On Wed, Jan 14, 2009 at 11:34 PM, Graham Cox <graham....@bigpond.com> wrote: > If an exception is thrown from somewhere down inside this stack, I'd prefer > it if I could continue to draw what can be drawn, rather than have to abort > the drawing altogether which usually leaves the whole view in a weird state > (at which point I'm hosed - I have to abandon that document and create a new > one, which is hardly user friendly).
This is known as a "continuation". Scheme, for example, often uses them instead of exceptions. Much like a jmp_buf, It contains all of the information necessary to resume execution at the point the continuation is created. In the event of an error, an error handler is invoked with the continuation object, at which point the error handler can inspect the error condition and potentially modify the state such that execution can continue to proceed. It then executes the continuation and the program resumes where it left off. This isn't the model that exceptions follow, unfortunately. By the time your @catch block has caught the exception, the stack has already been unwound and you can't get it back. --Kyle Sluder _______________________________________________ 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
