On 8/7/18 3:18 PM, JN wrote:
int a, b;
if (a = 3) { } <- not allowed: Error: assignment cannot be used as a
condition, perhaps == was meant?
b = a = 3 ? 4 : 5 <- allowed
I believe the second case should be disallowed also. It seems illogical,
that the first one isn't allowed, but the second one is, when the second
one is also 'assignment used as condition'. Is there a valid usecase for
such assignment?
But operator precedence says that this is really:
b = (a = (3 ? 4 : 5))
It's a different thing than the if statement. In the if statement, it's
the *assignment* that is now the condition. Here, it is not an
assignment that is the condition, but `3`. There is no common error that
requires preventing assignment from the result of an assignment.
I realize that what you seeing is a typo from:
b = a == 3 ? 4 : 5
but the problem is that you are relying on precedence incorrectly here.
If you type:
b = (a = 3) ? 4 : 5
Then you get the error. D can't solve all the problems. Best thing to do
is to use parentheses to clarify what you want for your condition rather
than rely on default order of operations.
-Steve
