inessential by Brent Simmons

Random Swift Things

Last night I discussed Swift with some local developers. Some of it stuck in my head today. At random:


It’s two years from now. Your company is hiring, and the best candidate has one drawback: all her experience is with Swift, and she’s barely acquainted with Objective-C. But she knows the frameworks well and has proven experience shipping quality software.

All of your existing code — and there’s a ton of it — is in Objective-C. Maybe there’s a little bit in Swift, maybe not, and maybe you’re open to doing more in Swift, and maybe not.

Do you hire this person?

Swift Is Hard

Objective-C looks hard because of the [ and ] syntax and all those words. It looks kind of mean, actually, like an angry grandpa with bushy eyebrows who makes you spell out “I am laughing out loud” instead of writing LOL.

But Objective-C is easy compared to Swift. Swift looks easier at first blush — every JavaScript developer sees it as familiar, and many think that this might be their way in to writing native apps.

More-familiar syntax will help more people get started, I think. But then you run into concepts that Objective-C doesn’t have to deal with (optionals, generics, and tuples, for instance) and concepts that Objective-C doesn’t have to deal with much (value versus reference semantics, functional design patterns, strict type safety). And you inevitably run into the issue of interoperation with Objective-C — which, obviously, isn’t a problem in Objective-C.

Angle-bracket-T Blindness

I’ll exaggerate a little — okay, a lot — to make a point. A popular form of blog post about Swift seems to be like this:

Here’s how you’d do things the crufty old-fashioned way:

for (id oneObject in someCollection) {
  [self doSomethingWithObject:oneObject];

Well, you can tell by looking just how awful this is. Nasty loopses and untyped types. Let’s do it the modern way…


[snip 200 lines of code]

func x<T> -> x<U> <TT> (in U -> <T>){$1 $2}.map(func y(T)<T><T> -> <U> infix $3 {

Clearly this is hyperbole and ridiculousness and line noise. I’m not being fair. But I think that anybody who reads a bunch of articles about Swift (as I do: I read everything I can find) recognizes what I’m talking about.

(There are many people who write wonderfully about Swift. Two of my favorites are NSHipster and David Owens II. But I still get angle-bracket-T blindness sometimes, even with them.)

Objective-C Hasn’t Finished Evolving

This is a prediction. It’s surely true that Apple has more existing Objective-C code than anyone else in the world. Improving Objective-C — especially if it means making their developers more productive and making their apps better — is in Apple’s best interest.

It’s possible we’ll even see some convergences — changes to Objective-C that make it easier for Objective-C and Swift to work together in the same code base.

I keep thinking it’s easier for Apple to upgrade Objective-C than to redo everything in Swift.

But Swift Is the Future

Swift’s adoption, and the enthusiasm around it, have surpassed my expectations — despite its very-much-still-early position. (If you have a developer account, read Apple’s Swift forum.)

Here’s the thing: if you go searching the web for solutions to some problem involving recent APIs, you’re extremely likely to run into Swift code. It’s happened to me plenty of times already — I’m translating from Swift to Objective-C as I read, which is not something I expected so soon.

Swift is happening.


Yes, I’d hire the person with Swift experience but no Objective-C experience.