Re: Elisp performance

[Daniel Kraft]

Andy Wingo wrote:
> > Daniel Kraft <address@hidden> writes:
> >
> > > Lambda arguments are still always dynamically bound, which is quite a
> > > pity as it inhibits tail-call optimization;
>
> Indeed, a pity. Though self-tail calls can be optimized... still,
> irritating.

Yes, but I fear this will complicate the compiler a lot and does not 
gain that much -- for anyone who wants to use tail-calls, he can do so 
with the always-lexical feature, and existing code should not depend on 
tail-calls anyway as Emacs seems not to do it.

> > The main thing I believe that makes a fluid different from a normal
> > variable is that a fluid can have a different value in each thread -
> > which is not relevant to Elisp.
>
> True. Of course, it would be a nice thing to give to elisp -- I mean,
> currently in Emacs variables have one value per thread as well, it's
> just that there's only one thread. So if we give Emacs the capability to
> run multiple threads (as we should IMO), we should provide thread-local
> values.

I like the idea, too.  In this case, we should stick with the fluids.  I 
also thought about giving the user the choice of which "dynamic binding" 
facility to use, and it would not be that much of a mess, I think; maybe 
I'm going to give dynamic binding without fluids and just dynamic-wind a 
try to see how much performance this really gives.

Cheers,
Daniel

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