On Tue, 2009-01-13 at 20:58 +0100, Bas van Dijk wrote: > > Could not find module `Data.Generics': > > it was found in multiple packages: base-3.0.3.0 syb > > cabal: Error: some packages failed to install: > > json-0.4.1 failed during the building phase. The exception was: > > exit: ExitFailure 1 > > The standard solution for this is to add a cabal flag that controls > wether to depend on base-4 or base-3:
Note that in future it will be even easier. As of Cabal-1.6 (which comes with ghc-6.10 but works with older versions too) you can use CPP macros: > #if MIN_VERSION_base(4,0,0) > import Data.Data (Data) > #else > import Data.Generics (Data) > #endif and not have to do anything in the .cabal file. Of course this does not really help you for base 3 / 4 because the only point of doing that is to preserve compatibility with ghc-6.8 and out-of-the-box ghc-6.8 comes with an older Cabal version and we generally cannot expect all users to upgrade their Cabal version. Duncan _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
