Inefficiency of __getattr__

[Huaiyu Zhu]

On 01 Oct 2000 11:59:00 +0200, Martin von Loewis
<loewis at informatik.hu-berlin.de> wrote: 

>Computing a+a will first invoke __coerce__. Since that is not defined,
>it will invoke __getattr__ - this is what happens. Defining __coerce__
>would fix this problem.
>

Thanks for this info.  It seems that

    def __coerce__(self, other): return self, other

works and cut the overhead by at least half. 

However, I'm not sure how is __coerce__ supposed to work.  The documentation
has just a very terse description:

coerce (x, y) 
      Return a tuple consisting of the two numeric arguments converted to a
      common type, using the same rules as used by arithmetic operations.

Does this mean

    a+b == apply(a.__class__.__add__, a.__coerce__(b))

None of my three books mention coerce.

Huaiyu