Initial data commit

Task/Singleton/Vala/singleton.vala

@@ -0,0 +1,24 @@
+public class Singleton : Object {
+    static Singleton? instance;
+
+    // Private constructor
+    Singleton() {
+
+    }
+
+    // Public constructor
+    public static Singleton get_instance() {
+        if (instance == null) {
+            instance = new Singleton();
+        }
+        return instance;
+    }
+}
+
+void main() {
+    Singleton a = Singleton.get_instance();
+    Singleton b = Singleton.get_instance();
+    if (a == b) {
+        print("Equal.\n");
+    }
+}