On Sunday, 29 October 2017 at 18:02:25 UTC, Jonathan M Davis
wrote:
On Sunday, October 29, 2017 17:35:25 Nemanja Boric via
Digitalmars-d wrote:
On Sunday, 29 October 2017 at 17:19:44 UTC, Jonathan M Davis
wrote:
> On Sunday, October 29, 2017 16:44:39 Ola Fosheim Grøstad via
>
> Digitalmars-d wrote:
>> On Sunday, 29 October 2017 at 16:29:57 UTC, Jonathan M Davis
>>
>> wrote:
>> > valid using ?:, I would think that you'd want to be doing
>> > the same check with stuff like if statements anyway. So,
>> > it sounds to me like overloading opCast!bool would work
>> > just fine.
>>
>> If you try to do:
>>
>> some_float ?: 0.0
>>
>> then it will do nothing as cast(bool)std.math.NaN(0) => true
>
> NaN is supposed to always be false.
OT, but I had to :-)
```
void main()
{
import std.stdio;
float x;
x? writeln("Oh no, a NaN!") : writeln("All good.");
}
```
Same happens for assert(float.nan) - it doesn't fail.
Sounds like a bug to me. NaN is supposed to be false whenever
it's used in a comparison. If it it's true when cast directly
to bool, then that's inconsistent.
- Jonathan M Davis
We've already reported this as a bug (I actually got quite burned
on it, trusting assert(float_value) to prevent NaN's escaping the
function), but there were different opinions on this, so it never
got anywhere: https://issues.dlang.org/show_bug.cgi?id=13489
