I've developed and maintain 3 or so swift apps in the last 4 years.
I also assist a colleague who ports and maintains them in Kotlin.
At first I liked Swift. As a dynamic OO languages guy, I didn't like C++, and felt that Swift was a fresh approach to the non dynamic OO language. Over time, my enthusiasm has waned.
For a while, I drank the value /struct programming koolaid. Too much. It turns out, that references are really really handy when your modeling real world things. Time and time again I've pushed myself to go the protocol route with structs, only to pull it out and just use simple single inheritance with real class based objects.
The real trap I keep falling into is this. The Swift memory management story for objects is a fricking joke. First you have to constantly stress about ownership relationships, so that you don't get burned by cycles. And then you get to discover the various behind the scenes implicit refcointing rules around closures or passing methods directly in lieu of closures. And having to put [weak self] everywhere. So you react by using structs more. Because you believe it will be more efficient, etc. But structs come with their own problems. You put ids in your structs, because you need to assert identity of a given thing. Abstraction is more difficult. You get to dance with generics more.
I've played with SwiftUI, I get the basic dream. It demos well. I could use it for simple CRUD style apps (which is what all the tutorials seem to be for). I'm just not sure how well it will scale to more complicated user interactions.
As much as I don't like Android development and loathe Java, I'm forced to often just wish I could use Kotlin in iOS. It has its warts. And often there are too many ways to do one thing so that they can streamline a tiny amount of boilerplate away at the expense of consistency. But I fight it less.
There some truth to that I guess, but I'd also add that a lot of these modern multiparadigm languages feel like they're converging feature-wise (with a few outliers). I feel like Swift still has a unique enough feel to it and I enjoy working with it a lot. I think Chris Lattner has also expressed some concern about the focus on features over everything else.
That said, automatic differentiation could be a game-changer and should absolutely be included in the core language.
Seems to me like there's at least an argument that it should be possible grow diff programming into a general purpose meta programming system rather than use general purpose meta programming as implementation mechanism for differentiable programming ...
None of this is new per se; weird Apple specific edges like @UIApplicationMain and @NSManaged have always polluted the language. But, it's hard to buy in on "Swift world domination" when server-side Swift is stillborn, Rust is more appealing as a better bare metal language, Catalyst and SwiftUI are weaker than AppKit and UIKit, the last time Swift got a useful language feature was guard let in Swift 2.
On the point of "swift world domination", I still think this is largely a PR problem. I think Swift's identity as "compiled python" could make it a very good fit for many use cases where scripting languages are currently being used, due to it's clean, high level syntax and powerful type system. It still suffers a chicken-and-egg problem with respect to broader tooling and library support since it's viewed overwhelmingly as a language for making iOS apps.
Swift as a "compiled python" loses to Go, and that not even Go's design goal (though it is a fairly common use of it).
Does it have to be "ideal" to be worthwhile? I think it fits a similar use-case to something like C# but it's a lot nicer to work with. I don't understand why Swift shouldn't be perfectly usable for data science, or writing server-less functions for example: it would be a perfectly suitable stand-in for Python or Go in these cases, but with a much nicer type system in my opinion thanks to the first-class optional handling.
> Swift as a "compiled python" loses to Go, and that not even Go's design goal (though it is a fairly common use of it).
I totally disagree. Go is a jail. It's optimized for big teams with a lot of turnover, where you want to prevent complexity in the code-base by choosing a language with very limited facilities for abstraction.
Swift on the other hand has a really flexible syntax, which allows you to hide a lot of complexity behind simple interfaces. In that way, it can be a lot more like Python, where the code you're writing is very much at the domain level, and you don't have to think about the implementation details very often. There are many things you can express in swift which are no expressible in go.
It runs circles around storyboards when it comes to collaboration and traceability. Disregarding bugginess, the previews are a lot better than what was possible with IBDesignables.
The integration with UIKit is actually quite well made, and for most part not needed.
> there's no new hardware forcing its adoption.
While there is no explicit new hardware, there are several popular features that are only doable using SwiftUI: home screen widgets and complications. It will also become the language in which to write universal iOS/macOS programs.
> when server-side Swift is stillborn, Rust is more appealing as a better bare metal language
I agree with this, at least from Apple's part most effort is clearly done on "application level" and usefulness of Swift outside there seems more exploratory at the moment. Personally I'd like them to start adding higher, rather than lower level functionality, and steer towards scripting.
This here makes sense. I can see Swift becoming more focused on the application-level side at the moment and in the future becoming a way of writing cross-platform GUI apps in Swift, more likely if it is with Qt5 with direct C++ interop with a SwiftUI-like DSL.
