On Wed, 2008-06-11 at 06:41 -0700, Jonathan Cast wrote:
Yikes. Every time I learn something new about Cabal, it's /always/ some new limitation, never a new feature. Are there any plans to someday permit doing things with Cabal the Cabal developers haven't added specific code for yet?
All these things are already possible (if not easy) using custom code in the Setup.hs script and/or using a ./configure script.
I assume the claim above about cabal-install failing to install such a package is incorrect, right?
Right. cabal-install works perfectly well with packages that use custom Setup.hs scripts. It picks a suitable version of the Cabal library to build them with.
Beyond which, to paraphrase what I tell my boss at work, I can get Setup.lhs to do anything I want, it's written in a Turing-complete language. But I'd rather not use a tool I'm going to have to fight.
The honest situation is this: the Setup.hs can override hooks into pretty much every phase of configuration, build and installation (see UserHooks module) and you can use any of the base and other core libs to do what you want. So yes, you can do pretty much anything, however the API to get information out of Cabal and to use its functions is of variable utility and stability because the API that setup.hs scripts are expected to use has never been carefully delineated or designed. We now know a lot more about how it *should* be designed but that's not of any immediate help to you. So as people say, once you start to need a custom Setup.hs things become rather harder. On the other hand it is still probably a good deal easier than writing a custom build system with make + autoconf and making that easy to deploy. If you find specific tasks you'd like to be able to do but are currently tricky then file feature requests. Duncan