[Haskell-beginners] Install mess

[Daniel Trstenjak]

Hi Lawrence,

On Mon, Jan 28, 2019 at 09:37:23PM -0600, Lawrence Bottorff wrote:
> So I've set up the Herbert V. Riedel PPA
> 
> sudo add-apt-repository ppa:hvr/ghc
> sudo apt-get update
> 
> then I installed ghc-8.6.3 and cabal-install-2.4
> 
> sudo apt-get install ghc-8.6.3
> sudo apt-get install cabal-install-2.4
> 
> . . . and stuff seems to be installing. However a check finds no cabal and ghc version 8.2.2
> 
> What am I missing?

Herbert's ppa installs 'ghc' to '/opt/ghc/8.6.3', certainly the same is the case for 'cabal-install'.
Below '/opt/ghc' you can have multiple installed ghcs at once.

The easiest way to configure which ghc should be used is by defining a
GHC_VERSION environment variable:

   export GHC_VERSION=8.6.3
   export PATH=/opt/ghc/$GHC_VERSION/bin:$PATH


Grettings,
Daniel