Is that possible to have a new feature: dynamic return with using function argument

[kouui]

In python 3.8, we will have a new syntax := that could assign values to variables as part of larger expression, for example,

if (n:=len(a)) > 10:
    ....

On the other hand, I also think that it would be useful if := could be used in function argument, so that a local variable created inside a function could be returned **optionally**, for example,

def func(arg1, arg2, karg1=karg1_default, karg_return:=karg_return):
    
    ...
    karg_return = 3
    ...
    
    return func_output

# normal calling of func() without returning variable karg_return
# in this way, karg_return:=karg_return is not used and karg_return is only simply a local variable in func()
output = func(2,3,karg1=4)

# calling func() with using the karg_return argument
# in this way, value of the local variable karg_return in func() is created and "passed" to variable a
output = func(2,3,karg1=4,a:=karg_return)
print(a) # a = 3

Is that possible to have this new feature in new python version?

[ThomasL]

I don´t know, as this is not our decision to make.
If you think this would be a nice feature in future python you can propose this
to Python developers https://www.python.org/dev/peps/
If your idea is good they will think about it.

[kouui]

@ThomasL
Thanks a lot. I will post my proposal to PEPs.