On 3/19/2010 4:25 AM, Arnaud Delobelle wrote:
On 19 Mar 2010, at 03:43, Scott Dial <scott+python-ideas@scottdial.com> wrote:
Which is to say, I would be more amenable to adding such a feature if it was building closure. And in that usage, it would seem to be more generally useful and well-behaved.. outsiders don't normally modify closures (if you want this sort of interface, you probably should define a class).. it allows you to avoid naming the function in the function.. and it is a much closer substitute for the default arguments kludge that is so commonly abused.
Why not just use default arguments?
My problem with this particular kludge is that rarely are these arguments meaningful as *arguments*. They become a part of the function definition that shows up in documentation. Worse to me is that the keyword names block those names from appearing in **kwds, which is problematic for creating a transparent function (e.g., when writing a decorator that takes an unknown set of keyword arguments) and evokes dynamic-scoping madness. Additionally, they are a source of subtle errors when extra arguments are passed to functions (although this is mitigated mostly by Py3's keyword-only arguments syntax). All of those problems go away with a magical @closure() decorator, but I realize that creating such a decorator would be quite a kludge in-and-of-itself. Perhaps it's a bit too clever. -- Scott Dial scott@scottdial.com scodial@cs.indiana.edu