Singleton added

code/singleton.php

@@ -0,0 +1,48 @@
+<?php
+
+/**
+ * @package: patterns
+ * @author: Yevhen Odynets
+ * @date: 2025-07-03
+ * @time: 08:39
+ */
+
+declare(strict_types = 1);
+
+use Pattern\Creational\{Singleton, Sub\Single};
+
+/**
+ * The client code.
+ *
+ * @noinspection ForgottenDebugOutputInspection
+ */
+function clientCode(): void
+{
+    $output = [
+        'where' => trace(),
+        's1' => Singleton::getInstance('s1'),
+        's2' => Singleton::getInstance('s2'),
+    ];
+
+    if ($output['s1'] === $output['s2']) {
+        $output['message'] = "Singleton works, both variables contain the same instance.";
+    } else {
+        $output['message'] = "Singleton failed, variables contain different instances.";
+    }
+
+    $output['s1']->setValue('value set from s1@Singleton::class');
+    dump($output['s1']->getValue());
+    $output['s2']->setValue('value set from s2@Singleton::class');
+    dump($output, $output['s1']->getValue(), $output['s2']->getValue());
+}
+
+clientCode();
+
+$single = Single::getInstance('from subclass');
+$single->setValue('value set from Single::class')->childish();
+
+
+$singleton = Singleton::getInstance('from Singleton');
+
+/** @noinspection ForgottenDebugOutputInspection */
+dump($single->getValue(), $singleton->getValue());