use strict;
use warnings;

use URI qw( );

for (
   'http://www.example.com/cgi.pl?x=y#anchor',
   'http://www.example.com/cgi.pl?x=y',
   'http://www.example.com/',
   'http://www.example.com',
) {
   my $uri = URI->new_abs('/', $_);
   print("$uri\n");
}