Try Backpack: <code>ghc --backpack</code> October 10, 2016
Backpack, a new system for mix-in packages in Haskell, has been released with GHC 8.2. Although Backpack is closely integrated with the Cabal package system, it’s still possible to play around with toy examples using a new command ghc --backpack. Before you get started, make sure you have a recent enough version of GHC:
ezyang@sabre:~$ ghc-8.2 --version
The Glorious Glasgow Haskell Compilation System, version 8.2.1
By the way, if you want to jump straight into Backpack for real (with Cabal packages and everything), skip this tutorial and jump to Try Backpack: Cabal packages.