[Python-ideas] Positional only arguments

[Steven Bethard]

On 5/18/07, Talin <talin at acm.org> wrote:
> Steven Bethard wrote:
> > Not sure I understand the question. My point was only that you'll
> > never reproduce this behavior::
> >
> >     >>> dict(self=1, other=2)
> >     {'self': 1, 'other': 2}
> >     >>> d = {}
> >     >>> d.update(container=2, sequence=1)
> >     >>> d
> >     {'container': 2, 'sequence': 1}
> >
> > Of course, you can rename the 'self' and 'container' parameters to
> > something else, but that just means that you can't use whatever new
> > names you choose. The only way to solve this is to use real
> > positional-only arguments, which currently means using *args and
> > parsing out things within the function body.
>
> I would just use names beginning with an underscore, or some other
> convention that is unlikely to occur as a dict key.

So should I take that as a +1 for:

* Enforce double-underscore names as being positional-only syntactically, e.g.::

   def f(__a, __b=None, *, c=42, **kwargs)

 Pro: requires no new syntax
 Con: slightly backwards incompatible (but who calls f(__a) anyway?)

STeVe
-- 
I'm not *in*-sane. Indeed, I am so far *out* of sane that you appear a
tiny blip on the distant coast of sanity.
        --- Bucky Katt, Get Fuzzy