A question about dynamic typing

[Jon Cast]

Nick Name <nick.name@inwind.it> wrote:
> On Sun, 19 Jan 2003 16:02:41 -0600
> Jon Cast <jcast@ou.edu> wrote:

> > > But, to fully exploit the power of a "functionally-programmed"
> > > desktop, the interface should allow the user to map an operation
> > > onto all the objects of the panel; in this case the allowed
> > > operations should be those that all the object share.

> >  This is fairly easy if you name the operations; then you can use
> >  that to compute the intersection of the operations for all the
> >  types.  If you don't name the operations, then of course the
> >  problem becomes undecidable.

> Another idea: if I allow the list of objects in the panel to be
> infinite,

Sorry, but I'm having difficulty figuring out where you'd get an
infinite list of objects to put in the panel.  I suspect any solution is
going to depend on how the list of objects is put together.

> obviously the set of allowed operations in a map is the set of
> operations on "objects". But if I filter an infinite list of objects
> to all the objects of a certain type, I wish to see all the operations
> on that type in the possibilities for a map.

If you have a finite list of the types of your objects, then you can
list the operations available at each type and use that to get the
intersection, I suppose.

> How would you deal with such a case?

> Vincenzo