEmpties (): static;
     /**
      * Applied <b>$process</b> on all elements
      *
      * @param Closure(TKey, TValue): TValue $process The process function to apply on each element
      *
      * @return $this
-     *
-     * @noinspection PhpMissingReturnTypeInspection
      */
-    public function mapSelf (Closure $process);
+    public function mapSelf (Closure $process): static;
 
     /**
      * Sort the elements (by value)
@@ -184,11 +158,9 @@ interface ICollection extends IImmutableCollection {
      *
      * @return $this
      *
-     * @throws Exception If an error occurs
-     *
-     * @noinspection PhpMissingReturnTypeInspection
+     * @throws Throwable If an error occurs
      */
-    public function sortSelf ($sorter = null);
+    public function sortSelf (Closure|IComparator|null $sorter = null): static;
     /**
      * Sort the elements by key
      *
@@ -199,9 +171,7 @@ interface ICollection extends IImmutableCollection {
      *
      * @return $this
      *
-     * @throws Exception If an error occurs
-     *
-     * @noinspection PhpMissingReturnTypeInspection
+     * @throws Throwable If an error occurs
      */
-    public function sortSelfByKey ($sorter);
+    public function sortSelfByKey (Closure|IComparator $sorter): static;
 }

src/Collections/IImmutableCollection.php

@@ -8,7 +8,6 @@ use Countable;
 use IteratorAggregate;
 use JsonSerializable;
 use OutOfBoundsException;
-use Serializable;
 use Throwable;
 
 /**
@@ -21,7 +20,7 @@ use Throwable;
  * @implements ArrayAccess<TKey, TValue>
  * @implements IArrayCast<TKey, TValue>
  */
-interface IImmutableCollection extends IteratorAggregate, JsonSerializable, Serializable, Countable, ArrayAccess, IArrayCast {
+interface IImmutableCollection extends IteratorAggregate, JsonSerializable, Countable, ArrayAccess, IArrayCast {
     /**
      * Checks if the collection is empty
      *
@@ -131,10 +130,8 @@ interface IImmutableCollection extends IteratorAggregate, JsonSerializable, Seri
      * @return static<TKey, TValue> The result collection
      *
      * @throws OutOfBoundsException If the offset is not valid
-     *
-     * @noinspection PhpMissingReturnTypeInspection
      */
-    public function slice (int $offset, ?int $length = null);
+    public function slice (int $offset, ?int $length = null): static;
 
     /**
      * Get a collection of all elements that satisfy predicate $filter
@@ -142,20 +139,16 @@ interface IImmutableCollection extends IteratorAggregate, JsonSerializable, Seri
      * @param Closure(TKey, TValue):bool $filter The filtering predicate
      *
      * @return static<TKey, TValue> The result collection
-     *
-     * @noinspection PhpMissingReturnTypeInspection
      */
-    public function filter (Closure $filter);
+    public function filter (Closure $filter): static;
     /**
      * Get a collection of all not empty elements
      *
      * Use {@see https://www.php.net/manual/function.empty.php empty} to check if element is empty or not
      *
      * @return static<TKey, TValue> The result collection
-     *
-     * @noinspection PhpMissingReturnTypeInspection
      */
-    public function withoutEmpties ();
+    public function withoutEmpties (): static;
     /**
      * A new collection with <b>$process</b> applied on all elements
      *
@@ -164,10 +157,8 @@ interface IImmutableCollection extends IteratorAggregate, JsonSerializable, Seri
      * @param Closure(TKey, TValue): TResultValue $process The process function to apply on each element
      *
      * @return static<TKey, TResultValue> The result collection
-     *
-     * @noinspection PhpMissingReturnTypeInspection
      */
-    public function map (Closure $process);
+    public function map (Closure $process): static;
 
