On 11/22/2014 12:30 PM, Raymond Hettinger wrote:
Pre-PEP 479:
-----------
> def middleware_generator(source_generator):
> it = source_generator()
> input_value = next(it)
> output_value = do_something_interesting(input_value)
> yield output_value
Post-PEP 479:
------------
> def middleware_generator(source_generator):
> it = source_generator()
> try:
> input_value = next(it)
> except StopIteration:
> return # This causes StopIteration to be reraised
> output_value = do_something_interesting(input_value)
> yield output_value
While I am in favor of PEP 479, and I have to agree with Raymond that this
isn't pretty.
Currently, next() accepts an argument of what to return if the iterator is
empty. Can we enhance that in some way so
that the overall previous behavior could be retained?
Something like:
def middleware_generator(source_generator):
it = source_generator()
input_value = next(it, gen_exit=True) # or exc_type=GeneratorExit ?
output_value = do_something_interesting(input_value)
yield output_value
Then, if the iterator is empty, instead of raising StopIteration, or returning
some value that would then have to be
checked, it could raise some other exception that is understood to be normal
generator termination.
--
~Ethan~
signature.asc
Description: OpenPGP digital signature
_______________________________________________ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
