Re: isEqual: and hash in NSDate

[Markus Hitter]

Am 22.07.2005 um 17:26 schrieb Richard Frith-Macdonald:

> I therefore propose to follow MacOS-X, leaving the implementation  
> of -hash as it is, and changing -isEqual: and -isEqualToDate: to  
> perform exact comparisons.  That allows us to use dates as  
> dictionary keys and gives us MacOS-X compatibility.

This sounds reasonable.

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.


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 and why doesn't NSDate  
simply override -isEqual: instead of introducing -isEqualToDate:?

Is it just an historical artefact? Should I file a bug report at  
Apple to get rid of at least -isEqualTo:?


Markus

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Dipl. Ing. Markus Hitter
http://www.jump-ing.de/