On Wed, Aug 1, 2018 at 7:09 PM, Jonathan Fine <jfine2358@gmail.com> wrote:
Hi Chris
We're discussing.
10) a ?. b ?. c 11) (a ?. b) ?. c
I asked
So, are there any values of 'a' for which #10 and #11 don't give the same result?
You replied
I'm not prepared to put my neck out and say "They are absolutely identical" and have people jump on me with some technicality. What is your point here?
I am willing to put my neck out and say a.b.c and (a.b).c are equivalent. And my understanding for PEP 505 is that #10 and #11 is that they are equivalent.
The first pair are easily proven, since we can just probe existing code.
import dis dis.dis(lambda a: a.b.c) 1 0 LOAD_FAST 0 (a) 2 LOAD_ATTR 0 (b) 4 LOAD_ATTR 1 (c) 6 RETURN_VALUE dis.dis(lambda a: (a.b).c) 1 0 LOAD_FAST 0 (a) 2 LOAD_ATTR 0 (b) 4 LOAD_ATTR 1 (c) 6 RETURN_VALUE
Same byte code? Same result. Unless there's a bug in the peephole optimizer or something, which I doubt. ChrisA