[Tutor] Follow up to 'class data'

Andrei Kulakov ak@silmarill.org
Tue, 04 Dec 2001 13:02:45 -0500

On Tue, Dec 04, 2001 at 05:33:28PM -0000, alan.gauld@bt.com wrote:


> Interestingly there are some objective data to suggest that 
> inheritance can actually be detrimental to maintenance since
> it is much harder to ensure that a code fix in one place won't 
> cause damage some place else that inherits the changed code.

Let's say you inherit B from class A. If you change A and it
messes up B, the way I see it, could mean 2 things: either
B isn't really a subset of A and shouldn't have been inherited
from it, or the change was too broad, and you should've instead
derived another child class C from A and changed C.. That's
theory, I don't know how it pans out in practice.. and you know
what they say about the difference between theory and practice:
in theory, there is no difference, but in practice, there is :P

Thanks a lot - your post was very helpful. I had some general
idea about this stuff but it was very disorganized and I wasn't
sure about the terminology..

> Also the lack of local visibility of the functions can make 
> code comprehension more difficult. This is one area where 
> python and its explicit use of self and the imported module 
> names actually helps a lot.
> Alan g

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