On 23 November 2017 at 14:36, Greg Ewing <[email protected]> wrote:
> Paul Moore wrote: > >> 3. List comprehensions are the same as list(the equivalent generator >> expression). >> > > I don't think that's ever been quite true -- there have > always been odd cases such as what happens if you > raise StopIteration in list(generator_expression). > > To my mind, these equivalences have never been intended > as exact descriptions of the semantics, but just a way > of quickly getting across the general idea. Further > words are needed to pin down all the fine details. > Getting the name resolution to be identical was definitely one of my goals when working on the Python 3 comprehension scoping changes. The fact that implicit scopes and yield expressions interact strangely was just a pre-existing oddity from when PEP 342 was first implemented (and one we were able to avoid for async/await by retaining the same "await is only permitted in async comprehensions" constraint that exists for explicit scopes). Cheers, Nick. -- Nick Coghlan | [email protected] | Brisbane, Australia
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