[Python-Dev] Change to yield-from implementation

[Greg Ewing]

Mark Shannon wrote:

> We have recently removed the f_yieldfrom field from the frame object.
> (http://bugs.python.org/issue14230)

Hey, wait a minute. Did anyone consider the performance effect
of that change on deeply nested yield-froms?

The way it was, a yield-from chain was traversed by a very
tight C loop that found the end frame and resumed it directly.
If I understand what you've done correctly, now it has to
enter and execute a bytecode in every frame along the way.

-- 
Greg