A little over a month has passed since Swift came out, and I’ve just pushed a substantial update of my SwiftChecker app to GitHub. (Update: while writing this, I discovered a bug and pushed an updated update!)
While I still have to go back now and then to delete semicolons and to correct “String s” to “let s: String” (!@#$% muscle memory!) I finally can write out dozens of lines of Swift code without going back to the documentation or, worse, spend hours on the Internet checking why the compiler is balking. I suppose that means I’m assimilating the new syntax. It’s been over a decade since I had to learn a new language, so this isn’t too bad. 🙂
Looking at my new code, I’m particularly impressed by the conciseness of the language — the interaction with Cocoa APIs is still quite verbose, of course, but once I got used to type inference, the various map/filter/reduce/join functions, and of course generics, type extensions and operator declarations, I saw new ways of refactoring my code to be both more concise and more understandable.
In my almost 14 years of writing ObjC code I experimented with adding categories to existing classes but for the most part it always felt fragile and, after the initial experimental period, I went back writing subclasses or container classes. Using C macros to simplify stuff was tricky and error-prone. In Swift, by using generic types, it’s possible to write extensions and operators such that they don’t conflict with the existing implementation and this feels much more safe and natural. Although, of course, you still can unintentionally conflict with future additions to the Swift Library, namespaces should mostly take care of that.
Generics and type safety are a great help once I got used to them, which admittedly took some futzing around — the compiler is still very sensitive and the error messages are often cryptic or downright wrong. The type constraints and matching used for more complicated generics, admittedly, can become very complex — especially to someone not current on this new-fangled “type theory”. Still I was able to understand and build some simple generic extensions and functions that could be safely factored out into a few lines and greatly simplify other parts of my code.
Regarding optionals, I quickly got used to them; the old “returning nil” dance is now much less error-prone and at every step it’s clear which type is being handled and when it can be nil or not. The code is more readable in that regard, even if some nested “if let” statements have to remain when handling Cocoa return values. And ARC is practically transparent in Swift.
Speaking of values and ARC, the most troublesome parts are still those APIs — like the Security framework APIs I use in SwiftChecker — which haven’t yet been properly annotated. Certainly this will take many months, but no doubt pending updates to Clang will also take advantage of that, so that we’ll finally get rid of those pesky bridging casts.
One other positive side-effect is that the new whitespace rules, while mostly aligned with my own preferences, are finally making me insert spaces after commas, colons and around infix operators, and take other measures for increased readability.
All in all I’m very optimistic about Swift’s future. Can’t wait for the next Xcode beta to come out; the rumor mill says tomorrow, so let’s hope!