[Haskell-cafe] ANN: bindings-DSL 1.0.4 (Category: FFI)

[Maurí­cio CA]

Hi,

bindings-DSL is a mature and well documented preprocessor domain
specific language you can use to generate bindings to a C API.
It's based on functionality provided by hsc2hs. These are links to
Hackage page and documentation:

http://hackage.haskell.org/package/bindings-DSL
http://bitbucket.org/mauricio/bindings-dsl

New in this version:

* Support for C unions.
* Use of <inttypes.h> macros for wider portability.

An example on the use of unions follow. Suppose you have:

union example {
int k;
char c[4];
};

Then, using bindings-DSL, you'll write:

#starttype union example
#union_field k , CInt
#union_array_field c , CChar
#stoptype

Here is a ghci session showing the resulting code:

> let value = C'example 1 []

> u'example'k value (2^10)

C'example {c'example'k = 1024, c'example'c = [0,4,0,0]}

> u'example'c value [1,0,0,0]

C'example {c'example'k = 1, c'example'c = [1,0,0,0]}

> u'example'c value [0,0,0,1]

C'example {c'example'k = 16777216, c'example'c = [0,0,0,1]}

Peeking an uninitialized memory address:

> v <- alloca $ \p -> peek p :: IO C'example
> v

C'example {c'example'k = 81842189, c'example'c = [13,-48,-32,4]}

Hope it's useful to you. Best,
Maurício

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[Lars Viklund]

On Sat, Jan 23, 2010 at 01:02:07AM -0200, Maurí­cio CA wrote:
> bindings-DSL is a mature and well documented preprocessor domain
> specific language you can use to generate bindings to a C API.
> It's based on functionality provided by hsc2hs. These are links to
> Hackage page and documentation:
>
> http://hackage.haskell.org/package/bindings-DSL
> http://bitbucket.org/mauricio/bindings-dsl

Much thanks for this lovely package.

I'm currently using it to write a low-level Direct3D9 binding and thus
far it's very friendly.

The only thing I've missed for now is a #ccall equivalence for "stdcall"
functions, I hacked one up myself and called it #stdcall, but it would
be nice to have in the package proper if possible.

Keep up the good work,
--
Lars Viklund | z...@acc.umu.se

[Maurí­cio CA]

>> http://hackage.haskell.org/package/bindings-DSL
>> http://bitbucket.org/mauricio/bindings-dsl

> The only thing I've missed for now is a #ccall equivalence
> for "stdcall" functions, I hacked one up myself and called it
> #stdcall, but it would be nice to have in the package proper if
> possible.

Here is my attempt. I added #callconv macro, that accepts a
calling convention parameter. The lines below are now equivalent.

#ccall do_something , CString -> IO CInt

#callconv do_something , ccall , CString -> IO CInt

Would you mind give it some testing (and of course sugestions as
you wish) before I upload it to Hackage? The link below gives
you a few options for download format. Look for version 1.0.5.

http://bitbucket.org/mauricio/bindings-dsl/downloads

There are a few good C libraries that work well under Linux and
Windows (libusb1.0 for Windows is in beta now, for instance). Do
you think we should have a macro that defaults to 'ccall' in Linux
and others and to 'stdcall' on Windows? If so, I would need some
help to avoid portability issues (like a list of platforms and
proper defaults).

Thanks for your toughts,

Maurício

[Lars Viklund]

On Thu, Jan 28, 2010 at 09:36:42PM -0200, Maurí­cio CA wrote:
> > The only thing I've missed for now is a #ccall equivalence
> > for "stdcall" functions, I hacked one up myself and called it
> > #stdcall, but it would be nice to have in the package proper if
> > possible.
> Here is my attempt. I added #callconv macro, that accepts a
> calling convention parameter. The lines below are now equivalent.
>
> #ccall do_something , CString -> IO CInt
> #callconv do_something , ccall , CString -> IO CInt
>

> http://bitbucket.org/mauricio/bindings-dsl/downloads

Builds fine here and looks reasonably fine.

> There are a few good C libraries that work well under Linux and
> Windows (libusb1.0 for Windows is in beta now, for instance). Do
> you think we should have a macro that defaults to 'ccall' in Linux
> and others and to 'stdcall' on Windows? If so, I would need some
> help to avoid portability issues (like a list of platforms and
> proper defaults).

I would guess that any libraries that are written to be portable will
likely use the default (cdecl) as calling convention. I do not expect
that one would see stdcall used outside inherently native headers like
the Windows ones, DirectX, etc.

--
Lars Viklund | z...@acc.umu.se

[Maurí­cio CA]

>> Here is my attempt. I added #callconv macro, that accepts
>> a calling convention parameter. The lines below are now
>> equivalent.

> Builds fine here and looks reasonably fine.

Okay. Package uploaded, documentation updated.

Best,

Maurício