shell.nix

{ nixpkgs ? import <nixpkgs> {}, compiler ? "ghc821" }:
let
#  compare-ticky = nixpkgs.callPackage ./nofib/compare-ticky.nix {} ;
  hp = nixpkgs.haskell.packages.ghc821.override {
        overrides = self: super: {
          Cabal = self.callPackage ./Cabal.nix {};
          cabal-install = self.callPackage ./cabal-install.nix {};
        };};
in
nixpkgs.stdenv.mkDerivation {
  name = "env";
  buildInputs =

  nixpkgs.haskell.compiler.ghcHEAD.buildInputs
  ++ [ nixpkgs.perl nixpkgs.ag nixpkgs.haskell.compiler.ghc821  #compare-ticky
      nixpkgs.haskell.compiler.ghc7103
      nixpkgs.haskell.compiler.ghc784
  #  nixpkgs.cabal-install
      hp.cabal-install
      nixpkgs.dnsutils
  ] ;
  shellHook =''
    alias ghc=/root/ghc/inplace/bin/ghc-stage2
    ./head.hackage.sh update
    '';
}