Austin Seipp wrote:
For that matter, "ghc-pkg list | grep -i alex" doesn't list anything, after I cabal-installed it. How does cabal verify the prerequisite alex version? (Or does it?)
ghc-pkg lists libraries that are registered with the ghc package manager (globally and locally); alex is simply an application, not a library, so there's really nothing for GHC to register. As for telling what version is necessary, I haven't the slightest.
Slightly OT, but this division of work between cabal and ghc-pkg has always looked strange to me. Cabal knows better what meta information to store about a package, library or application. IMO the package database should reside with cabal; implementations like ghc or hugs or whatever could query cabal about the information they need (e.g. for building). Cheers Ben