Re: GHC 7.8 release?

Hi Bryan, On 8 Feb 2013, at 11:53, Bryan O'Sullivan wrote:

On Fri, Feb 8, 2013 at 1:29 AM, Tim Watson wrote: Likewise, I'm in the process of setting up Elastic Bamboo on EC2 for Cloud Haskell and would be very interested in seeing how you've dealt with multiple versions of GHC.

It's easy to parameterize builds in Jenkins based on different values of an environment variable, so Johan and I just have different versions of GHC installed side by side, and then set $GHC_VERSION to "7.6 7.4 7.2 7.0 6.12" (or whatever), put /usr/local/$GHC_VERSION/bin at the front of $PATH, and the right thing happens.

Ok cool, that's pretty much what I had in mind but I wasn't sure about installing dependencies and using cabal-install. In my development environment I quickly found that installing multiple GHCs and haskell-platform releases got a bit messy, so I was wondering if there was a recognised 'best way' to do this. I'll probably replicate what I've done with other things (such as Erlang) and manage it with ${PREFIX}/ghc/versions/... and symlink ${PREFIX}/ghc/current/... to avoid the path switching. Hopefully telling cabal-install to use ${PREFIX}/ghc/current/lib will 'just work' when installing dependencies as I switch between ghc versions. Cheers! Tim