added null methods on propertytrait

Author: transistive

src/Traits/PropertyTypeTrait.php

@@ -24,6 +24,8 @@
 use WikibaseSolutions\CypherDSL\Equality;
 use WikibaseSolutions\CypherDSL\In;
 use WikibaseSolutions\CypherDSL\Inequality;
+use WikibaseSolutions\CypherDSL\IsNotNull;
+use WikibaseSolutions\CypherDSL\IsNull;
 use WikibaseSolutions\CypherDSL\Types\CompositeTypes\ListType;
 use WikibaseSolutions\CypherDSL\Types\PropertyTypes\PropertyType;
 
@@ -70,4 +72,20 @@ public function in(ListType $right, bool $insertParentheses = true): In
     {
         return new In($this, $right, $insertParentheses);
     }
+
+    /**
+     * @inheritDoc
+     */
+    public function isNull(): IsNull
+    {
+        return new IsNull($this);
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function isNotNull(): IsNotNull
+    {
+        return new IsNotNull($this);
+    }
 }

src/Types/PropertyTypes/PropertyType.php

@@ -5,6 +5,8 @@
 use WikibaseSolutions\CypherDSL\Equality;
 use WikibaseSolutions\CypherDSL\In;
 use WikibaseSolutions\CypherDSL\Inequality;
+use WikibaseSolutions\CypherDSL\IsNotNull;
+use WikibaseSolutions\CypherDSL\IsNull;
 use WikibaseSolutions\CypherDSL\Types\AnyType;
 use WikibaseSolutions\CypherDSL\Types\CompositeTypes\ListType;
 
@@ -57,4 +59,18 @@ public function notEquals(PropertyType $right): Inequality;
      * @return In
      */
     public function in(ListType $right): In;
+
+    /**
+     * Checks whether the element is null.
+     *
+     * @return IsNull
+     */
+    public function isNull(): IsNull;
+
+    /**
+     * Checks whether the element is not null.
+     *
+     * @return IsNotNull
+     */
+    public function isNotNull(): IsNotNull;
 }