Initial data commit

Task/Singleton/Wren/singleton.wren

@@ -0,0 +1,16 @@
+class Singleton {
+    // Returns the singleton. If it hasn't been created, creates it first.
+    static instance { __instance == null ? __instance = Singleton.new_() : __instance }
+
+    // Private constructor.
+    construct new_() {}
+
+    // instance method
+    speak() { System.print("I'm a singleton.") }
+
+}
+
+var s1 = Singleton.instance
+var s2 = Singleton.instance
+System.print("s1 and s2 are same object = %(Object.same(s1, s2))")
+s1.speak() // call instance method