Hi Rhodri
You wrote:
>This, by the way, is why think using the same syntax for function definition
>and generator definition was a mistake. It's only when I reach a "yield"
>statement that I realise my expectations for this code are wrong.
Here's something that might help, and surprise, you. This has been
present since Python 2.5.
>>> def fn():
... if None:
... yield
...
>>> list(fn()) # Fails, unless fn is a generator function.
[]
I think what's happening is this. Even though the None-guarded yield
has been optimised away, it leaves a residue. Namely, that there's a
yield in the function. Hence fn() is an iterator.
Having explained the surprise, here's how it can help you. Suppose you
have a long function body, with a single yield at the bottom. If you
write like this:
def my_very_long_function_with_one_yield_point(...):
if None: yield # This is a generator function.
then the next programmer can know immediately that it's a generator function.
--
Jonathan
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