title: How do you install the Haskell Platform over a previous install?
body: <p>I've been working with Haskell lately, and installed gtk2hs (a gtk library for Haskell) a few days ago using MacPorts. For some reason, MacPorts saw fit to install GHC 6.10 over my previous GHC 6.12 install, but I didn't really care.</p>
  
  <p>Now I find myself desiring the improved parallelism support of the latest Haskell Platform, so I installed it today, and it installed successfully - except that when I type in "ghc -v" in Terminal, I am informed that I have GHC 6.10 still.</p>
  
  <p>I have tried using uninstall-hs, and it informs me that I have three Haskells on my system: versions 6.12, 6.12.3, and 7.04. I'm not sure how that 6.12.3 showed up, and what happened to the 6.10? Most importantly, how can I start running version 7.04? Thanks in advance for your help!</p>