help.nix

{
fixup = options: name: file: stdenvNoCC.mkDerivation
  ( options //
    { inherit name;
      installPhase =
        ''cp -r ${file} $out
        '';
    }
  );
wrap = { paths ? [], vars ? {}, file ? null, script ? null, name ? "wrap" }:
  assert file != null || script != null ||
    abort "wrap needs 'file' or 'script' argument";
  with rec
    { set = n: v:
        "--set ${escapeShellArg (escapeShellArg n)} " +
        "'\"'${escapeShellArg (escapeShellArg v)}'\"'";
      args =
        (map (p: "--prefix PATH : ${p}/bin") paths) ++
        (attrValues (mapAttrs set vars));
    };
  runCommand name
    { f =
        if file == null then writeScript name script
        else file;
      buildInputs = [ makeWrapper ];
    }
    '' makeWrapper "$f" "$out" ${toString args}
    '';
}