On Tue, Mar 16, 2010 at 2:18 PM, Alejandro Rodriguez <[email protected]> wrote: > You were right, my equality is not transitive. > > id ob = [[objectClass alloc] initWithId:@"hello"]; > [ob isEqual:@"hello"]; //returns YES > [@"hello" isEqual:ob]; //returns NO > > That may very well be the problem... now... I have no idea on how I will make > the second test return YES.
I doubt that you can. You'll likely have to give up on the idea of being able to pass a string to -member:. You could implement the check in a method of your own in a category on NSSet. > doesn't that depend on the implementation of isEqual of the asking object in > this case NSString? Yes. > Have any of you had to deal with this before? I'll dive into the docs and see > what details I find that might be useful. > > Seems we are getting somewhere > cheers! > > Alejandro > > On Mar 16, 2010, at 2:45 PM, Clark Cox wrote: > >> On Tue, Mar 16, 2010 at 11:35 AM, Thomas Davie <[email protected]> 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 protected] > > -- Clark S. Cox III [email protected] _______________________________________________ Cocoa-dev mailing list ([email protected]) 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: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to [email protected]
