When you need to verify whether the object you got back was a Lecturer, you could do a test something like: 
if (ref($lecturer) eq "LECTURER"){
   # You can do $lecutrerer->get_research();
}else{
  # This dude can't research ...
}

[download]
If there is only a small number of minor differences between the classes, my preferred way would be to add a bit-vector attribute to the "Teacher" class that lists capabilities like "CAN_RESEARCH".

    ..."I don't know what the facts are but somebody's certainly going to sit down with him and find out what he knows that they may not know, and make sure he knows what they know that he may not know, and that's a good thing. I think it's a very constructive exchange," --Donald Rumsfeld

In reply to Re: Inheritance and module cross dependencies by NetWallah
in thread Inheritance and module cross dependencies by prowler

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