     /**
      * Get a collection with the elements sorted (by value)
@@ -181,10 +172,8 @@ interface IImmutableCollection extends IteratorAggregate, JsonSerializable, Seri
      * @return static<TKey, TValue> The result collection
      *
      * @throws Throwable If an error occurs
-     *
-     * @noinspection PhpMissingReturnTypeInspection
      */
-    public function sort ($sorter = null);
+    public function sort (Closure|IComparator|null $sorter = null): static;
     /**
      * Get a collection with the elements sorted by key
      *
@@ -196,10 +185,8 @@ interface IImmutableCollection extends IteratorAggregate, JsonSerializable, Seri
      * @return static<TKey, TValue> The result collection
      *
      * @throws Throwable If an error occurs
-     *
-     * @noinspection PhpMissingReturnTypeInspection
      */
-    public function sortByKey ($sorter);
+    public function sortByKey (Closure|IComparator $sorter): static;
 
     /**
      * The list of all keys
@@ -211,10 +198,8 @@ interface IImmutableCollection extends IteratorAggregate, JsonSerializable, Seri
      * The list of all values
      *
      * @return static<int, TValue> The list of all values
-     *
-     * @noinspection PhpMissingReturnTypeInspection
      */
-    public function values ();
+    public function values (): static;
 
     /**
      * Join all values with a separator
@@ -231,10 +216,8 @@ interface IImmutableCollection extends IteratorAggregate, JsonSerializable, Seri
      * @param string $separator The split separator
      *
      * @return static<int, string> The result collection
-     *
-     * @noinspection PhpMissingReturnTypeInspection
      */
-    public static function split (string $value, string $separator);
+    public static function split (string $value, string $separator): static;
 
     /**
      * Create a collection filled with the same element
@@ -243,10 +226,8 @@ interface IImmutableCollection extends IteratorAggregate, JsonSerializable, Seri
      * @param TValue $value The value to fill the collection
      *
      * @return static<int, TValue> The result collection
-     *
-     * @noinspection PhpMissingReturnTypeInspection
      */
-    public static function fill (int $size, $value);
+    public static function fill (int $size, $value): static;
     /**
      * Create a collection filled with the same element, using a list of keys
      *
@@ -254,10 +235,8 @@ interface IImmutableCollection extends IteratorAggregate, JsonSerializable, Seri
      * @param TValue                     $value The value to fill the collection
      *
      * @return static<TKey, TValue> The result collection
-     *
-     * @noinspection PhpMissingReturnTypeInspection
      */
-    public static function fillWithKeys (IImmutableCollection $keys, $value);
+    public static function fillWithKeys (IImmutableCollection $keys, $value): static;
 
     /**
      * Merge the current collection with one or multiple collections
@@ -265,8 +244,6 @@ interface IImmutableCollection extends IteratorAggregate, JsonSerializable, Seri
      * @param IImmutableCollection<TKey, TValue> ...$collections The other collections to merge
      *
      * @return static<TKey, TValue> The result collection
-     *
-     * @noinspection PhpMissingReturnTypeInspection
      */
-    public function mergeWith (IImmutableCollection ...$collections);
+    public function mergeWith (IImmutableCollection ...$collections): static;
 }

src/Collections/ImmutableCollection.php

@@ -6,6 +6,7 @@ use ArrayIterator;
 use Closure;
 use InvalidArgumentException;
 use OutOfBoundsException;
+use ReflectionFunction;
 use Traversable;
 
