{
  my $want_pp;
  sub want_pp {
    return $$want_pp if defined $want_pp;
    my $pp_only = parse_args()->{PUREPERL_ONLY};
    $pp_only = !!$pp_only if defined $pp_only;
    $want_pp = \$pp_only;
    $pp_only;
  }
}
