[Python-Dev] Very Strange Argument Handling Behavior

[Guido van Rossum]

On Sat, Apr 17, 2010 at 9:22 AM, Nick Coghlan <ncoghlan at gmail.com> wrote:
> Guido van Rossum wrote:
>> Because Python promises that the object the callee sees as 'kwargs' is
>> "just a dict".
>
> Huh, I thought kwargs was allowed to be implemented as a
> string-keys-only dict (similar to class and module namespaces) while
> still be a valid Python implementation. I guess I was wrong.

Actually I don't know about that. Is there language anywhere in the
language reference that says this? What do IronPython, Jython, PyPy
actually do?

In any case my line of reasoning in this case isn't affected by this;
as I pointed out in my reply to Steve, the relation between the **k
passed in by the caller and the **k received by the callee is less
direct than you might think. The proposed change *only* affects the
dict() builtin; any change in the type of **k seen by the callee would
potentially affect all user-defined functions.

-- 
--Guido van Rossum (python.org/~guido)