[Python-Dev] TypeError: f() missing 1 required positional argument: 'x'

Benjamin Peterson benjamin at python.org
Thu Sep 20 16:12:04 CEST 2012

2012/9/20 Mark Dickinson <dickinsm at gmail.com>:
> Thoughts?

I tried to define the error messages in terms of the callee's
signature. I call the formals that are not variadic, keyword variadic,
or keyword-only, positional. For example, in

def f(a, b, c, *args, d):

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).

I'm certainly open to suggestions.


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