Mailing Lists: Apple Mailing Lists
Image of Mac OS face in stamp
 
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: The problem with bindings

Thank you for bringing this discussion to cocoa-dev; I have participated in many similar discussions and have found myself defending my intelligence and understanding rather than discussing how this technology might be improved. Its unfortunately part of our community: because you understand a technology, are certainly capable of using this technology, and have some concerns, means that you are less than a forceful wave of programmers who happily use this technology for its functionality.

I have discussed many things: bindings, NSDocument, NSWindowController, NSTableView, and others. These technologies have true functionality, but as a community we seem to value functionality greater than design (and always seem to value compatibility greater than either consistency or design).

I'm no bindings layer expert, but the little time I have spent using them, I have found them quite difficult to grasp. Much more so than the outlet-target approach.

Yes. When I was more involved with supporting InterfaceBuilder, I saw many beginners scratch their heads a few times before undestanding target/action, outlets, and how these patterns connected to and affected their code. Bindings are far more difficult to understand partly because they are less tangible: outlets ivars written into your header file and prefixed with IBOutlet, target is simply an IBOutlet that is connected along with an action, actions are methods implemented by your targets. Simple.

Bindings are undocumented (except by their listing in IB) identifiers with undocumented (but sometimes/often implied) behavior that will often trigger further undocumented but useful behavior and sometimes other bindings.

I usually find that if things go well with bindings, I really can save that '300 lines of code' that everyone talks about,

Anything that a programmer does should be considered similar to lines of code; bindings need to be "written", maintained, debugged, and maybe localized just like code, so sometimes saving lines of code isn't really saving lines of code.

There are also secondary advantages to code: breakpoints work within code, code can be copy/pasted, object reuse by nib instantiation is often easier than reestablishing a set of bindings, outlets/actions can be added to objects without writing an IB palette, code completion and compile time checking can make typing identifiers easier and more reliable. Also, code can be more flexible (or can adapt more simply) to handle subtle problems (a defaults controller has difficulty pulling a single value from within an array). A need for code based solutions can introduce inconsistencies: consider drag/drop and other table view problems: data source api, delegate api, bindings, and NSArrayController all combine to make a solution that feels self inconsistent (converting between rows as an array of NSNumber objects and rows as an NSIndexSet).

but when things go wrong, I can spend hours tracking down the problems, effectively negating any benefit I may have gained. Furthermore, easy things, like populating a table view with values, are well documented, and can be achieved very efficiently with bindings.

Technology introduced along with bindings makes writing a data source that fills a table view very efficient (about 10 lines of code to display single values and allow sorting). NSArrayController does so much more that when we want to go further than these 10 lines of code, NSArrayController becomes interesting.

None of these advantages to code make bindings useless; bindings have true functionality that can't be matched by each individual programmer writing their own solutions. But, we should try to understand bindings while also trying to understand code based alternatives. Is there a better solution? a better investment for Apple's time? maybe, but it doesn't really matter: we have bindings (they aren't going away) and Apple's time is already spent.


-jim
_______________________________________________
cocoa-dev mailing list | email@hidden
Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/cocoa-dev
Do not post admin requests to the list. They will be ignored.

References: 
 >The problem with bindings (From: Drew McCormack <email@hidden>)



Visit the Apple Store online or at retail locations.
1-800-MY-APPLE

Contact Apple | Terms of Use | Privacy Policy

Copyright © 2007 Apple Inc. All rights reserved.