FFI question -- was: [Haskell-cafe] New slogan for haskell.org
dons at galois.com
Wed Dec 19 22:07:31 EST 2007
> On Dec 11, 2007 11:16 PM, Don Stewart <dons at galois.com> wrote:
> > > 2. It offers strong support for integration with other languages and tools
> > > (FFI? Is the support strong?)
> > 2. The FFI in Haskell is perhaps the most powerful out there.
> > You can import C or export Haskell to C with a single line FFI decl.
> I am a newbie on FFI, but have been interested in looking into it. If
> I google on "haskell FFI", what I find is typically:
> 1. The official Haskell 98 FFI 1.0
> 2. The FFI preprocessor -- greencard on haskell.org, where several
> other preprocessors are listed (in the Link section): HaskellDirect, C
> to Haskell, hsc2hs (included in GHC distributions), QForeign, KDirect.
Right. Most of those are out of date.
> The FFI 1.0 API is certainly the most robust tool. However, the
> existence of preprocessors seem to suggest (at least very enticing)
> that the use of a preprocessor would make life easier.
Yes, that's the foundation.
> But when I dig deeper, several of them have not had any release in
> (more than) 3 years. The only exception seem to be "C to Haskell",
> which is part of gtk2hs, and hsc2hs, being part of GHC. It immediately
> becomes confusing which tool I should use if I were to work on a FFI
> project... Can you shed some light on this?
There are three approaches, depending on the size of your project.
Write your ow FFI decls manually.
- Good when you have a small job
- and the C types are simple
- good for more complex C code. Scales nicely. But a bit tedious.
- more automated than hsc2hs
- less common
I use hsc2hs mostly.
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