> Notice that

> def foo():
>     def myfunc(a, b, c = (yield [])):
>         pass

> already has a meaning in Python.  Under your proposal,

> Anyhow, since you've decided you want add a new kind of default
> argument spelled differently than the standard one, I have to ask what
> this buys you beyond

> def foo():
>     def myfunc(a, b, c = None):
>         if c is not None: # or a setinel
>             c = []

> Sure, it takes two more lines of code to write this (three if you want
> to use an object() instance as your sentinel to allow None being
> passed in), but does not require a new bit of language syntax for
> every Python programmer to learn...

> Greg F

> There's the suggestion that Carl Johnson gave:

>     def myfunc(a, b, c else []):
>         pass

> or there's:

>     def myfunc(a, b, c def []):
>         pass

> where 'def' stands for 'default' (or "defaults to").