Greg Ewing writes:
> Consider this:
>
> def g():
> return ((yield i) for i in range(10))
>
> Presumably the yield should turn g into a generator, but...
> then what? My brain is hurting trying to figure out what
> it should do.
I don't understand why you presume that. The generator expression
doesn't do that anywhere else. My model is that implicitly the
generator expression is creating a function that becomes a generator
factory, which is implicitly called to return the iterable generator
object, which contains the yield. Because the call takes place
implicitly = at compile time, all the containing function "sees" is an
iterable (which happens to be a generator object). "Look Ma, no
yields left!" And then g returns the generator object.
What am I missing?
In other words, g above is equivalent to
def g():
def _g():
for i in range(10):
# the outer yield is the usual implicit yield from the
# expansion of the generator expression, and the inner
# yield is explicit in your code.
yield (yield i)
return _g()
(modulo some issues of leaking identifiers). I have not figured out
why either your g or my g does what it does, but they do the same
thing.
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