On Tue, Aug 22, 2017 at 12:44 AM, Yury Selivanov <yselivanov...@gmail.com> wrote:
> On Mon, Aug 21, 2017 at 5:39 PM, Koos Zevenhoven <k7ho...@gmail.com> > wrote: > [..] > >> In the current version of the PEP, generators are initialized with an > >> empty LogicalContext. When they are being iterated (started or > >> resumed), their LogicalContext is pushed to the EC. When the > >> iteration is stopped (or paused), they pop their LC from the EC. > >> > > > > Another quick one before I go: Do we really need to push and pop a LC on > > each next() call, even if it most likely will never be touched? > > Yes, otherwise it will be hard to maintain the consistency of the stack. > > There will be an optimization: if the LC is empty, we will push NULL > to the stack, thus avoiding the cost of allocating an object. > > But if LCs are immutable, there needs to be only one empty-LC instance. That would avoid special-casing NULL in code. -- Koos > I measured the overhead -- generators will become 0.5-1% slower in > microbenchmarks, but only when they do pretty much nothing. If a > generator contains more Python code than a bare "yield" expression, > the overhead will be harder to detect. -- + Koos Zevenhoven + http://twitter.com/k7hoven +
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