#~ two digits,
#~ followed by a dash,
#~ followed by an optional digit,
#~ followed by four digits 
use Regexp::English;
my $re = Regexp::English
                -> new
                -> digit
                -> digit
                -> literal('-')
                -> optional
                    -> digit
                -> end
                -> digit
                -> digit
                -> digit
                -> digit;
print $re;
__END__
(?^:\d\d\-(?:\d?)\d\d\d\d)

##</code><code>##

\d             Match a digit

\d             Match a digit

\-             Match a literal '-' character

(?:            The start of a non-capturing group

  \d?            Match a digit, one-or-zero times (as many as possible)

)              The end of non-capturing group

\d             Match a digit

\d             Match a digit

\d             Match a digit

\d             Match a digit