package DEF;
sub new { bless [], shift }

package ABC;
sub new { bless {}, shift }
sub DEF { "ABC's DEF function" }

# still in package ABC!
$x = new ABC;
$y = new DEF;
$z = new DEF::;
print "X=$x\nY=$y\nZ=$z\n";

__END__
X=ABC=HASH(0x8151d6c)
Y=ABC's DEF function=HASH(0x8151b44)
Z=DEF=ARRAY(0x81525c4)