opts_set(opts.flags, FALSE_EMPTY_STRINGS, false);
opts_set(opts.flags, TRUE_EMPTY_STRINGS, true);
opts_set(opts.flags, LOOP_LABELS, true);
opts_set(opts.flags, FALSE_EMPTY_STRINGS, false);
opts_set(opts.flags, TRUE_EMPTY_STRINGS, true);
opts_set(opts.flags, LOOP_LABELS, true);