2023-08-04 8:18 UTC+02:00, Daniil.arashkevich@gmail.com <Daniil.arashkevich@gmail.com>:
Currently in Python we have construction like this:
tt = 5 while t: # do something tt -= 1
It would be great if in Python we have something like this: tt = 5 while (tt--): # do something
It is exists in C++. And in my opinion it is very Pythonic
Just as a reminder of C/C++: {pre,post}-{inc,dec}rementations bring their lot of issues with the language. Mostly the infamous *undefined behavors*. If you've done some C or C++ this very expression might send shivers down your spine. Assuming a = 0, what's the value of a after: a = a++ ? What's the value of the expression (a++) + (++a) ? What values are passed to the function with: f(a, a++, a) ? I am not sure these would be welcome in python. And allowing such syntax wouldn't feel really pythonic. The worst part is not that the evaluation order is not always defined. It's that even if it were, most people wouldn't remember the rules since they're not obvious from the syntax. I'm not even sure most C programmers know what a "sequence point" is. Some of the backlash about the walrus operator was precisely that it makes the order of evaluation much more important to know in order to understand a program. Assuming a = 0, what does this do: print(a, (a := a + 1), a) ? At least python makes it defined and obvious *when* the side effect occurs... As long as you know that expressions are evaluation left to right. Best regards, Celelibi