On Tue, Jan 11, 2005 at 02:33:52PM +0200, Krasimir Angelov wrote:
I am trying to cabalize HSQL. There is a simple ./configure script which performs some simple checks. Now I would like to perform these checks from Setup.lhs using Cabal hooks. The hooks API looks a little bit strange for me. The preConf hooks returns (Maybe PackageDescription) which after that is merged with the basic description. The Setup.buildinfo file contains only the hooked description instead of merged one. The parser requires to have package name and version, in order to properly parse the description. I need to return the right name and version from preConf hook to satisfy this restriction. I can't do this without re-reading the original description from Setup.description.
I think these checks are off at the moment. But you can get the effect you're after by using main = defaultMainWithHooks defaultUserHooks can't you? (cf fptools/libraries/X11) There's a need to do something different under Windows, though.
Isn't it simpler to change the hooks type to something like:
PackageDescription -> IO PackageDescription
where the argument is the original description and the result is the possible updated one? This avoids the need of merging and simplifies the library code.
This relates to the discussion on package description structure. With this interface, it would be possible for the preConf hook to alter fields that are supposed to be fixed.