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. You're right to be cautious. My understanding of PEP 505 is that #13. a ?. b ?. __str__ #14. (a ?. b) ?. __str__ are not equivalent. The first is None, and the other is None.__str__. That looks like a gotcha. (By the way, it was not my intention to catch you out. I'm simply looking for clarity. I wasn't aware of the gotcha until I started answering myself the question I had asked you.) However, the None object is somewhat special, in that all it's methods and double-under (dunder) methods. And one of them is __bool__. And we can't add or change the attributes of None. Chris, you don't have to reply to this. But I would be pleased if an expert could either tell me that my neck is safe, or produce a value of 'a' that cuts it off (so to speak). -- Jonathan