Wwdc 2015 video software#
Wwdc 2015 video code#

Well, Crusty has a whole rant about how this plays out. 'First, you got your automatic sharing.' Now you all know what this looks like.Ī hands B some piece of perfectly sober looking data, and B thinks, 'Great, conversation over.' But now we've got a situation where A and B each have their own very reasonable view of the world that just happens to be wrong.īecause this is the reality: eventually A gets tired of serious data and decides he likes ponies instead, and who doesn't love a good pony? This is totally fine until B digs up this data later, much later, that she got from A and there's been a surprise mutation. And he started in on his list of complaints. I have got three major beefs with classes,' said Crusty. 'First of all, I do customization whatchamacallit all the time with structs, and second, yes, classes are powerful but let's talk about the costs. 'Obviously, now you have to bow down before the power of the class.' 'Hold on just a darn tootin' minute,' he replied. That allows the difficult logic to be reused while enabling open-ended flexibility and specific variations. So, for example, a superclass can define a substantial method with complex logic, and subclasses get all of the work done by the superclass for free.īut the real magic happens when the superclass author breaks out a tiny part of that operation into a separate customization point that the subclass can override, and this customization is overlaid on the inherited implementation.

Wwdc 2015 video code#

Obviously, it has to come from something that you can only do with classes, like inheritance.Īnd this got me thinking specifically about how these structures enable both code sharing and fine-grained customization. So I took a step back and tried to figure out what core capability enables everything we've accomplished with object-oriented programming. Because it's true, in Swift, any type you can name is a first class citizen and it's able to take advantage of all these capabilities. Īnd if that wasn't bad enough, a moment later he finished the sentence.

Wwdc 2015 video software#

These properties, they directly address the problems we're trying to solve in software development.Īt that point, I had gotten myself pretty inspired, but Crusty just snorted and. So if a class author leaves something out that I need, well, I can come along and add it later.Īnd, furthermore, together, these things, these things let us manage complexity and that's really the main challenge in programming. Last, classes are open for extensibility. We can even make properties that do computation. So we can write method calls and properties and chain them together. They give us a namespace, which helps prevent collisions as our software grows. Then we use classes to represent relatable ideas, like window or communication channel. So first you can group related data and operations.Īnd then we can build walls to separate the inside of our code from the outside, and that's what lets us maintain invariants. 'Come on,' I said to him as I walked over to his old-school chalkboard. And, furthermore, lots of the amazing things that we've all built together, you and I and the engineers on whose shoulders we stand, were built with objects. I mean, object-oriented programming has been around since the 1970s, so it's not exactly some new-fangled programming fad.

Like last month we were talking about app development, and said flat out, 'I don't do object-oriented.' I could hardly believe my ears. Now I've learned to expect Crusty to be a little bit cynical and grumpy, but even so it sometimes takes me by surprise. No, he favors an 80 x 24 terminal window and plain text, thank you very much.Īnd he takes a dim view of the latest programming fads. Crusty is that old-school programmer who doesn't trust debuggers, doesn't use IDEs. Now you've probably all worked with some version of this guy. I'm here to talk to you about themes at the heart of Swift's design, and introduce you to a way of programming that has the potential to change everything.īut first, let me introduce you to a friend of mine. What we're going to do together here won't necessarily be easy, but I promise you if you stick with me, that it'll be worth your time. The next 40 minutes are about putting aside your usual way of thinking about programming. It is great to see all of you in this room. My name is Dave Abrahams, and I'm the technical lead for the Swift standard library, and it is truly my privilege to be with you here today.