 /**
@@ -63,10 +64,8 @@ class ImmutableCollection implements IImmutableCollection {
      * @return $this
      *
      * @internal
-     *
-     * @noinspection PhpMissingReturnTypeInspection
      */
-    protected function _set ($key, $value) {
+    protected function _set ($key, $value): static {
         $this->elements[$this->_normalizeKey($key)] = $value;
         return $this;
     }
@@ -78,10 +77,8 @@ class ImmutableCollection implements IImmutableCollection {
      * @return $this
      *
      * @internal
-     *
-     * @noinspection PhpMissingReturnTypeInspection
      */
-    protected function _merge (IImmutableCollection ...$collections) {
+    protected function _merge (IImmutableCollection ...$collections): static {
         foreach ($collections as $collection) {
             foreach ($collection as $key => $value) {
                 $this->_set($key, $value);
@@ -97,10 +94,8 @@ class ImmutableCollection implements IImmutableCollection {
      * @return $this
      *
      * @internal
-     *
-     * @noinspection PhpMissingReturnTypeInspection
      */
-    protected function _add (...$values) {
+    protected function _add (...$values): static {
         foreach ($values as $value) {
             $this->elements[] = $value;
         }
@@ -112,10 +107,8 @@ class ImmutableCollection implements IImmutableCollection {
      * @param IImmutableCollection ...$collections The collections to add
      *
      * @return $this
-     *
-     * @noinspection PhpMissingReturnTypeInspection
      */
-    protected function _addCollection (IImmutableCollection ...$collections) {
+    protected function _addCollection (IImmutableCollection ...$collections): static {
         foreach ($collections as $collection) {
             foreach ($collection as $value) {
                 $this->_add($value);
@@ -158,25 +151,25 @@ class ImmutableCollection implements IImmutableCollection {
     /**
      * @inheritDoc
      */
-    public function offsetExists ($offset): bool {
+    public function offsetExists (mixed $offset): bool {
         return $this->exists($offset);
     }
     /**
      * @inheritDoc
      */
-    public function offsetGet ($offset) {
+    public function offsetGet (mixed $offset): mixed {
         return $this->get($offset);
     }
     /**
      * @inheritDoc
      */
-    public function offsetSet ($offset, $value): void {
+    public function offsetSet (mixed $offset, mixed $value): void {
         throw new ImmutableException();
     }
     /**
      * @inheritDoc
      */
-    public function offsetUnset ($offset): void {
+    public function offsetUnset (mixed $offset): void {
         throw new ImmutableException();
     }
 
@@ -191,16 +184,14 @@ class ImmutableCollection implements IImmutableCollection {
         ];
     }
     /**
-     * @inheritDoc
-     */
-    public function serialize (): ?string {
-        return serialize($this->elements);
-    }
-    /**
-     * @inheritDoc
+     * {@see https://www.php.net/manual/function.unserialize.php Unserialize} from the list of serialized properties
+     *
+     * @param array $data The list of serialized properties
+     *
+     * @return void
      */
-    public function unserialize ($data) {
-        $this->_initialize(unserialize($data));
+    public function __unserialize (array $data): void {
+        $this->_initialize($data['elements']);
     }
 
     /**
@@ -239,7 +230,7 @@ class ImmutableCollection implements IImmutableCollection {
     /**
      * @inheritDoc
      */
-    public function get ($key) {
+    public function get ($key): mixed {
         return $this->elements[$this->_normalizeKey($key)] ?? null;
     }
     /**
@@ -298,10 +289,13 @@ class ImmutableCollection implements IImmutableCollection {
     /**
      * @inheritDoc
      */
-    public function slice (int $offset, ?int $length = null) {
-        $this->_checkOffset($offset);
-
+    public function slice (int $offset, ?int $length = null): static {
         $output = new static();
+        if ($this->count() === 0) {
+            return $output;
+        }
+
+        $this->_checkOffset($offset);
 
         $currentIndex = 0;
         foreach ($this->elements as $key => $value) {
@@ -321,7 +315,7 @@ class ImmutableCollection implements IImmutableCollection {
     /**
      * @inheritDoc
      */
-    public function filter (Closure $filter) {
+    public function filter (Closure $filter): static {
         $output = new static();
         foreach ($this->elements as $key => $value) {
             if (!$filter($key, $value)) {
@@ -334,7 +328,7 @@ class ImmutableCollection implements IImmutableCollection {
     /**
      * @inheritDoc
      */
-    public function withoutEmpties () {
+    public function withoutEmpties (): static {
         return $this->filter(function ($value) {
             return empty($value);
         });
@@ -342,10 +336,21 @@ class ImmutableCollection implements IImmutableCollection {
     /**
      * @inheritDoc
      */
-    public function map (Closure $process) {
+    public function map (Closure $process): static {
+        //region Regarde si $process doit être appelée avec la clé en plus de la valeur
+        $callProcessWithKey = false;
+        /** @noinspection PhpUnhandledExceptionInspection */
+        $processReflection = new ReflectionFunction($process);
+        if (count($processReflection->getParameters()) >= 2) {
+            if (!$processReflection->getParameters()[1]->isDefaultValueAvailable()) {
+                $callProcessWithKey = true;
+            }
+        }
+        //endregion
+
         $output = new static();
         foreach ($this->elements as $key => $value) {
-            $output->_set($key, $process($key, $value));
+            $output->_set($key, $callProcessWithKey ? $process($key, $value) : $process($value));
         }
         return $output;
     }
@@ -353,7 +358,7 @@ class ImmutableCollection implements IImmutableCollection {
     /**
      * @inheritDoc
      */
-    public function sort ($sorter = null) {
+    public function sort (Closure|IComparator|null $sorter = null): static {
         $elements = $this->toArray();
         uasort($elements, self::_normalizeSorter($sorter));
 
