More automated interfacing of D with C codebases

[Jacob Carlborg]

On 2012-10-22 20:38, Brad Lanam wrote:

> Huge difference.  It's not necessary to figure out corresponding type
> sizes on every system.  I only need to figure out what needs to be in
> there.  And once all the work of creating the interface file is done,
> the work of porting to another architecture or operating system or
> compiler is much reduced.
>
> It's not necessary to figure out which api calls are macros on arch XYZ
> or are simply not there:
>
> cdcl Tcl_IncrRefCount
> clib Tcl_IncrRefCount
> # if Tcl_IncrRefCount is not defined as a library call, search for the
> macro.
> if lib_Tcl_IncrRefCount ! _clib_Tcl_IncrRefCount
>   cmacro Tcl_IncrRefCount tcl.h void 'Tcl_Obj *'
> endif
>
> My example Tck/Tk conversion doesn't handle 8.6, but the effort to add
> it will be very minimal.  All of the hard work of discovering the needed
> typedefs has been done.
>
>> [...]
>> I don't think SWIG is the right approach because:
>>
>> * You have to create these interface files
>> * It seem to not handle all code
>
> I don't know SWIG, but the idea is the same for my tool.
>
> If you try to automate processing of the pre-processed headers, all of
> the included system headers will be processed and too much that isn't
> needed will be output. The included system definitions will conflict
> with D definitions.
>
> I'm not sure that handling *all* code is necessary.  How often do you see
> this sort of thing in C code?
>      _XPrivate .private9, .private10;
> Rather than spend effort on handling *every* possible obscure C/C++/ObjC
> construct, it's easier to simply handle those in the interface file.
>
> Other constructs that are more common can be added to SWIG or to my tool.
> They're both open source.

I prefer the approach I took when I created DStep, it uses libclang. The 
tool can parse all C(++) and Objective-C(++) code that clang can. 
Although it currently won't generate code for everything, at least it 
doesn't choke any code.

I also get all bug fixes and new languages features for free when 
they're added to clang.

No need to create interface files.

-- 
/Jacob Carlborg