🚀 go-pugleaf

re: Date: Tue, 13 Oct 1992 14:20:31 GMT
    From: huangp@wasser.Colorado.EDU (PeiYu Huang)
    . . .
    Because I use a class variable list to maintain all current instances
    of that class for browsing purpose. One can use a form in an 
    "initialize-instance :after" method to update the list. I guess I may 
    need to define another method to clean up the list BEFORE destroying the
    instance, say my-instance, otherwise when my-instance becomes unbound, I 
    can no longer access the list via it. 

    Any comments?

    Date: Tue, 13 Oct 1992 13:40:40 GMT
    From: jeff@aiai.edinburgh.ac.uk (Jeff Dalton)
    . . . 
    Now, one thing that didn't happen in X3J13's revision of Common
    Lisp was changes to garbage collection to support such things 
    as finalization and weak pointers.  I think it was reasonable
    not to do this, but I want to add my voice to those saying
    "we want it" in the hope that implementors will be influenced.


A "weak-set" is surely the obvious choice, when there is an automated 
garbage colllector, for keeping around a list of all instances of a class.

Lucid's 4.1 release ("on your Sparc desk ``next week'') has both
finalization and weak pointers as first-class, documented facilities;
and I know other vendors have some, possibly undocumented, versions of 
such things too.


-- JonL --