Re: Better support for garbage collection

[Brian Rogoff <bpr@shell5.ba.best.com>]

On Wed, 14 Mar 2001, Robert A Duff wrote:
> I too think it would be cool if GC for Ada were widely available.
> But I think youll have a hard time convincing others.  After all, any
> implementation is allowed to provide GC, but nobody has done so, except
> when the GC is unavoidable (the Ada 83 implementation on top of the
> Symbolics Lisp Machine, and the Ada 95 implementations on top of the
> JVM).  Why not?
> 
> Robert Dewar would argue that it's because nobody wants it (at least,
> nobody wants it enough to pay for it).  A more pessimistic take on this
> is that all the folks who understand the glorious benefits of GC have
> long since abandoned Ada in favor of "better" languages.

IMO, just tacking on GC to an existing language doesn't make it very 
much better. When the language designers design a language with the 
expectation of GC, they may then support some higher level features, 
like first class functions, which do make the language much better. 
Ada is far less leaky than C family languages, so the win of just 
adding a GC seems smaller for Ada. 

Of course, you still have designers who blow it by putting in GC and 
omitting such features, but then after a few years they realize they 
screwed up and hack in such things. Java and Eiffel are good examples 
of such screw ups (nested/anonymous classes and "agents"). 

> It is also possible to use Boehm's conservative collector with Ada.
> Does anybody do so?
> 
> (I find the idea of conservative collection somewhat distasteful,
> but it does seem to work in many cases.)

Maybe if it were called a "probabilistic garbage collector" you wouldn't 
mind? ;-)

Didn't Norman Cohen have a proposal for a storage pool extension that 
provided some support for garbage collection? I thought so, but my neural 
garbage collector seems to have reclaimed that hunk of my brain...

-- Brian