Hi Kathleen,
Is it possible to have a directory with multiple cabal files, telling cabal which file to use for a given install request by passing in a flag, say something like:
cabal install -f pads.cabal
or
cabal install -f forest.cabal
In other words, something like the -f option in make.
I would like to have that feature in cabal, too, and at first glance it looks like a trivial thing to support. Unfortunately, it is not that easy. When we think of build instructions for Cabal, we tend to think of the "pkgname.cabal" file, but in fact that file is only half of it. The other half is "Setup.hs". Now, the vast majority of Haskell packages doesn't use Setup.hs, because building those packages is simple and the default settings hard-coded into Cabal get the job done just fine. There are packages, however, that ship custom written Setup.hs files that contains plenty of complex build know-how. So, instead of saying "cabal install -f pads.cabal", we would really have to say "cabal install -f1 pads.cabal -f2 Setup-pads.hs" or something like that. We *could* do that, of course, but obviously the makers of Cabal felt that it's easier to expect that separate packages live in separate directories, so that Setup.hs can be called "Setup.hs" in every package. Arguably, the choice to include the package name in the name of the Cabal file is inconsistent with that decision, and that inconsistency is confusing. If you look at a random package, then "foo.cabal" feels like a file that's specific to this package, but "Setup.hs" feels like a file that is generic. In fact, both are specific to this package, even though the name of the latter file doesn't make that clear. Take care, Peter