[comp.lang.misc] More on unbounded polymorphism

rentsch@unc.UUCP (02/15/87)

In article <540086280.7983@minster.UUCP> martin@minster.UUCP (martin) writes:
> Maybe not a queue... But I can certainly think of a dictionary, the elements
> of which I might want to be absolutely anything. That is the Smalltalk
> system dictionary!! I want this to be able to contain references to
> any object in the system, biteditors, windows, processes etc.
> 
> Of course I don't need, but would also like, the same freedom on
> the types of the keys!

Good example.

To add to the example, remember that (in Smalltalk-80, at least)
'Dictionary' is a subclass of 'Set' (which is a subclass of
'Collection').  So, whatever polymorphism is needed from Dictionary
is also needed from Set (and Collection, etc.).

cheers,

Tim