On Thu, Sep 20, 2012 at 7:12 AM, Benjamin Peterson benjamin@python.org wrote:
def f(a, b, c, *args, d): pass
a, b, and c are positional. Hence the "positional" in error messages.
As you noted in your next message, keyword-only arguments need to be distinguished from these "positional" arguments somehow. Maybe it helps to think of "positional" to mean "the only formals you can pass to with position" (excepting variadic ones).
That is how I think of "positional".
However, the other wrinkle is that some arguments really are "position-only," for example:
len(s="abc")
Traceback (most recent call last): ... TypeError: len() takes no keyword arguments
I think it is a defect of our documentation that we don't have a way to distinguish between "positional" and "position-only" arguments in the function signature notation we use in our documentation, leading to issues like this one:
"accept keyword arguments on most base type methods and builtins":
http://bugs.python.org/issue8706
--Chris