Using packages.conf.d for Haskell libraries
Reading the source can pay off. I found this gem in
> getSystemPackageConfigs :: DynFlags -> IO [FilePath]
> getSystemPackageConfigs dflags = do
> -- System one always comes first
> let system_pkgconf = systemPackageConfig dflags
> -- allow package.conf.d to contain a bunch of .conf files
> -- containing package specifications. This is an easier way
> -- to maintain the package database on systems with a package
> -- management system, or systems that don't want to run ghc-pkg
> -- to register or unregister packages. Undocumented feature for now.
> let system_pkgconf_dir = system_pkgconf <.> "d"
> system_pkgconf_dir_exists <- doesDirectoryExist system_pkgconf_dir
> system_pkgconfs <-
> if system_pkgconf_dir_exists
> then do files <- getDirectoryContents system_pkgconf_dir
> return [ system_pkgconf_dir </> file
> | file <- files
> , takeExtension file == ".conf" ]
> else return 
I'd say that using that is much simpler than either calling ghc-pkg in
individual postinst/postrm or using triggers in the ghc6 package.
packages.conf.d is already supported by both ghc and ghc-pkg.
Also, I'd like to move packages.conf to /var/lib/ghc-$version/ in the
next version. IMHO, it's more of a /var than a /usr thing.
I'd like to patch haskell-devscripts to install a
$cabalname-$version.conf file to /var/lib/ghc-6.10.2/packages.conf.d/
when uploading ghc 6.10.2. Any comments on this? Anyone seeing this
interfere with how people like to use ghc-pkg locally?