An @-sign in a box, in haskell

Initial commit of a Haskell version of Xanthous, written using Brick and
built with Nix.

This is so much nicer and so much easier

default.nix

@@ -0,0 +1,8 @@
+{ nixpkgs ? import <nixpkgs> {}, compiler ? "ghc865" }:
+let
+  inherit (nixpkgs) pkgs;
+  all-hies = import (fetchTarball "https://github.com/infinisil/all-hies/tarball/master") {};
+  hie = all-hies.selection { selector = p: { inherit (p) ghc865; }; };
+  xanthous = pkgs.haskellPackages.callPackage ./xanthous.nix {};
+in
+xanthous // { inherit hie; }