[Python-3000] Pronouncement on parameter lists

[Jim Jewett]

On 4/21/06, Alex Martelli <aleaxit at gmail.com> wrote:
> On 4/21/06, Guido van Rossum <guido at python.org> wrote:

> > To prevent more abominations like this, let me pronounce that I now
> > like the single-star syntax:

> >   def foo(a, b, *, x=1, y=2): ...

> So, what will this syntax signify?  If the single-star stands for
> "arbitrary positional arguments", how will the body of foo access
> them?  Sorry if these have been well covered already, but I read back
> through this thread and couldn't find them.

No, *args stands for arbitrary positional arguments.

The unadorned * stands for "anything after this must be passed as a keyword".

It has not yet been specified what would happen to additional
positional arguments that get passed in anyway.  (Swallow or raise an
Exception?)

It has not yet been specified whether the keyword-only arguments must
each have a default.  Most proposals assume not, but then do ugly
things to support that assumption.  The above suggests

    def foo(a, b=2, *, x=3, y=4):   # OK
    def foo(a, b=2, *, x, y=4):      # not yet decided

-jJ