Re: Nil items in NSMutableSet
Re: Nil items in NSMutableSet
- Subject: Re: Nil items in NSMutableSet
- From: Clark Cox <email@hidden>
- Date: Tue, 16 Mar 2010 11:45:08 -0700
On Tue, Mar 16, 2010 at 11:35 AM, Thomas Davie <email@hidden> wrote:
>> Your code doesn't account for the possibility that the order of
>> comparison might happen in the other order (i.e. [@"123" isEqual:
>> object]). I wouldn't be surprised if NSSet is assuming that equality
>> is transitive (i.e. [a isEqual: b] == [b isEqual: a]).
>
> For reference, this property is not transitivity, the transitivity relation is:
>
> a -> b ^ b -> c => a -> c (for some relation ->)
>
> The one you're looking for is commutativity.
Indeed; must have been echos of my previous life as a C++ programmer
creeping into the Obj-C part of my brain (in C++, the std::set class
uses less than, instead of equality, where transitivity is the
important property, not commutativity).
:)
--
Clark S. Cox III
email@hidden
_______________________________________________
Cocoa-dev mailing list (email@hidden)
Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden