[Python-Dev] PEP 3102: Keyword-only arguments

[Edward Loper]

Fred L. Drake, Jr. wrote:
> On Sunday 30 April 2006 22:50, Edward Loper wrote:
>  > I see two possible reasons:
> 
> Another use case, observed in the wild:
> 
>    - An library function is written to take an arbitrary number of
>      positional arguments using *args syntax.  The library is released,
>      presumably creating dependencies on the specific signature of the
>      function.  In a subsequent version of the function, the function is
>      determined to need additional information.  The only way to add an
>      argument is to use a keyword for which there is no positional
>      equivalent.

This falls under the "first subproposal" from Terry's email:

> There are two subproposals: first, keyword-only args after a variable 
> number of positional args, which requires allowing keyword parameter 
> specifications after the *args parameter, and second, keyword-only args 
> after a fixed number number of positional args, implemented with a naked 
> '*'.  To the first, I said "The rationale for this is pretty obvious.".  To 
> the second, I asked, and still ask, "Why?".

I was trying to come up with use cases for the "second subproposal."

-Edward