Re: [NSDecimalNumber numberWithDouble:x]

[David Ayers]

Manuel Guesdon wrote:
> On 10 Jan 2004 21:00:44 -0700 Adam Fedor <address@hidden> wrote:
>
>  >| On Sat, 2004-01-10 at 07:12, Manuel Guesdon wrote:
>  >| > Hi,
>  >| > 
>  >| > [NSDecimalNumber numberWithDouble:x] retunrs a NSDoubleNumber, not a NSDecimalNumber.
>  >| > Is it correct ? 
>  >| > If yes what is the interest of NSDecimalNumber -initWithDouble: ?
>  >| > Won't it be better to have a NSDecimalNumber -numberWithDouble: ?
>  >| > 
>  >| > And same with for all numberWithXX: ?
>  >| > 
>  >| 
>  >| Yes, NSDecimalNumber probably needs to override all the number methods
>  >| (unless we wanted to put a special check in NSNumber for allocation from
>  >| subclasses).
>
> Have you (or someone) a preference for the method to use ? override or check in 
> numberWithXX:, like the following ?
>
> + (NSNumber*) numberWithDouble: (double)value
> {
>   NSNumber      *theObj;
>         if ([self isKindOfClass:decimalNumberClass])
>                 theObj=[[self alloc]initWithDouble: value];
>         else
>         {
>           theObj= (NSNumber*)NSAllocateObject(doubleNumberClass, 0,
>                     NSDefaultMallocZone());
>                   theObj = [theObj initWithBytes: &value objCType: NULL];
>         }
>   return AUTORELEASE(theObj);
> }
>
> Overriding avoid additional code in NSNumber and avoid slowing it.
Hello,

Acutally I agree with Adam.  NSNumber should allow *any* custom 
subclasses "to do the right thing".  These aren't primiative methods. 
So therefor these look like bugs in the NSNumber implementation to me. 
I think all these numberWith*: methods should test:
if (self == [NSNumber class] || self == [applicableConcreteClass class])
(or rather the cached versions) before executing their current 
implementations using the NSAllocateObject function.  Otherwise it 
should probaly just call [[self alloc] initWith*:] as you have done.

But I haven't dug into it yet...

Cheers,
David