Re: Differences between -isEqual: and -isEqualTo:?
Re: Differences between -isEqual: and -isEqualTo:?
- Subject: Re: Differences between -isEqual: and -isEqualTo:?
- From: Ken Thomases <email@hidden>
- Date: Thu, 18 Sep 2008 17:21:45 -0500
On Sep 18, 2008, at 5:15 PM, Charles Srstka wrote:
On Sep 18, 2008, at 4:59 PM, Dave DeLong wrote:
IIRC, isEqual: compares memory addresses, whereas isEqualTo:
compares hashes of the objects being compared. I also believe that
isEqual: is the preferred method.
The documentation says that isEqual: checks the hashes, so that
isn't it.
No, it doesn't. It says that if two objects compare equal, then they
must have the same hash. This is a not for overriders of -isEqual: to
make sure they know that they have to implement a corresponding -hash
that maintains this invariant rule.
Cheers,
Ken
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