On Tue, Jan 13, 2009 at 8:47 PM, Alex Ott <alex...@gmail.com> wrote: > Hello > >>>>>> "SF" == Sigbjorn Finne writes: > SF> Hi, a new release of the 'json' package is now available via hackage, > SF> version 0.4.1 > > SF> http://hackage.haskell.org/cgi-bin/hackage-scripts/package/json > > I tried to upgrade it via cabal on mac os x & linux (both use ghc 6.10.1) > and it fails with > > Building json-0.4.1... > > Text/JSON/Generic.hs:33:7: > 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: ------------------------------------------------------ flag small_base description: Choose the new smaller, split-up base package. Library if flag(small_base) Build-Depends: base == 4.*, syb CPP-Options: -DBASE_4 else Build-Depends: base == 3.* ------------------------------------------------------ And use some CPP in your modules like this: ------------------------------------------------------ {-# LANGUAGE CPP #-} #ifdef BASE_4 import Data.Data (Data) #else import Data.Generics (Data) #endif ------------------------------------------------------ See for example how I do it in http://code.haskell.org/Stream regards, Bas _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe