Why do some T.init evaluate to true while others to false?

[Basile B. via Digitalmars-d-learn]

On Thursday, 26 May 2016 at 15:14:21 UTC, Basile B. wrote:
> On Thursday, 26 May 2016 at 15:11:50 UTC, Basile B. wrote:
>> On Thursday, 26 May 2016 at 14:03:16 UTC, ArturG wrote:
>>> [...]
>
>> [...]
>> - integral(*): if (i) <=> if (i > 0)
>
> I obviously meant:
>
> - integral(*): if (i) <=> if (i <> 0)
>
> and "<=>" stands for "equivalence"

I obviously meant:

integral(*): if (i) <=> if (i != 0),

"<>" is the Pascal operator for C's "!=" ....