On Thu, 31 Jan 2013, Thomas Schilling wrote:
I don't think this would work. If "network" still contains a module Network.URI and a package adds a dependency on "network-uri" which also exports a module Network.URI, then you would have to specify the package name in your import, i.e.:
import "network-uri" Network.URI
Then, once Network.URI is removed from "network", users have to edit their sources again to remove the explicit package import. I think the only reasonable way to handle things is to use flags in a .cabal file, i.e., the same way we had to deal with base-3 => base-4 transition (which was very annoying).
An alternative would be to split the "network" package into "network-uri" and "network-socket". Users of network-uri would have to switch to network-socket as well. However, the types of "network" and "network-socket" would be incompatible unless the "network-socket" package re-exports the modules from "network" or vice versa. E.g. could we put this into the "network" package: {-# LANGUAGE PackageImports #-} module Network.Socket ( module S ) where import qualified "network-socket" Network.Socket as S ? Interestingly, the GHC documentation uses Network.Socket for explaining the PackageImports extension.