Re: FFI

[joakim]

Zajcev Evgeny <address@hidden> writes:

> Florian Weimer <address@hidden> writes:
>
>> * Zajcev Evgeny:
>>
>>> As you can see there are only strings, and numbers (boolean type is
>>> done via dinamic type/value translators implemented in ffi)
>>
>> Numbers are problematic because SQLite can return 64 bit signed
>> integers.  AFAICS, those are readily represented on SXEmacs, but not
>> on Emacs.
>
> that won't be a problem to get it working after all, you can represent
> ffi data on lisp level as you want it to, using types translators.
> Types translator is lisp level thingie..
>
> my interest is to have compatible FFI in GNU Emacs and (S)XEmacs (at
> least on high level, read lisp level), so two communities could reuse
> bindings.  SXEmacs already have working and pretty tested interfaces
> to:
>
>  - Xlib
>  - curl
>  - sqlite
>  - Wand        
>  - libgcrypt
>
> and few others.
>
> Wand bindings enabled us to implement pretty astonishing image
> viewer/editor inside SXEmacs, it can even do red-eye reduction on
> production level and mordern liquid rescale :) - to get more about, it
> click on:
>
> http://sxemacs-en.blogspot.com/2009/12/wand-mode-image-viewer.htmland
> http://sxemacs-en.blogspot.com/2009/12/wand-mode-new-features_27.html
>
> bindings implementations mostly does not use any SXEmacs specials, the
> code is very common and I'm pretty sure it can be used in GNU Emacs
> without much problems.
>
> We are also working on some complex, but interesting bindings to
> libtelepathy in order to create tool for multiprotocol IM and
> collaborative editing in SXEmacs.  This is pretty time consuming task
> and we surely need a help, if GNU Emacs community will have same FFI
> API then we could unite our efforts to enhance Emacsen..
>
> As I noticed before, I can port and maintain FFI implementation for
> GNU Emacs, but i need some kind of guaranties that community will
> accept it, so my work won't be a waste of time..

My understanding is that a FFI for Emacs must comply to a
interface, which is not yet defined. This interface will probably be similar
to the plugin api in GCC. Basically, the dll to be loaded must export a GPL
compliance symbol. It ought to be possible to add this check to your FFI
implementation, when running in Emacs, even if you do not use it in SXEmacs.


> thanks
-- 
Joakim Verona