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Rebutting Big Nerd Ranch on Objective-C 2.0 dot notation

The Big Nerd Ranch weblog has a new post about Objective-C 2.0 dot notation. They advocate never using it and they’re completely wrong.

Given my reaction on Twitter, several people have asked me to write a more in-depth rebuttal.

I’ve already addressed when and why you should use Objective-C 2.0 properties and dot notation in an earlier post, so I won’t go into that here. I’ll just repeat my response to their weblog.

Here’s what I wrote in response:

I disagree most emphatically. The whole point of dot notation is that, when combined with properties, it’s not just an alternative syntax for invoking methods. In fact, if that’s how you think about dot syntax, STOP. That’s not what it’s for at all.

What dot syntax and property declarations are for is separating object state from object behavior. Classical OOP only really defines objects as only exposing behavior but the past 30+ years have demonstrated rather aptly that objects consist of both. C# was actually pioneering in this; its concept of properties is rather similar to what the combination of property declarations and dot syntax enable in Objective-C.

To write idiomatic Objective-C 2.0 you should use @property to declare properties, and use dot syntax to access them. Period. Doing otherwise is a bad idea because it will create code that isn’t intention-revealing to other experienced Objective-C 2.0 developers. Teaching students to do otherwise is doing them a disservice, because you’re directly contradicting those responsible for the language and its evolution.

In short, Objective-C 2.0 has properties and dot notation as another way of expressing intent in your code. Use them for that, don’t refuse to use them just because they weren’t in earlier versions of the language, or because they require teaching another concept.

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