Project Elvis

[Ola Fosheim Grøstad]

On Sunday, 29 October 2017 at 20:37:21 UTC, bauss wrote:
> But casting to bool is what you use to tell whether something 
> is valid or not.
>
> true = valid, false = invalid.


Not really. In mathematics 0 and 1 can be considered as "true" 
and "false" for a 2-value calculus, while you might reserve ⊤ and 
⊥ for true and false in the logic you use to reason about that 
calculus.

Which is why some languages assumes an equality between 0 and 
true and 1 and false, but that does not by necessity suggest 
valid/invalid.

On the other hand. For things like Unix function call return 
values -1 is often used to signify an invalid result, and 0 does 
not signify failure.

So if you want strict typing, you have to do something else. 
Because C  (and thus D) takes the mathematical view on the 
relationship between integers and bools and propagate that view 
to all other basic types (e.g. floats).


Ola.