Re^2: Still not getting it: hashref OO class variables

Referencing class data in an object method directly makes it hard to cleanly override the object method in a sub-class. How would you write an overridden wear_out_sole()?

But it wasn't hard, and seems to work fine, as shown above in the original post (you might not've noticed that it was indeed overridden in the Boot class). Is there anything wrong with Boot::wear_out_sole in the OP?

I think there's something I'm missing here. In your comment, are you implying that a subclass should be able to access class data (since a Boot *is*, after all, a Shoe)?

All that aside, I think you'll find that it's pretty unusual to use class data in a real OO system.

Yes, I think I'm noticing that. Thank you. The only example I ever see is when a class wants to keep a total of objects. And for something that simple, there are other ways of doing it (like just incrementing a global every time you instantiate an object, or counting rows in a db table, or keeping the objects in question in a list (then you know the length of the list)).

Comment on Re^2: Still not getting it: hashref OO class variables

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Re^3: Still not getting it: hashref OO class variables by chromatic (Archbishop) on Feb 15, 2008 at 00:55 UTC
In your comment, are you implying that a subclass should be able to access class data (since a Boot is, after all, a Shoe)? Maybe not class data, but definitely class behavior -- and tracking the number of shoes in the system is behavior.	[reply]
Re^4: Still not getting it: hashref OO class variables by bramble (Beadle) on Feb 15, 2008 at 01:31 UTC
In your comment, are you implying that a subclass should be able to access class data (since a Boot is, after all, a Shoe)? Maybe not class data, but definitely class behavior -- and tracking the number of shoes in the system is behavior. Ah, ok. Then here is the crux of the matter: Should the subclass be able to access class behaviour as if that behaviour were a part of the subclass itself (since a Boot is a Shoe)? Or should the subclass simply access class behaviour via the superclass?	[reply]
Re^5: Still not getting it: hashref OO class variables by dsheroh (Monsignor) on Feb 15, 2008 at 16:35 UTC
In general, a subclass should access superclass behaviour via the superclass. That's kind of the point of inheritance, no? Plus it also saves you from having to remember to update all the subclasses every time the superclass behaviour changes.	[reply]