Re^4: Private Methods Meditation

Can't speak for tilly, but it's defaintely something that effects pretty much any language, though Perl might be worse off than most. If you have a method in your subclass, you always run the risk that the parent class will define a method with the same name, but with very different functionality.

I don't remember how the method is searched for in Java, but I believe that if you call that method in the parent, then it calls the parent class's version. This isn't true in Perl without some tricks.

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Comment on Re^4: Private Methods Meditation

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Re^5: Private Methods Meditation by Ovid (Cardinal) on Jul 19, 2004 at 20:59 UTC
If you have a method in your subclass, you always run the risk that the parent class will define a method with the same name, but with very different functionality. Not so. In C++, a method must be explicitly declared as virtual if you wish to allow it to be overridden in subclasses. As a result, a if you call a superclass method and that method calls the method `foo()`, it will only grab the subclass `foo()` if the superclass had declared `foo()` as virtual. (At least, that's my understanding. C++ is not my strong suit.) In Java, you can declare a method as `private` and subclasses cannot override that method. I'm still not sure how subclassing messes with something's internals, though. In Perl, it's pretty much a given that this will happen since there is so little support for encapsulation. This ties in with my comments above. I don't know if tilly meant all OO languages. Cheers, Ovid New address of my CGI Course.	[reply]

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Re^5: Private Methods Meditation
by Ovid (Cardinal) on Jul 19, 2004 at 20:59 UTC

If you have a method in your subclass, you always run the risk that the parent class will define a method with the same name, but with very different functionality.

Not so. In C++, a method must be explicitly declared as virtual if you wish to allow it to be overridden in subclasses. As a result, a if you call a superclass method and that method calls the method foo(), it will only grab the subclass foo() if the superclass had declared foo() as virtual. (At least, that's my understanding. C++ is not my strong suit.)

In Java, you can declare a method as private and subclasses cannot override that method.

I'm still not sure how subclassing messes with something's internals, though. In Perl, it's pretty much a given that this will happen since there is so little support for encapsulation. This ties in with my comments above. I don't know if tilly meant all OO languages.

Cheers,
Ovid

New address of my CGI Course.

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