On Tue, Oct 20, 2020 at 04:26:16PM -0700, Guido van Rossum wrote:
> So this would break many uses of locals(). I'm not sure I like that.
That's a good point I didn't think of.
We could rescue the concept by saying that any reference to locals()
inside the function disables the elimination, but of course locals can
be shadowed or aliased, and we can't expect the interpreter to do a full
analysis of the entire program.
# Module A
wibble = locals
# Module B
from A import wibble # this is actually locals
def func():
_a = 1
return wibble()
I think that if there was a big performance gain from elimination, we
could chalk this up to consenting adults and just say "Don't do anything
weird!" but if the performance gain is marginal, it probably isn't worth
the hassle.
On the third hand, and far more speculative, if we had a way of giving
compiler directives, we could make these sorts of optimizations opt-in
or opt-out on a fine-grained basis.
--
Steve
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