Bizarre method keyword-arg bug.

[Jasper]

On Aug 18, 2:40 am, Fredrik Lundh <fred... at pythonware.com> wrote:
> Jasper wrote:
> > Uggg!  /That's/ an intuitive side-effect/wart.  :-/
>
> it's done that way on purpose, of course, because evaluating a full
> closure for each default argument at every call would greatly hurt
> performance (and lead to another set of surprises, of course).
>
> please don't label things that you don't understand and haven't spent
> any time reflecting over as bugs or warts; that's disrespectful to the
> designers and probably not good for your blood pressure.
>
> </F>

I understand it's done that way on purpose, and that there are
tradeoffs
involved, but frankly your /guess/ that I don't understand is wrong.
Having
used Python for some 15 years, I'm hardly a neophyte -- it's pure
serendipity
that this hasn't bitten me before.

I can see the elegance from a language design perspective, the speed
advantage,
etc.  Nonetheless, it's an unintuitive wart, hurting Python's clarity
-- as evidence
I'll point out all the warnings that need to be sprinkled through the
various docs.
And no, the alternative /does not/ have an equivalent set of surprises
-- it's not
like Python is unique in having default arguments.

Frankly, if I wanted speed, I wouldn't be using python, and if I
wanted clever tricks,
I'd use Perl.  Surprise caching as a side-effect is /very/ Perl-like.

-Jasper