[Python-ideas] The async API of the future: yield-from

Nick Coghlan ncoghlan at gmail.com
Mon Oct 15 15:48:46 CEST 2012

On Mon, Oct 15, 2012 at 10:31 PM, Calvin Spealman <ironfroggy at gmail.com> wrote:
> Currently, "with yield expr:" is not valid syntax, surprisingly.

It's not that surprising, it's the general requirement that yield
expressions must be enclosed in parentheses except when used
standalone or in a simple assignment statement.

"with (yield expr):" is valid syntax though, so I'm reluctant to
endorse doing anything substantially different if the parentheses are

I think the combination of "yield from" to delegate control (including
exception handling) completely to a subgenerator and "context manager
+ for loop + explicit yield" when an operation needs to yield multiple
times and the exception handling behaviour should be left to the
caller (as in the "as_completed" case) should cover the necessary


Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia

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