darcs patch: added cppOptions and c2hsOptions

[Duncan Coutts]

On Wed, 2007-04-04 at 03:33 +1200, Vivian McPhail wrote:

> Wed Apr  4 03:32:49 New Zealand Standard Time 2007  Vivian McPhail
> <omconsult at gmail.com>
>   * added cppOptions and c2hsOptions

Hia Vivian,

Can you explain to me again exactly why we need these extra options? As
I see it, cpp options can just be included in the cc options, is there
any need to separate them?

Cabal currently looks for -D* -U* and -I* flags in the cc options and
passes them to c2hs. Are there any other ones that we are missing there?
It's quite convenient for users not to have to separate the cc flags
into cpp ones, since many other tools intermingle them (off the top of
my head I can think of pkg-config).

As for the c2hs options, again I'm not clear as to why this is
necessary. c2hs doesn't support that many interesting flags:

  -C CPPOPTS   --cppopts=CPPOPTS    pass CPPOPTS to the C preprocessor
  -c CPP       --cpp=CPP            use executable CPP to invoke C preprocessor
  -d TYPE      --dump=TYPE          dump internal information (for debugging)
  -h, -?       --help               brief help (the present message)
  -i INCLUDE   --include=INCLUDE    include paths for .chi files
  -k           --keep               keep pre-processed C header
  -l           --copy-library       copy `C2HS' library module in
  -o FILE      --output=FILE        output result to FILE (should end in .hs)
  -p PLATFORM  --platform=PLATFORM  platform to use for cross compilation
  -t PATH      --output-dir=PATH    place generated files in PATH
  -v           --version            show version information

I think all of these are either not useful or can be selected automatically.

As for the optional .h file that can be passed on the command line, the
better way to do that is to put the #include inside the .chs file.

The alternative is to extend c2hs to accept many .h files on the command
line and we can pass all the files in the 'includes:' field to c2hs. I'm
considering extending c2hs to allow this. I'm also planning to change
c2hs so that the .h file it generates will not clash with anything else,
for foo.chs it'll generate foo.chs.h and possibly foo.chs.c too.

Is there anything I've missed?

Duncan