[gclist] Buffy finalizer slayer.

[Simon Peyton-Jones]

> Lets open the medieval text on the evils of finalizers. It 
> has plenty of
> death and destruction but watcher objects seem to solve every problem.

I believe that the Glasgow Haskell Compiler's implementation
of (what we call) finalisers are precisely what
you describe as watcher objects.  There's a paper describing them

	http://research.microsoft.com/~simonpj/papers/weak.ps.gz

(But I could be mistaken; I'd welcome feedback.)

Do any other systems implement watcher objects as you describe them?

Simon