anchor.diff:  
       # BEAM
       beam.interpreters.erlangR19
  +    # FIXME: erlang
   
       # C/C++
       cc
  
positive.code:     # autoenv_fish = pkgs.callPackage ./pkgs/misc/autoenv_fish { };
      # camlp5 = pkgs.ocamlPackages.camlp5_6_strict;
      # camlp5 = pkgs.ocamlPackages.camlp5_6_transitional;
      # gcc = pkgs.gcc6; # FIXME
      haskellPackages = pkgs.haskellPackages.override {
        overrides = self: super: rec {
          idris = pkgs.haskell.lib.dontHaddock super.idris;
        };
  
negative.code:     # emacs # NOTE: use Homebrew for now
  
      # Theorem Proving
      AgdaStdlib
      coq
  
      # Tools
  