'Zoo'->diff( 'Zoo'->new(qw( Dog Fox Wolf )),
             'Zoo'->new(qw( Fox )));


##</code><code>##

Can't use an undefined value as an ARRAY reference at ./zoo.pl line 40.


##</code><code>##

($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,