[Python-ideas] Keyword-only arguments?

Todd toddrjen at gmail.com
Wed Jun 17 21:01:20 CEST 2015

On Jun 17, 2015 8:58 PM, "Amber Yust" <amber.yust at gmail.com> wrote:
> One thing that has been a source of bugs and frustration in the past is
the inability to designate a named keyword argument that cannot be passed
as a positional argument (short of **kwargs and then keying into the dict
directly). Has there been any previous discussion on the possibility of a
means to designate named arguments as explicitly non-positional?
> Not a solid proposal, but to capture the essential difference of what I'm
thinking of, along the lines of...
>     def foo(bar, baz=None, qux: None):
> where bar is a required positional argument, baz is an optional argument
that can have a value passed positionally or by name, and qux is an
optional argument that must always be passed by keyword.
> Such a means would help avoid cases where a misremembered function
signature results in a subtle and likely unnoticed bug due to unintended
parameter/argument mismatch.
> (It's possible that this has been discussed before - a cursory search of
python-ideas didn't bring up any direct discussion, but I may have missed
something. If you have a link to prior discussion, please by all means
point me at it!)

Already present in python 3:

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