🚀 go-pugleaf

In article <...> huangp@wasser.Colorado.EDU (PeiYu Huang) writes:

 >      Well, by "neatly" I mean something other than:
 > 
 >        cl>(setq my-instance (make-instance 'MY-CLASS))
 >           #<MY-CLASS @ .......)
 > 
 >        cl>(setq my-instance NIL)
 > 
 > All suggestions are welcome. Thanks in advance..
 > 

If you don't use global (special) variables, then you don't need to do
anything to eliminate unused instances.  One simple solution would be:


(let ((my-instance (make-instance 'MY-CLASS)))
  ....)

After the let form, my-instance is not bound and the instance of
MY-CLASS that was created is freed for the garbage collector.

Why do you feel a need to destroy instances explicitly?
--

Thomas A. Russ                                             tar@isi.edu    
USC/ISI, 4676 Admiralty Way, Marina del Rey, CA 90292      (310) 822-1511

In article <22625@venera.isi.edu>, tar@ISI.EDU (Thomas A. Russ) writes:
>
>Why do you feel a need to destroy instances explicitly?
>
    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?

P. Huang 

In article <1992Oct13.142031.569@colorado.edu> PeiYu Huang,
huangp@wasser.Colorado.EDU writes:
>    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. 

I may be missing something here, but if the instance belongs to the class 
variable list, and neither belongs to any other set nor is the value of 
any global symbol, then to "destroy" it, by which I infer you mean to 
recover its allocated memory, you need only to remove it from the class 
list. The gc will then recover the memory.

I guess I'm not too certain what you mean by "destroy".


Tim Larkin
Federal Nutrition Laboratory
Tower Road
Ithaca, New York
tsl1@cornell.edu
607-255-7008