overloading *something

[Alex Martelli]

Ron Adam <rrr at ronadam.com> wrote:

> James Stroud wrote:
> 
> > Hello All,
> > 
> > How does one make an arbitrary class (e.g. class myclass(object)) behave
> > like a list in method calls with the "*something" operator? What I mean
> > is:
> 
> You need to base myclass on a list if I understand your question.

Not necessary, all you need is __iter__:

>>> def f(*a): print a
... 
>>> class X(object):
...   def __iter__(self): return iter(xrange(4))
... 
>>> f(*X())
(0, 1, 2, 3)
>>> 

> > I've looked at getitem, getslice, and iter. What is it if not one of these?

Obviously James hadn't looked at __iter__ in the RIGHT way!


> > And, how about the "**something" operator?
> > 
> > James
> 
> A dictionary would be pretty much the same except subclassed from a 
> dictionary of course.

I believe this one is correct (but I have not checked in-depth!).


Alex