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= RECORD (* Abstract *) handle : Handler; END; PROCEDURE Handle* (f : Figure; VAR msg : Message); BEGIN f.handle(f, msg) END Handle; PROCEDURE Init* (f : Figure; handle : Handler); BEGIN f.handle := handle END Init; END Figures.

We extend the generic type Figure to a specific shape:

MODULE Rectangles; IMPORT Figures; TYPE Rectangle* = POINTER TO RectangleDesc; RectangleDesc*

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