[Python-Dev] PEP 380 (yield from a subgenerator) comments

[Ron Adam]

P.J. Eby wrote:

> Sure.  But right now, the return value of a generator function *is the 
> generator*.  And you're free to ignore that, sure.
> 
> But this is a "second" return value that only goes to a special place 
> with special syntax -- without that syntax, you can't access it.
> 
> But in the use cases where you'd actually want to make such a function 
> return a value to begin with, it's because that value is the value you 
> *really* want from the function -- the only reason it's a generator is 
> because it needs to be paused and resumed along the way to getting that 
> return value.


How about if 'yield from' returns the generator object, and the return 
value is accessed with an attribute.

    g = yield from gen
    x = g.__value__

Or

    x = (yield from gen).__value__



Another possibility is to be able to break from a 'yield from' at some 
point and then continue it to get any final values.

    # yield values of sub generator
    g = yield from gen

    # get remaining unused value of sub generator
    x = g.next()