Steve Kochan on the Evolution of Objective-C
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Steve Kochan has been using C-family languages for a lot longer than most. He was the author of the second C book published and has more recently been working with Apple platforms. The second edition of his Programming in Objective-C 2.0 text was published at the very end of last year, and he has continued to work with the iPhone since its publication. We talked about his experience with the language and its evolution.
David Chisnall: There are lots of rumours about what will be announced at the keynote this year. Is there anything you're particularly hoping for?
Steve Kochan: I'm not anticipating too many surprises. I assume most of the keynote will center around iPhone OS 3.0 and the upcoming release of Snow Leopard. Perhaps there will be an announcement about the next version of the iPhone, which rumors say may go on sale in July. I'm curious to see where Snow Leopard stands as far as when it will be released. I think there is definitely some sort of tablet/net book on the horizon, but I don't expect any announcements at this show about such products.
DC: What caused you to learn Objective-C originally? Was it very different to other languages you knew at the time, and what features of the language did you like the most?
SK: C has always been my favorite programming language. I wrote Programming in C in 1983, and it was the second book on the language after K&R. I have also been a Mac fan since the first Macintosh and wrote a Mac version of my C text for the Apple Press Library back in the late 1980s. Since Objective-C is based on C and is used as the primary development language for Mac OS X and the iPhone, it's no surprise that I was attracted to this language.
DC: What do you think the biggest hurdle is for a C programmer moving to Objective-C, and what do you miss most when you go back to pure C?
SK: The biggest hurdle is making the transformation from programming with a procedural language to an OOP one. That's why I don't recommend that new programmers learn C first and then Objective-C, which seems to be the route most recommended by everyone else.
DC: Objective-C is a fusion of C and Smalltalk. Before you learned it, had you any prior experience with Smalltalk? If not, has your experience with Objective-C encouraged you to look at Smalltalk?
SK: No, I have no prior exposure to Smalltalk and no desire to look at it.
DC: Have you spent any time working on the iPhone, and if so what do you think the most difficult thing is for people coming from a desktop-Cocoa development environment?
SK: I don't think the transition is really that difficult. The development tools and the frameworks map quite nicely to the iPhone. Anyone with a fair amount of Cocoa programming experience should be able to quickly transition to iPhone application development. Perhaps the idea that memory is dear may be new to Cocoa programmers, as it seems that modern-day programmers assume that they have an unlimited memory store at their disposal for their applications to use.
DC: On a related topic, do you think it's easier for people unfamiliar with Objective-C to learn to program the iPhone or OS X on the desktop?
SK: I don't see much difference here. If it weren't for the iPhone simulator, I would say that developing for the desktop would be easier just due to the convenience. However, the fact that many applications can be developed and debugged completely on the desktop using the simulator largely negates that. If you do have an application that needs to be debugged on the physical device, then that does pose a disadvantage to developing on the desktop. Finally, if you don't want to worry about memory management and want to take advantage of garbage collections, then developing apps on the desktop is easier, as the iPhone OS does not support automatic garbage collection.
DC: The question for every Objective-C 2.0 programmer: what do you think of the dot syntax for property accessors? Love it, hate it, or totally ambivalent to it?
SK: Ahh, I have mixed feelings here. Unlike some, I think Objective-C is an elegant extension to the C language. The dot syntax muddies the water for me. While there are some advantages (not having to write setter/getter methods and the ability to refer to the setter/getter methods with one name as opposed to two), I'm not too thrilled with the visual ambiguity that the dot operator creates with respect to its dual use as a structure member operator. Plus now you can have two ways to send a message: using the dot operator or the [...] notation. A programmer needs to be consistent with their usage in a program (for example, just use the dot operator with properties and not with other instance methods and not write [a release] on one line and then b.release on the next).
DC: Objective-C 2.0 introduced a lot of small changes and a couple of large ones. What are your favourites, and are there any you don't like?
SK: I think fast enumeration is great. As noted, I have mixed feelings about properties and the dot operator in general. Garbage collection is more a feature of the runtime, and while useful for seasoned programmers, I recommend that new Objective-C programmers learn proper memory management techniques first.
DC: I'm told you're currently working on a series of Live Lessons to accompany Programming in Objective-C 2.0. How easy are you finding it to switch media? What are the challenges and what do you like best about creating videos?
SK: Sitting in front of my computer with a headset on and talking to myself has been a strange experience! After recording a few lessons, I finally did get the knack of it. I think the best part is that the viewer can follow along as I type in a program and explain my thought process along the way. That's a different way of learning from reading a book, as it provides the visual coupled with the audio element. It's closer to taking a course with an instructor than simply learning from a text.
DC: What projects are you currently working on?
SK: I've been very active with my forum (www.classroomM.com), and my members have really appreciated my participation. After the LiveLessons project I'm currently completing, there's likely to be one or more books on either iPhone programming or advanced topics in Objective-C (or both). I'm also looking at some other unique ideas to provide training in both Objective-C and the iPhone application development.