tasks a-s

Task/Polymorphic-copy/BBC-BASIC/polymorphic-copy.bbc

@@ -0,0 +1,28 @@
+      INSTALL @lib$ + "CLASSLIB"
+
+      REM Create parent class T:
+      DIM classT{array#(0), setval, retval}
+      DEF classT.setval (n%,v) classT.array#(n%) = v : ENDPROC
+      DEF classT.retval (n%) = classT.array#(n%)
+      PROC_class(classT{})
+
+      REM Create class S derived from T, known only at run-time:
+      RunTimeSize% = RND(100)
+      DIM classS{array#(RunTimeSize%)}
+      PROC_inherit(classS{}, classT{})
+      DEF classS.retval (n%) = classS.array#(n%) ^ 2 : REM Overridden method
+      PROC_class(classS{})
+
+      REM Create an instance of class S:
+      PROC_new(myobject{}, classS{})
+
+      REM Now make a copy of the instance:
+      DIM mycopy{} = myobject{}
+      mycopy{} = myobject{}
+      PROC_discard(myobject{})
+
+      REM Test the copy (should print 123^2):
+      PROC(mycopy.setval)(RunTimeSize%, 123)
+      result% = FN(mycopy.retval)(RunTimeSize%)
+      PRINT result%
+      END