Hi, I apologise if this has already been asked, but I haven't gone and DLed a news reader yet, so Firefox keeps complaining every time I try to use the search box.

I was planning to include some C source into a D project, and was happily writing the D module for the "header" for the source, when I ran into a little problem. I want to include some const values in the module, which made me realize I don't know how to include the module in the C source. I can see how it would work from the D side of the compilation, but how would I go about making the const values visible to the C code? Do I just #include "d_module.d"? Or is there a different way to do this? What would the compilation process look like for this?

Thank you in advance for any help you can provide.

Reply to Matt,

> don't know how to include the module in the C source. I can see how it
> would work from the D side of the compilation, but how would I go
> about making the const values visible to the C code? Do I just
> #include "
> 

The best approach might be to write a .h file with only the constants in it and then use htod to convert it into a .d header. Aside from that you would end up hand editing bith files.

BCS wrote:
> Reply to Matt,
> 
>> don't know how to include the module in the C source. I can see how it
>> would work from the D side of the compilation, but how would I go
>> about making the const values visible to the C code? Do I just
>> #include "
>>
> 
> The best approach might be to write a .h file with only the constants in it and then use htod to convert it into a .d header. Aside from that you would end up hand editing bith files.
> 
> 

If the constants are in a syntax recognized by both C and D (e.x. they're just integers, or enums), you can write the .h and use D's mixin(import("constants.h")), which would prevent you from having to maintain two files.

If you're using some types differently in each, or want to use #defines on the C side, etc., you could use CTFE to convert (there was a CTFE regex engine floating around somewhere a whiel back... Actually, I'd like to get my hands on that myself if anyone has the link).

Reply to Robert,

> mixin(import("constants.h"))
> 

Darn, now I want to go out and build stuff to do this:

mixin(h2d!(import("stdio.h")));

On Thu, 07 May 2009 03:02:16 +0400, Matt <webwraith@fastmail.fm> wrote:

> Hi, I apologise if this has already been asked, but I haven't gone and DLed a news reader yet, so Firefox keeps complaining every time I try to use the search box.
>
> I was planning to include some C source into a D project, and was happily writing the D module for the "header" for the source, when I ran into a little problem. I want to include some const values in the module, which made me realize I don't know how to include the module in the C source. I can see how it would work from the D side of the compilation, but how would I go about making the const values visible to the C code? Do I just #include "d_module.d"? Or is there a different way to do this? What would the compilation process look like for this?
>
> Thank you in advance for any help you can provide.

Did you try htod? http://www.digitalmars.com/d/2.0/htod.html
There is also BCD http://www.dsource.org/projects/bcd

Try both tools and let us know if it helped.

Denis Koroskin Wrote:

> On Thu, 07 May 2009 03:02:16 +0400, Matt <webwraith@fastmail.fm> wrote:
> 
> > Hi, I apologise if this has already been asked, but I haven't gone and DLed a news reader yet, so Firefox keeps complaining every time I try to use the search box.
> >
> > I was planning to include some C source into a D project, and was happily writing the D module for the "header" for the source, when I ran into a little problem. I want to include some const values in the module, which made me realize I don't know how to include the module in the C source. I can see how it would work from the D side of the compilation, but how would I go about making the const values visible to the C code? Do I just #include "d_module.d"? Or is there a different way to do this? What would the compilation process look like for this?
> >
> > Thank you in advance for any help you can provide.
> 
> Did you try htod? http://www.digitalmars.com/d/2.0/htod.html There is also BCD http://www.dsource.org/projects/bcd
> 
> Try both tools and let us know if it helped.
> 

Thanks, but the problem isn't with my writing the D module for C. It's how the C source imports that module to access the constants in it.

Matt wrote:
> Hi, I apologise if this has already been asked, but I haven't gone and DLed a news reader yet, so Firefox keeps complaining every time I try to use the search box.
> 
> I was planning to include some C source into a D project, and was happily writing the D module for the "header" for the source, when I ran into a little problem. I want to include some const values in the module, which made me realize I don't know how to include the module in the C source. I can see how it would work from the D side of the compilation, but how would I go about making the const values visible to the C code? Do I just #include "d_module.d"? Or is there a different way to do this? What would the compilation process look like for this?
> 
> Thank you in advance for any help you can provide.

I've never tried this, but I guess you'd do something like:

extern(C) void myFunction();

In the D file, compile it, then link the resulting object in when you compile the C app. You would of course need to define this function and anything else you've extern(C)'d in the C app so it's available. I'm guessing that you wouldn't be able to use a large chunk of D's functionality without linking in a good chunk (if not all) of a D runtime too, but I may be wrong.

Matt wrote:
> Denis Koroskin Wrote:
> 
>> On Thu, 07 May 2009 03:02:16 +0400, Matt <webwraith@fastmail.fm> wrote:
>>
>>> Hi, I apologise if this has already been asked, but I haven't gone and  DLed a news reader yet, so Firefox keeps complaining every time I try to  use the search box.
>>>
>>> I was planning to include some C source into a D project, and was  happily writing the D module for the "header" for the source, when I ran  into a little problem. I want to include some const values in the  module, which made me realize I don't know how to include the module in  the C source. I can see how it would work from the D side of the  compilation, but how would I go about making the const values visible to  the C code? Do I just #include "d_module.d"? Or is there a different way  to do this? What would the compilation process look like for this?
>>>
>>> Thank you in advance for any help you can provide.
>> Did you try htod? http://www.digitalmars.com/d/2.0/htod.html
>> There is also BCD http://www.dsource.org/projects/bcd
>>
>> Try both tools and let us know if it helped.
>>
> 
> Thanks, but the problem isn't with my writing the D module for C. It's how the C source imports that module to access the constants in it.

Well, if you write the constants in C, you can have them automatically translated to D in the build process and then just include the result.