Initial data commit

Task/Delegates/Forth/delegates.fth

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+include FMS-SI.f
+
+:class delegate
+  :m thing ." delegate implementation" ;m
+;class
+
+delegate slave
+
+:class delegator
+  ivar del  \ object container
+  :m !: ( n -- ) del ! ;m
+  :m init: 0 del ! ;m
+  :m default ." default implementation" ;m
+  :m operation
+     del @ 0= if self default exit then
+     del @ has-meth thing
+     if del @ thing
+     else self default
+     then ;m
+;class
+
+delegator master
+
+\ First, without a delegate
+master operation \ => default implementation
+
+\ then with a delegate that does not implement "thing"
+object o
+o master !:
+master operation \ => default implementation
+
+\ and last with a delegate that implements "thing"
+slave master !:
+master operation \ => delegate implementation