[Python-ideas] Default arguments in Python - the return - running out of ideas but...

[CTO]

On May 12, 3:56 pm, Pascal Chambon <chambon.pas... at wanadoo.fr> wrote:
> Well, since adding new keywords or operators is very sensitive, and the
> existing ones are rather exhausted, it won't be handy to propose a new
> syntax...
>
> One last idea I might have : what about something like
>
> *    def myfunc(a, b, c = yield []):
>               pass*
>
> I'm not expert in english, but I'd say the following "equivalents" of
> yield (dixit WordWeb) are in a rather good semantic area :
> *Be the cause or source of
> *Give or supply
> *Cause to happen or be responsible for
> *Bring in
>
> Of course the behaviour of this yield is not so close from the one we
> know, but there is no interpretation conflict for the parser, and we
> might quickly get used to it :
> * yield in default argument => reevaluate the expression each time
> * yield in function body => return value and prepare to receive one
>
> How do you people feel about this ?
> Regards,
> Pascal

I'm not a fan. If you thought not reevaluating function expressions
was confusing for newbies, wait until you see what making up a new
kind of yield will do for them.

Why not just push for some decorators that do this to be included in
stdlib? I see the utility, but not the point of adding extra syntax.

>>> @Runtime
... def f(x=a**2+2b+c):
...    return x
...
>>> a = 1
>>> b = 2
>>> c = 3
>>> f()
8

This seems much more intuitive and useful to me than adding new
meanings to yield.

Geremy Condra