foreach ( sort gs::long_strings_first @$raw_hash_keys_ar ) {
    #do_stuff;
}

package gs;
sub long_strings_first($$) {
    return 0 unless defined $_[0];
    return 0 unless defined $_[1];

    length $_[1] <=> length $_[0]
                 ||
        lc $_[1] cmp lc $_[0]
}