On 3/8/18 1:00 AM, Nick Sabalausky (Abscissa) wrote:
On 03/08/2018 12:05 AM, ketmar wrote:
Nick Sabalausky (Abscissa) wrote:
I'm having trouble finding the documentation for what exactly the
unary "not" operator does when applied to a class/interface object.
Does this documentation exist somewhere?
I know at least part of it involves "is null", but I seem to remember
hearing there was more to it than just that.
https://dlang.org/spec/operatoroverloading.html#boolean_operators
"Class references are converted to bool by checking to see if the
class reference is null or not."
Ah, thanks.
But are we CERTAIN that's all there is to it? I have a non-reduced
situation right now where outputting the address of a class reveals a
non-null address, and yet assert(!!theObjectInQuestion) is failing.
(this is occurring during stack unwinding, if that makes a difference)
One thing to keep in mind, assert(someObject) does more than just check
if it's not null, it also runs the object's invariant to see if it's valid.
I'm not sure about assert(!!someObject), probably this is just checking
for non-null, but I'm not sure if the compiler folds this into
assert(someObject) (which would be a bug, but may explain things). To be
more pedantic, I'd recommend assert(someObject !is null)
-Steve
