#! /usr/local/bin/perl -wl

use strict;
use Regexp::Assemble;

print Regexp::Assemble->new->chomp->add(<DATA>)->as_string;

__DATA__
^\d{4}-\d{3} \d\d(?:\d\d){2}$
^\d{4}\d{3} \d\d(?:\d\d){2}$
^\d{4}-\d{3}$
^\d{4}\d{3}$
^\d{4}$