On or about 6/2/10 11:11 AM, thus spake "Greg Parker" <gpar...@apple.com>:
> On Jun 2, 2010, at 8:57 AM, Matt Neuburg wrote: >> So this appears to be a technique for implementing a highly informal >> protocol. (The technique is: define a protocol, don't bother adopting it >> anywhere, but send messages defined in that protocol to an id.) > > Yep. When the compiler looks for a method declaration matching a message sent > to `id`, it looks at every declaration encountered up to that point in the > file. > > That's comparable to the traditional way to create informal protocols: declare > a category on NSObject, don't bother implementing it anywhere, and send > messages declared in that category to other objects. > > In general we discourage both of these now. But in fact I see now that UIAlertView works exactly this way; its delegate is typed as id, not as id <UIAlertViewDelegate>. This explains why my class never has to adopt UIAlertViewDelegate formally. Doubtless an alert view with a delegate is *so* common that Apple felt it would drive the programmer mad to have to adopt UIAlertViewDelegate formally all over the place. m. -- matt neuburg, phd = m...@tidbits.com, http://www.tidbits.com/matt/ pantes anthropoi tou eidenai oregontai phusei Among the 2007 MacTech Top 25, http://tinyurl.com/2rh4pf AppleScript: the Definitive Guide, 2nd edition http://www.tidbits.com/matt/default.html#applescriptthings Take Control of Exploring & Customizing Snow Leopard http://tinyurl.com/kufyy8 RubyFrontier! http://www.apeth.com/RubyFrontierDocs/default.html TidBITS, Mac news and reviews since 1990, http://www.tidbits.com _______________________________________________ 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
