I just did brew install haskell-platform
and it installed The Glorious Glasgow Haskell Compilation System, version 7.6.3 .
$ cabal --version
cabal-install version 1.16.0.2
using version 1.16.0 of the Cabal library
$ cabal update
Downloading the latest package list from hackage.haskell.org
Note: there is a new version of cabal-install available.
To upgrade, run: cabal install cabal-install
$ cabal install cabal-install
Resolving dependencies...
cabal: Could not resolve dependencies:
trying: cabal-install-1.20.0.3
rejecting: zlib-0.5.4.1, 0.5.4.0, 0.5.3.3, 0.5.3.2, 0.5.3.1, 0.5.2.0, 0.5.0.0,
0.4.0.4, 0.4.0.3, 0.4.0.2, 0.4.0.1, 0.4, 0.3, 0.2 (global constraint requires
installed instance)
I don't understand what the problem is here, I just installed everything for the first time.