Re: Problem with +numberWithBool: ?

[Richard Frith-Macdonald]

On 29 Jan 2004, at 12:24, Manuel Guesdon wrote:

> Hi,
>
> +numberWithBool: is defined as:
>
>         + (NSNumber*) numberWithBool: (BOOL)value
>         {
>           if (value == YES)
>             {
>               return boolY;
>             }
>           else
>             {
>               return boolN;
>             }
>         }
>
> So as far as I understand [NSNumber numberWIthBool:2] will return 
> boolN which is wrong as 2 is TRUE, isn't it ? (Or may
> I need some sleep ? :-)

I agree it'll return boolN ... but 2 is not YES
Booleans in objc can be YES or NO ... this is not the same thing as 
true/false in C/ObjC conditionals where 0 is false and anything 
non-zero is true.
So ...

if (x)...
is not the same as
if (x == YES)
where x is of type BOOL

which is why I prefer to write code which explicitly compares booleans 
values with YES or NO.

> I suggest:
>         + (NSNumber*) numberWithBool: (BOOL)value
>         {
>           if (value == NO) // NO is always 0 but YES is a value != 0
>             {
>               return boolN;
>             }
>           else
>             {
>               return boolY;
>             }
>         }

I think it might be better to raise an exception if value is not YES or 
NO