Managing Multiple GHC Distributions

UNMAINTAINED: I no longer use this. There are now better ways to do similar things.

The multi-ghc repository contains tools for managing multiple distributions of GHC in a single system. It simplifies the installation process and switching the current environment to use one GHC+Cabal.

What's Inside

• ghc-config - A Bash script that sets up the environment and switches between GHC+Cabal paths. This works primarily using directory conventions and symbolic links.

• Makefile - For symplifying the building of Linux binary tarballs.

How to Use

1. Create a directory for your GHC distributions. We'll call this directory $GHC_DISTRIBUTION_DIR for now.

2. Clone this repository into $GHC_DISTRIBUTION_DIR.

3. Add the following to your startup scripts (i.e. your .bashrc or .bash_profile):

   # These environment variables are only necessary if you don't use the defaults
   # shown.
   GHC_DISTRIBUTION_DIR="/opt/ghc"
   GHC_CONFIG_DIR="$HOME/.ghc-config"
   CABAL_USER_DIR="$HOME/.cabal"
   
   # Add the paths for ghc-config, ghc, and cabal-installed binaries. Use
   # the actual paths if you don't set the variables above.
   PATH=$PATH:$GHC_DISTRIBUTION_DIR/bin  # ghc-config
   PATH=$PATH:$GHC_CONFIG_DIR/ghc/bin    # ghc
   PATH=$PATH:$CABAL_USER_DIR/bin        # cabal and cabal-installed binaries
   
   # Initialize the current configuration for this session.
   ghc-config -i
   

4. Install a GHC distribution into sudirectories of $GHC_DISTRIBUTION_DIR/$GHC_VERSION/src, where $GHC_VERSION is that particular GHC version number. For example:

   $ ls /opt/ghc/6.10.4/src
   ghc-6.10.4/  ghc-6.10.4-i386-unknown-linux-n.tar.bz2
   

5. Create a symbolic link to the included Makefile in $GHC_DISTRIBUTION_DIR.

   $ cd /opt/ghc/6.10.4
   $ ln -s ../Makefile
   

6. Install the $GHC_VERSION of GHC using the Makefile. This will use the directory and naming conventions established by the previous steps. See the `Makefile for details.

   $ make install
   

7. Restart your shell.

8. Run ghc-config to see the help information.

9. Run ghc --version to confirm that GHC works.

10. Install cabal by downloading the latest tarball and running the bootstrap.sh script.

11. Run cabal --version to confirm that cabal-install works.