Installation of other peoples projects with haskel has been met with varying success.
Hopefully this post helps:
https://pemungkah.com/xmonad-on-os-x-mavericks/
condensed info from that article into a command below: (excluding, XQuartz)
/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)" &&
brew install ghc cabal-install wget &&
cabal update &&
export LIBRARY_PATH=/usr/local/lib:/usr/X11/lib &&
cabal install xmonad
I arrived at the above website from a comment in this stackoverflow answer:
https://stackoverflow.com/a/15239780/5283424
stack-vs-cabal(2015): https://www.fpcomplete.com/blog/2015/06/why-is-stack-not-cabal
how-stack-differes-from-cabal(2018): https://stackoverflow.com/a/30922706/5283424
fun article: http://www.rntz.net/post/2018-05-18-why-i-am-not-a-fan-of-stack.html