[Haskell-cafe] Cabal dependencies

[Andres Löh]

>>> Do you have any suggestions to install xmobar in this particular case?
>>
>> In case of executables I usually rm -rf ~/.ghc, cabal install,
>> and rm -rf ~/.ghc again. Executables are still here (in ~/.cabal/bin),
>> but all libraries are lost. Warning: it may break your development
>> environment, so make sure you know what you are doing.
>>
>> Better solution could be sandbox tools like cabal-dev. They alloy you to
>> setup development environment per project.

In this particular case, removing all libraries is total overkill.
That should be reserved for situations where the package DB is already
broken, but afaiu, this has not happened here yet.

I'm quite convinced xmobar-0.15 actually works with the more recent mtl. So
you can try:

$ cabal unpack xmobar
$ cd xmobar-0.15

edit the xmobar.cabal file and remove the upper bound from mtl

$ cabal install

Cheers,
  Andres