FFI progress

Simon Peyton-Jones simonpj at microsoft.com
Fri Mar 23 04:06:16 EST 2001


The FFI discussion seems to be completely stalled.  Would you,
as our Tsar, like to summarise the state of play, and re-invigorate it?
We don't have a plan at the moment; nor do we have even a draft FFI
document (the one you are going to write!).  I'm concerned that
we'll just dribble on and lose morale.


Here's my contribution to re-invigoration:

As I recall the main sticking point is whether we have a global
'foreign library' declaration in addition to foreign import etc.
The main (only?) motivation for such a thing is


It's a powerful motivation because C is ubiquitous.  I do have
one suggestion to elaborate our earlier proposal.  To remind you
our simple-minded proposal was

* no 'foreign library' decl
* the c-language-specific string on a foreign import could say
	foreign import "gtk:foo" foo :: <type>
  with 'gtk' indicating which foreign package was indicated

Main complaint was: the package-name => what-to-do mapping still isn't
specified.  In short, our simple-minded proposal is too simple-minded to
be useful.

OK so the new suggestion is this: the 'gtk' indicates 'please #include
It's up to you to have a 'gtk.h' lying around, in which you can put all
other #includes (including whether in <> brackets or "" quotes) to your
heart's content.

I bet this still doesn't solve the problem entirely, but maybe it solves
of the problem.  I remain reluctant to generate elaborate designs for a


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