Subject: Re: Wishlist: support > 10 args to foreign functions

From: Andy Wingo <[email-masked]>
Date: Mon, 25 Feb 2013 10:01:41 +0100

On Mon 25 Feb 2013 01:34, Mark H Weaver <[email-masked]> writes:

> The current limitation of 10 arguments to foreign functions is proving
> to be a problem for some libraries, in particular the Allegro game
> library.
>
> Is there a reason why raising this limit to 16 or 20 would be
> undesirable?  What tradeoffs are involved?

Each arity of foreign functions gets a little VM program stub that
checks the argument count then actually does the call.  We statically
generate the first N of those arities (currently 10), and then for the
rest we should dynamically allocate the objcode stubs.  Dynamic
allocation is currently unimplemented.

We could raise the pregenerated size, but I think it would be better to
do the dynamic allocation thing.

Andy
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