On Wed, Nov 04, 2009 at 01:10:17PM +0100, Johan Hake wrote:
On Wednesday 04 November 2009 09:37:55 Garth N. Wells wrote:
kent-and@xxxxxxxxx wrote:
Hi, I am very happy with the Expression, but old code like
class Dabla(Function):
def eval(...)
still works.
The only problem is that the function is zero even though eval is
implemented. Is it
possible to turn this old code into an error?
In C++, no. There is no mechanism in C++ to prevent a user overloading
or hiding a member function.
In Python, using meta classes, yes.
This is a nice exercise for those of you who want to get to know meta classes
in Python. ;) If and when I have time I can fix this. (Heading for the states
next Tuesday)
Should we allow sub-classing of Function, but not overloading of eval?
We could start by disallowing subclassing the Function class and then
if a time comes when someone wants to subclass it, we can rethink it.
