[Haskell-cafe] FFI question

[Duncan Coutts]

On Thu, 2006-02-09 at 09:27 -0800, Donn Cave wrote:
> On Thu, 9 Feb 2006, Christopher Brown wrote:
> > Frederico,
> > 
> > Have you tried using Green Card?
> > 
> > http://haskell.org/greencard/
> > 
> > It is basically a foreign function pre-processor for Haskell. It  
> > allows your Haskell programs to interface with C libraries in a very  
> > straight forward way.
> 
> I tried it, and managed to get it working to some extent.  Then
> I found out about hsc2hs and the current FFI support in ghc, and
> I noticed that according to http://www.haskell.org/greencard/ ,
> the current version of Green Card is an alpha release from 2003.
> 
> >From comparison of the two, my impression is that this parrot is
> dead, and everyone is just too polite to say so.  Unfortunately,
> this inability to pull the shades on Green Card, Haskell Direct,
> etc., takes away a little from ghc's outstanding FFI.

There is also c2hs which is well supported and is used for several large
C bindings:

http://www.cse.unsw.edu.au/~chak/haskell/c2hs/

It works at a higher level than hsc2hs and can make writing bindings
quite a bit simpler and cleaner. For example the cairo bindings use it:

http://darcs.haskell.org/gtk2hs/cairo/Graphics/Rendering/Cairo/

see the various .chs files, for example:
http://darcs.haskell.org/gtk2hs/cairo/Graphics/Rendering/Cairo/Internal/Drawing/Paths.chs

Duncan