☞

Program Repair Shop

22

Overencapsulation

• %O is overencapsulated

• For example, I cannot override add_observer:

     sub add_observer { 
        ...
        push @{$O{ $item }}, $observer;
        if ( ref( $observer ) ) {
            weaken( $O{ $item }->[ -1 ] );
        }
        ...
     }

• A right way to do this:

        my %Observers;
        
        sub _ob_hash { \%Observers }
        
        sub add_observer { 
           ...
           local *O = $self->_ob_hash;
           push @{$O{ $item }}, $observer;
           if ( ref( $observer ) ) {
               weaken( $O{ $item }->[ -1 ] );
           }
           ...
        }

• Now a subclass can get the base class to store the data somewhere accessible

• By suitably overriding ->_ob_hash

☞

☞