@@ -362,7 +367,7 @@ class ImmutableCollection implements IImmutableCollection {
     /**
      * @inheritDoc
      */
-    public function sortByKey ($sorter) {
+    public function sortByKey (Closure|IComparator $sorter): static {
         $elements = $this->toArray();
         uksort($elements, self::_normalizeSorter($sorter));
 
@@ -384,7 +389,7 @@ class ImmutableCollection implements IImmutableCollection {
      *                                     <br>= 0 if value1 equals value2
      *                                     <br>&gt; 0 if value1 is after value2
      */
-    public static function _normalizeSorter ($sorter): Closure {
+    public static function _normalizeSorter (Closure|IComparator|null $sorter): Closure {
         if ($sorter === null) {
             return function (IComparable $value1, IComparable $value2): int {
                 return $value1->compareTo($value2);
@@ -409,14 +414,14 @@ class ImmutableCollection implements IImmutableCollection {
     /**
      * @inheritDoc
      */
-    public function values () {
+    public function values (): static {
         return new static(array_values($this->elements));
     }
 
     /**
      * @inheritDoc
      */
-    public function jsonSerialize () {
+    public function jsonSerialize (): mixed {
         return $this->elements;
     }
 
@@ -429,14 +434,14 @@ class ImmutableCollection implements IImmutableCollection {
     /**
      * @inheritDoc
      */
-    public static function split (string $value, string $separator) {
+    public static function split (string $value, string $separator): static {
         return new static (explode($separator, $value));
     }
 
     /**
      * @inheritDoc
      */
-    public static function fill (int $size, $value) {
+    public static function fill (int $size, $value): static {
         $keys = new ImmutableCollection();
         for ($curr = 0; $curr < $size; $curr++) {
             $keys->_add($curr);
@@ -447,7 +452,7 @@ class ImmutableCollection implements IImmutableCollection {
     /**
      * @inheritDoc
      */
-    public static function fillWithKeys (IImmutableCollection $keys, $value) {
+    public static function fillWithKeys (IImmutableCollection $keys, $value): static {
         $collection = new static();
         foreach ($keys as $key) {
             $collection->_set($key, $value);
@@ -458,7 +463,7 @@ class ImmutableCollection implements IImmutableCollection {
     /**
      * @inheritDoc
      */
-    public function mergeWith (IImmutableCollection ...$collections) {
+    public function mergeWith (IImmutableCollection ...$collections): static {
         return (clone $this)->_merge(...$collections);
     }
 }

src/Collections/TInsensitiveCaseKey.php

@@ -7,11 +7,9 @@ namespace jrosset\Collections;
  */
 trait TInsensitiveCaseKey {
     /**
-     * Normalize a key
+     * @inheritDoc
      *
-     * @param array-key $key The key to normalize
-     *
-     * @return array-key The normalized key
+     * @noinspection PhpMissingReturnTypeInspection
      */
     protected function _normalizeKey ($key) {
         return mb_strtolower($key);

src/Collections/TUniqueValues.php

@@ -12,7 +12,7 @@ trait TUniqueValues {
     /**
      * @inheritDoc
      */
-    protected function _set ($key, $value): self {
+    protected function _set ($key, $value): static {
         if ($this->contains($value)) {
             return $this;
         }
@@ -23,7 +23,7 @@ trait TUniqueValues {
     /**
      * @inheritDoc
      */
-    protected function _add (...$values): self {
+    protected function _add (...$values): static {
         foreach ($values as $value) {
             if ($this->contains($value)) {
                 continue;