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From: dsr@luke.mitre.org (Douglas S. Rand)
Newsgroups: comp.lang.lisp
Subject: Re: Destructors in Lisp and CLOS
Message-ID: <116718@linus.mitre.org>
Date: 10 Aug 90 15:06:35 GMT
References: <3296@stl.stc.co.uk>
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Reply-To: dsr@luke.mitre.org (Douglas S. Rand)
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In article <3296@stl.stc.co.uk>, skp@stl.stc.co.uk (Steve Perryman ) writes:
|>
|>Is there a standard destructor function in Common Lisp or CLOS ???
|>There is no mention of one in Sonya Keene's book on CLOS, but is there one/
|>going to be one (in current standards etc) ??
|>

Although this might be useful this is not a goal of CLOS.  Also it is generally
antithetical to the view of the LISP world.  It is the job of the GC to clean
up allocated unused storage.

|>
|>I have crashed my application cos it creates reams of temporary objects that
|>need to be destroyed after their use, and the garbage collector cannot
|>handle it. My lisp system has a destructor function but it is definitely
|>non-standard and I want to use something more standard if possible.
|>

A possible work around to your problem is to add a personal destructor function
whose job it is to place an object back on a reuse heap.  You obviously need to
be careful that the object really isn't in use (this is why GC is hard
to write).
There is a generic function reinitialize-instance which might or might not help
you with cleaning the old objects.  But in any case you then need to modify 
make-instance (allocate-instance?) for that class to grab objects off the heap
before allocating a new one.

|>
|>Thanks in advance,
|>
|>Steven Perryman
|>(skp@stl.stc.co.uk)
               
Douglas S. Rand 
Internet:   <dsrand@mitre.org>
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