default.nix

{ nixpkgs ? import <nixpkgs> {}, compiler ? "ghc864" } :
let
  myHaskellPackages = nixpkgs.pkgs.haskell.packages.${compiler}.override {
    overrides = self: super: rec {
    pandoc-include-code  = self.callCabal2nix "pandoc-include-code" (./pandoc-include-code) {};
    };
  };
  gitchapter = myHaskellPackages.callCabal2nix "gitchaper" (./.) {};
in
  myHaskellPackages.callPackage (gitchapter) { }