Data update

Task/Singleton/Pluto/singleton-1.pluto

@@ -0,0 +1,19 @@
+-- Singleton.pluto --
+
+local instance = nil
+
+class singleton
+    static function getInstance()
+        if !instance then new singleton() end
+        return instance
+    end
+
+    function __construct()
+        assert(!instance, "The singleton instance already exists.")
+        instance = self
+    end
+
+    function print()
+        print("Hello, I'm a singleton.")
+    end
+end