Classes

• Overall, I think my decision to put observer lists into the objects is a good one

• In many ways, it simplifies the code

  • It certainly clears up a bunch of nasty and otherwise insoluble bugs

• But in some ways it complicates things

• For example, Class::Observable allows:

        Alarm->add_observer($guard);

        $alarm = Alarm->new();
        $alarm->notify_observers(...);   # Notifies $guard

• Where to store the observers for class Alarm?

• Answer: In a package variable in the class

• But object member data and package variables are accessed differently

  • This was not a problem when it all went into %O

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Copyright © 2006 M. J. Dominus