On 25 April 2018 at 00:54, Eric Snow <[email protected]> wrote: > Regardless, your 3 rules would benefit either syntax. Nick may have a > point that the rules might be an excessive burden, but I don't think > it's too big a deal since the restrictions are few (and align with the > most likely usage) and are limited to syntax so the compiler will be > quick to point mistakes.
I think the "single name target only" rule should be in place no matter the syntax for the name binding operator itself. I don't mind too much either way on the mandatory parentheses question (it's certainly an easy option to actively discourage use of binding expressions as a direct alternative to assignment statements, but as with the single-name-only rule, it's independent of the choice of syntax) I *do* think the "no name rebinding except in a while loop header" restriction would be annoying for the if/elif use case and the while use case: while (item = get_item()) is not first_delimiter: # First processing loop while (item = get_item()) is not second_delimiter: # Second processing loop # etc... if (target = get_first_candidate()) is not None: ... elif (target = get_second_candidate()) is not None: ... elif (target = get_third_candidate()) is not None: ... And *that* rule is unique to the "=" spelling, since for other proposals "lhs = rhs" in an expression is *always* a syntax error, and you have to resolve the ambiguity in intent explicitly by either adding a second "=" (to request equality comparison), or else some other leading symbol (to request a binding expression). Cheers, Nick. -- Nick Coghlan | [email protected] | Brisbane, Australia _______________________________________________ Python-Dev mailing list [email protected] https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com