How to import Repa

Question

I'm really new to the Haskell world, so please excuse me for the stupid question. I instlled Haskell Platform, I executed cabal install repa and then tried to load a file with this code in WinGHCi

import qualified Data.Array.Repa as R
:m + Data.Array.Repa

but I get this:

Could not find module `Data.Array.Repa'
Perhaps you meant
  Data.Array.Base (from array-0.4.0.0)
  Data.Array.IO (from array-0.4.0.0)
  Data.Array.ST (from array-0.4.0.0)

Could someone please tell me how to remove the problem with not found module? Thank you very much!

Answer 1

I am not sure if this is the case, but did you, actually, look at the status message cabal returned when you attempted installing repa?

On my Windows system the latest (as of today, 2012.4.0.0) Haskell platform fails to install the latest (3.2.3.1) version of repa, e. g. cabal install repa doesn't work, saying that it would cause reinstalling of some system packages, thus possibly breaking the system. If I try installing anyway (with cabal install repa --force-reinstalls), it fails anyway, with an arcane status error message. If, by any chance, you didn't pay attention to the fact that the installation failed, and tried importing it anyway, I think the error message you get will be exactly what you had ("Could not find module...").

I was able, however, to install an earlier version of repa, namely 3.2.1.1, with cabal install repa-3.2.1.1

I haven't tried using it yet, but at least importing and :m + Data.Array.Repa seems to work just fine.