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

Task/Singleton/Pluto/singleton-2.pluto

@@ -0,0 +1,12 @@
+-- Singleton_user.pluto --
+
+require "Singleton"
+
+local s = singleton.getInstance()
+s:print()
+local t = singleton.getInstance()
+t:print()
+print(s == t)              -- true, as same object
+print(instance)            -- nil
+local u = new singleton()  -- throws an error
+u:print()                  -- not executed