[Einar, I hope you don't mind me posting your reply on the list] On Tue, Nov 30, 2004 at 12:06:46AM +0200, Einar Karttunen wrote:

Ross Paterson writes:

...

True, simple will only get you so far, but the point is you can get quite a bit further for a small cost. (But if you only need the -I options for source files, not Setup.description, then cpp can put them in an extra-cc-opts field.) You could have a configure that calls fltk-config --libs and stashes the result -- a bit clunky, but fits the interface.

Actually cpp cannot do that. If the -I options are not known when the Setup.description is written (otherwise they could be directly specified) there is usually no way of getting them with cpp.

Generally you cannot #include any C headers because that would break cabal (they usually come with extra baggage) and without any #includes, there is very little information to use.

#including a C header generated by configure is precisely what I was proposing to allow. That's what happens now with the fptools libraries. (Though they use installed package descriptions, which also happen to contain enough build information for Hugs.) I know that Cabal doesn't like the blank lines cpp generates, and I was proposing a change (which SimonM had already done on the fptools copy).

If you are thinking about including a generated file with cpp then it is probably simpler to just append things to the Setup description with a script. I cannot think of real scenarios when this would be helpful.

Sven suggested some: name: PACKAGE_TARNAME version: PACKAGE_VERSION maintainer: PACKAGE_BUGREPORT Similarly extra include directories, libraries, etc. In some cases, part of the info will be always the same, but part is system-dependent, so you want to substitute, not just append. Also #if's are very useful.