Hi,
Am Samstag, den 03.11.2012, 11:26 +0100 schrieb Peter Divianszky:
> > This can be implemented by replacing every record update
> >
> > r' = r { x = y }
> >
> > with
> >
> > r' = r { x = unsafePerformIO (cond-update r r' (x r) y) }
> >
> > where we keep the current record update mechanism and implement
> > cond-update like
> >
>
> cond-update :: r -> r -> x -> IO x
> cond-update r_old r_new x_old x_new = do
> eval x_new
> b <- x_old === x_new
> when b (replace r_new r_old)
> return x_new
>
> > where (===) is pointer-equality and replace is a low-level function
> > which replaces thunks in the heap.I think one problem with this approach is that now, until "x r'" is evaluated, you keep both r and r' alive. If r was _not_ retained by anything else, then you are now preventing the GC from freeing it and hence increasing the memory footprint. Greetings, Joachim -- Joachim "nomeata" Breitner m...@joachim-breitner.de | nome...@debian.org | GPG: 0x4743206C xmpp: nome...@joachim-breitner.de | http://www.joachim-breitner.de/
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