On 11 Jan 2010, at 17:01, Jerry Krinock wrote: > > On 2010 Jan 11, at 03:47, Quincey Morris wrote: > >> On Jan 10, 2010, at 19:58, Jerry Krinock wrote: >> >>> toObject:segmentedControl >> >> You *didn't* "bind an NSSegmentedControl to its window controller", you >> actually bound a window controller['s "foo" binding] to [the >> "selectedSegment" property of] a NSSegmentedControl. > > Oops, you're correct. Like the method says, bind:*to*:segmentedControl. > >> IIRC the bindings documentation isn't clear which direction "is bound to" >> refers to and/or it gives the impression that a binding is symmetric (which >> it may effectively be at the level of notifications, but it isn't at the >> level of establishing bindings between objects). > > When I first heard the word "binding", from other uses in English, I assumed > that it was two-way, and labored under this incorrect assumption for quite > awhile. Now I know that a binding is only one way, and further that change > data flows in the *opposite* direction of the *to*. That is, if I bind > myself *to* you, I observe what you do and your changes flow back *to* me. > > I wonder why bindings was not as an extension of KVO, instead of as a > separate sideshow. The effect is the same as KVO, with the addition that a > designated setter is automatically invoked in the observer when a change is > observed.
What makes you say this? Bindings do work by using KVO. The default implementation calls -setValue:forKey: when it detects a change, but any object is free to handle a binding any way it likes. (Most of AppKit as far as I can tell uses a customised process that doesn't retain the target object)._______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) 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 arch...@mail-archive.com
