C preprocessor + WinHugs

[Ross Paterson]

On Sun, Oct 30, 2005 at 02:18:09PM +0000, Neil Mitchell wrote:
> I'm looking into implementing C preprocessing in WinHugs. I've looked
> around and bundling a copy of cpphs seems like the best solution,
> since few windows users will have a cpp hanging around somewhere that
> can be found.

Hugs uses cpphs for preprocessing the libraries, so there should already
be a copy in the distribution.

> I've hacked together a basic implementation, the only
> thing is that its a lot slower, mainly because its being run on every
> single file which is completely unneeded.

Are you using -F?  Actually the preprocessor is run twice on most files,
due to the way Hugs handles imports.

> Is there some way to detect if a hs file requires preprocessing? If
> not, its almost going to be better to stick with no preprocessing, and
> have a faster development environment. The ways I thought of were:
> 
> * Add some magic to the parser, so that if it encounters a # at the
> start of a line, it bails out and restarts again after preprocessing.
> 
> * Only preprocess .cpp.hs or .hscpp or some other special suffix as
> having cpp directives.
> 
> * Look into the file for some sort of command line arguments pragma on
> the first line denoting preprocessing.

None are terribly attractive (and they would only be for cpp).