Clean Code at NSConference
February 01, 2010

Dave Dribin was preaching to at least one of the converted (me), in his “Clean Code” session at NSConference today - but then I have to wrestle with very large bodies of C++ code every day, much of which was written by other people not following any of his guidelines!

Most of the stuff he said was uncontroversial, but it was amusing to see a few people in the audience bristling at one or two of the suggestions that Dave made - you could hear the cogs turning in their brains as they thought “but I do that all the time, and I’m smart, so he must be wrong”.

I can’t really offer an opinion on KVO vs Delegates, not having done enough Cocoa work, although I think it’s all a storm in a teacup anyway as he was simply offering a personal order of precedence. Having had to debug very complex systems I can see where he was coming from though. KVO sounds like a lovely way to decouple systems, but it can get scary when just “setting values” can cause a rich ripple of side effects that extends way beyond the object you thought you were playing with.

I do think Dave’s right about singletons - at the end of the day they are globals, but somehow we’ve ended up with design pattern books telling us about them, and people like Scott Meyers telling us how to implement them efficiently, and it’s blinded us to the fact.

The point that some people seemed to be missing was not that they aren’t useful (they can be), or even that they aren’t the right or pragmatic solution to some problems (they can be). It’s just that they often aren’t the best solution, and yet it is dangerously easy to fall into the trap of making them when you don’t need to - I know, I do it all the time, with the best of intentions. And Dave was right - using a singleton you can easily end up with annoying hidden dependencies and inflexibilities which you can avoid if you instead use a pattern where you pass in the services/resources that you need. And it does make life particularly hard if you want to do test driven development and unit test the hell out of everything.

I never felt that Dave’s tone was in any way preachy, but maybe some people wondered why he was telling them stuff that “we already know”. Perhaps it’s also just a very healthy skepticism in the audience towards received wisdom, which is fair enough - I’m all for that. But just because it’s received wisdom, it doesn’t always make it wrong, any more than it makes it right!

In any case I’m not at all convinced that everyone in the room does know all that stuff. There were plenty of indy developers in the room, who are working on there own a fair amount of the time, many of whom are 25 or younger. I’ve also met plenty of developers in my life who’ve been doing coding professionally for years and still haven’t got a clue!

When I was 21 and just out of college I was lucky enough to get a great job working in an university research department, writing educational software in Hypercard (with plenty of lovely XCMDs that I wrote too). It was a brilliant job and a fantastic environment in many ways, with loads of freedom for someone just out of college. At the tender age of 21 though, I was the only full-time developer and with the benefit of hindsight I realise that I missed out on a great deal of stuff that was going on at the time in the wider software engineering world, because there was nobody at work to point me in the right direction. I was totally focussed on what I was trying to make, and not on the process of how it got made. Things are a lot better now than they were in 1992 of course, and it’s a lot easier to stay in touch with the current trends in computer science through the sort of social networking that we now have. But you still occasionally need people to tell you stuff, even stuff that you’re supposed to already know.

There’s definitely no harm in being reminded of some of the basics from time to time, and having some of your assumptions challenged - whether you’ve been doing programming for 1 year or 5 years or 30.

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