Newbie Question - Overloading ==

[bruno.desthuilliers at gmail.com]

On 31 mar, 20:09, Duncan Booth <duncan.bo... at invalid.invalid> wrote:
> xkenneth <xkenn... at gmail.com> wrote:
> > Now obviously, if I test an instance of either class equal to each
> > other, an attribute error will be thrown, how do I handle this? I
> > could rewrite every __eq__ function and catch attribute errors, but
> > that's tedious, and seemingly unpythonic. Also, I don't want an
> > attribute error thrown whenever two classes are compared that don't
> > have the same attributes.
>
> > I have a sneaky feeling I'm doing something completely unpythonic
> > here.
>
> Surely an A isn't equal to every other object which just happens to have
> the same attributes 'a' and 'b'?

And why not ?-)

> I would have thoughts the tests want to be
> something like:
>
> class A:
>     def __eq__(self,other):
>          return (isinstance(other, A) and
>             self.a == other.a and self.b == other.b)
>
> (and similar for B) with either an isinstance or exact match required for
> the type.

I don't think there's a clear rule here. Python is dynamically typed
for good reasons, and MHO is that you should not fight against this
unless you have equally good reasons to do so.