Initial data commit

Task/Singleton/Forth/singleton.fth

@@ -0,0 +1,28 @@
+include FMS-SI.f
+
+\ A singleton is created by using normal Forth data
+\ allocation words such as value or variable as instance variables.
+\ Any number of instances of a singleton class may be
+\ instantiated but messages will all operate on the same shared data
+\ so it is the same as if only one object has been created.
+\ The data name space will remain private to the class.
+
+:class singleton
+  0 value a
+  0 value b
+  :m printa a . ;m
+  :m printb b . ;m
+  :m add-a ( n -- ) a + to a ;m
+  :m add-b ( n -- ) b + to b ;m
+;class
+
+singleton s1
+singleton s2
+singleton s3
+
+4 s1 add-a
+9 s2 add-b
+s3 printa \ => 4
+s3 printb \ => 9
+s1 printb \ => 9
+s2 printa \ => 4