On 2005-07-22 18:03:38 +0100 Markus Hitter <[EMAIL PROTECTED]> wrote:
Regarding to this, in my little recherche yesterday, I couldn't find any
difference between -isEqual:, -isEqualTo: and -isEqualToDate:. The last
type
is supported by some common other classes as well, e.g. -isEqualToString:,
-isEqualToNumber:, ...
My impression was, -isEqual: is meant for coarse comparisons or hash
comparisons. But that's an impression only.
I don't know of any -isEqualTo: method. AFAIK there is only -isEqual: or
the variants with the class in the name (-isEqualToString:,
-isEqualToNumber: etc)
Since it's interesting for coding in GNUstep/Cocoa as well: Does anybody
know what's the difference between the members of these trios? Why does
-isEqualTo: exist at all
I don't believe it does. At least, not in GNUstep.
and why doesn't NSDate simply override -isEqual:
instead of introducing -isEqualToDate:?
It does override -isEqual:
My understanding is that the variants with the class name in them are
intended as optimisations ... where the method may assume that what it gets
as an argument is a member of the correct class, thus avoiding to need to
check what class the argument belongs to.
Thus, for NSDate, -isEqual: might be implemented as -
- (BOOL) isEqual: (id)anObject
{
if ([anObject isKindOfClass: [NSDate class]])
{
return [self isEqualToDate: (NSDate*)anObject];
}
return NO;
}
Is it just an historical artefact? Should I file a bug report at Apple to
get rid of at least -isEqualTo:?
Maybe ... I don't know about it.
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