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Program Repair Shop

34

Uniformize interfaces

        sub direct_observers {
          my $self = shift;
          if (ref($self)) {        # Get object member
           return $self->{$self->key} ||= [];
          } else {
            no strict 'refs';
            return \@{$self->classvar};  # Get package variable
          }
        }

• Eventually I got a better idea

• direct_observers abstracts away the decision about where to store the observer lists

• But it's still coupled tightly to the two decisions about where to store them

• Why not decouple these?

        sub direct_observers {
          my $self = shift;
          return ref($self) ? $self->direct_observers_object 
                            : $self->direct_observers_class;
        }

• Then the special knowledge is encapsulated in direct_observers_object and direct_observers_class:

        sub direct_observers_object {
          my $self = shift;
          return $self->{"Class::Observable::_observers"} ||= [];
        }
        
        sub direct_observers_class {
          my $class = shift;
          no strict 'refs';
          return \@{"$class::Class_Observable_observers"};
        }

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