{ stdenv, foo, bar ? false, ... }: /* * foo */ let a = 1; # just a comment b = null; c = toString 10; in stdenv.mkDerivation rec { name = "foo-${version}"; version = "1.3"; configureFlags = [ "--with-foo2" ] ++ stdenv.lib.optional bar "--with-foo=${ with stdenv.lib; foo }" postInstall = '' ${ if true then "--${test}" else false } ''; meta = with stdenv.lib; { homepage = https://nixos.org; }; }