On Tue, Dec 15, 2020 at 9:22 PM Paul Sokolovsky <pmis...@gmail.com> wrote: > On Tue, 15 Dec 2020 20:17:37 +1100 > Chris Angelico <ros...@gmail.com> wrote: > > > On Tue, Dec 15, 2020 at 8:04 PM Paul Sokolovsky <pmis...@gmail.com> > > wrote: > > > So, let's try simple yes/no questions: > > > > > > Example 1: > > > > > > a + b + c vs a + (b + c) > > > > > > Question 1: > > > Do you agree that there's a clear difference between left and right > > > expression? Yes/no. > > > > Yes, there is a difference. > > > > > Example 2: > > > > > > a.b() vs (a.b)() > > > > > > Question 2: > > > Do you agree that there's a *similar* difference here as in Example > > > 1? Yes/no. > > > > No, there is no difference. > > > > > > > > Then of course depending on the outcome of the last question, there > > > would be further questions. Specifically: > > > > > > If yes: How to put a solid formal basis behind the difference in > > > Example 2 (because so far we're just riding on the similarity with > > > Example 1). And how to explain it to wider audience? > > > > > > > Uhh, it's called precedence and associativity? You know that (a + b + > > c) is equivalent to ((a + b) + c), not to (a + (b + c)). Is that > > formal enough? > > Yes. But you answered "no" to the Example 2. What makes you think that > (a + b + c) is not equivalent to (a + (b + c)), but (a.b()) is > equivalent to ((a.b)()), that's what I'm asking. >
Precedence and associativity? Since the two operators have the same precedence (in this case it's the same operator twice), order of evaluation is defined by its left-to-right associativity. Seriously, are you actually unaware of this fundamental, or are you playing dumb to try to make a point? I'm still trying to figure out your point here. The parentheses in one example are changing order of evaluation. In the other, they're not. I do not understand why this is even a question. I'm pretty sure most of us learned *in grade school* about BOMDAS or BODMAS or PEMDAS or whatever mnemonic you pick. Or maybe you have to wait till high school to learn that exponentiation is right-to-left associative. Either way, it's not new knowledge to most programmers. I'm done arguing, unless you actually come up with a real argument. ChrisA _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/TIYWNVD2ZKQIZTDYPVAMGNLK4TXV5HX3/ Code of Conduct: http://python.org/psf/codeofconduct/
