Re: merging generic methods from different modules

[Mikael Djurfeldt]

"Lars J. Aas" <address@hidden> writes:

> What I think would be desirable is to automatically have the generic
> methods be merged in these cases.  How to accomplish this eludes
> me though.  I figure there is no way to do this with the current
> module-system and goops implementation, right?  How does the future
> look for something like this?  Will the new module system allow
> something like this to be implemented?

This is a topic which has previously caused long discussions.  We
never found a solution which satisfied everybody.

However, I do agree that something like this is desirable.  (I did
actually discuss it with Kent Dybvig and even he thought something
like this might be desirable.)

I have a solution in mind and the current GOOPS source is actually
prepared for this solution.  The basic idea is to make it possible to
create a new generic function from previously existing ones.  However,
there are many complex issues involved:

1. How does it behave wrt the module system?
2. How does it behave wrt changes to the new GF?
3. How does it behave wrt changes to the GFs it is built from?
4. What about software engineering and data abstraction issues?
   (c.f. Kiczales OO library paper)

I'll implement my solution during Christmas.  We'll regard it as a
prototype and let people play around with it and criticise it.  Then
we'll see if we'll keep it or not.  (I might require people to
manually define some C macro when compiling libguile to include it so
that it isn't mistaken for a supported feature before we have tested
it.)

Mikael