[Tim] >> And I'll take this opportunity to repeat the key point for me: I >> tried hard, but never found a single case based on staring at real >> code where allowing _fancier_ (than "plain name") targets would be a >> real improvement. In every case I thought it _might_ help, it turned >> out that it really didn't unless Python _also_ grew an analog to C's >> "comma operator" (take only the last result from a sequence of >> expressions). I'll also note that I asked if anyone else had a >> real-life example, and got no responses.
[MRAB <pyt...@mrabarnett.plus.com>] > Could a semicolon in a parenthesised expression be an equivalent to C's > "comma operator"? I expect it could, but I it's been many years since I tried hacking Python's grammar, and I wouldn't want a comma operator anyway ;-) To recycle a recently-posted example, instead of one of these 3: if ((a, b, c) := func_returning_triple()) and b > 0: process(a+b, b+c, a+c) if ((a, b, c) := func_returning_triple()) > 0: .... if [((a, b, c) := func_returning_triple()), b > 0][-1]:: ... it would allow this instead: if ((a, b, c) := func_returning_triple(); b > 0): ... That's better than any of the first three, but I'm not sure it's better than the original a, b, c = func_returning_triple() if b > 0: ... It _may_ be more readable in other complex-target examples, though. It's also what's wanted in one of the running plain-name target examples, _not_ involving a conditional context: r1, r2 = (D := sqrt(b**-4*a*c); a2 := 2*a; ((-b+D)/a2), (-b-D)/a2)) And if I saw enough code like that, I'd write a PEP suggesting that Python introduce separate assignment statements where name bindings persisted across statement boundaries ;-) _______________________________________________ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com