[slime-devel] Re: weak hash tables and presentation

[Geo Carncross]

On Feb 4, 2008 10:17 AM, Helmut Eller <heller at common-lisp.net> wrote:
> > Perhaps a better way to deal with this is to have
> > slime indicate what objects its holding and/or clear this buffer when
> > it stops using them. This might better belong in a per-connection
> > thing, and I wanted some advise on this before I started hacking on
> > this.
>
> That sounds like a quite a bit of work.  Don't know if it's worth to
> bother.  Presentations work also with normal (non-weak) hashtables and
> there is already a command to manually clear all presentations on the
> Lisp side.

Really? I guess it'd require saving *presentation-id-to-object* and
*object-to-presentation-id* in the connection. Maybe instead a
connection-closed-hook could look at the existing tables and clear off
any entries that belonged to that connection. I don't know right now,
I'd have to think about this more, but it doesn't seem to actually
need to be that much work.

It's just at that point, weak hash tables wouldn't contribute anything
(that I can see), so it'd be a lot of code that could be removed.

> > Would it be better still to add weak hashtables to ECL anyway.
>
> There are probably uses for weak hashtables outside of Slime.  But it
> might be better to spend the time on other features like better
> source-location tracking etc.

This is true. I was hoping for some low-hanging fruit initially on the
ECL-side since source-location tracking and proper arglist tracking
would require deeper changes to ECL.