On 04/25/2018 03:15 PM, Ethan Furman wrote:
On 04/25/2018 02:55 PM, Tim Peters wrote:
This becomes a question of seasoned judgment. For example, here's a real loop summing a series expansion, until the new terms become so small they make no difference to the running total (a common enough pattern in code slinging floats or decimals):
while True: old = total total += term if old == total: return total term *= mx2 / (i*(i+1)) i += 2
To my eyes, this is genuinely harder to follow, despite its relative brevity:
while total != (total := total + term): term *= mx2 / (i*(i+1)) i += 2 return total
So I wouldn't use binding expressions in that case. I don't have a compelling head argument for _why_ I find the latter spelling harder to follow, but I don't need a theory to know that I in fact do.
I know why I do: I see "while total != total" and my gears start stripping. On the other hand,
while total != (total + term as total): ...
I find still intelligible. (Yes, I know "as" is dead, just wanted to throw that out there.)
Having said that, since whomever mentioned reading ":=" as "which is", I'm good with ":=".