As a Rust user, the server-side use-case for Rust is far more developed unlike Swift and would much rather see Rust pushing for low-level development as well.
However, I've seen many attempts for a cross-platform GUI library for Rust for a long time and it has been proven to be difficult in terms of adoption, implementation and maintenance. It would take an enormous amount of effort to cover all three of these difficulties from scratch and using bindgen bindings to wrap and maintain it and I'm afraid for them it would be more trouble than it is worth. But who knows?
I just don't see a mature cross-platform GUI library coming from the Rust ecosystem anytime soon.
It doesn't interact well with other language features (e.x. if let wasn't supported for a long time), it isn't really extensible (transforms are specified by the language), and yet it adds a bunch of complexity in both the language, implementation and reading code.
It seems clear, at least to me, that this is something that happens if you try to make a feature 'generic' without a lot of time and design consideration, due to Apple's internal politics on SwiftUI. I like SwiftUI, and some features that support it are great (like custom attributes), but I firmly think that they should have taked the time to produce a better design.
[0]: https://github.com/apple/swift-evolution/blob/main/proposals...
https://www.quora.com/Which-features-overcomplicate-Swift-Wh...
That was 2015, when Swift was far simpler than today.
Heck, they added almost all of Smalltalk syntax recently to address one special case of a special case.
https://blog.metaobject.com/2020/06/the-curious-case-of-swif...
And the method syntax that this is a special case of a special case of is many pages of spec.
And of course there's initialization, which was 14 pages of the Swift spec at the time, with crazy overlaps and gotchas. Unsurprisingly and predictably (as in: I predicted it), it wasn't enough, or rather far too specific, so for SwiftUI they had to create an entirely new way of creating/initializing: function builders.
https://blog.metaobject.com/2020/04/swift-initialization-swi...
Multiple trailing closures fit a common use case and seem like a natural extension of the language.
Absolutely.
But Swift wasn't parsimonious at first. Not even close. It unwisely rejected the parsimonious case and chose tremendous complexity.
Keywords? Or parens? Both! And we'll throw in a bunch of other stuff as well. And the weird case of having two keywords, one with a colon and one without, because we decided to make the keywords the names of the parameters. Sometimes.
And then afterwards they noticed that the parsimonious choice that they had initially rejected in favor of their much more complex choice was needed in addition to all that initial complexity.
> Keywords? Or parens? Both!
Why should they be mutually exclusive?
Swift's named parameters are great! For instance they allow for default parameters, which is something I really miss in Rust for instance where I have to use the builder pattern everywhere.
> And the weird case of having two keywords, one with a colon and one without, because we decided to make the keywords the names of the parameters. Sometimes.
Swift's rules for parameter naming are very simple, consistent, and easy to understand. Given the signature:
func foo(first second: Type)
func foo(x: Int)
func foo(x x: Int)
Yes, regretfully.
>> Keywords? Or parens? Both!
> Why should they be mutually exclusive?
Because of parsimony. The comment I was replying to made the claim that the original Swift design war parsimonious. It wasn't.
> Swift's named parameters are great!
Named parameters are great. Swift's implementation of named parameters is deficient, and not parsimonious. Yes, even that design is better than not having named parameters, but once you have named parameters, you don't need the parens.
Can you share an example of what this would look like in practice? I'm having trouble thinking of how this syntax would work.
var a, b, c;
...
a = b.fooBar(1, 2);
c = a.fooBarBaz(1, 2, a);
|a b c|
...
a := b foo:1 bar:2.
c := a foo:1 bar:2 baz:a.
...
The Smalltalk syntax is hard for me to parse, but it's probably just a familiarity thing. I remember when I first learned Swift I wasn't fond of not ending lines with semicolons. Now I dislike having to type them in languages where they're required.
1 to: 20 do:[ :i | Transcript show:i. ]
1 to: 20 do:{ stdout println:$0. }
While binary and unary messages chain w/o problems, it's not possible to disentangle two keyword messages:
receiver msg1:arg1 msg2:arg1
receiver msg1:arg1 msg1:arg2
But not always, it turns out. If you actually chain messages to the same receiver, you can use the semicolon to chain those messages:
myRect x:20;
y:10;
width:100;
height:100.
In Objective-S[1], you can use the pipe ("|") to chain message-sends that go to the result of the previous message, rather than its receiver. For example:
self dictionariesForQuery: "select {column} from {table}" | collect | at:column.
> delineating the argument set for a single function is the main job parens fulfill.
Right. Which is one of the many reasons why the case of Swift is so mind-boggling: there some of the parameters go inside the parens, some outside. I think you can make a good case for either all in or all out (better for all-out, IMHO, but whatever). But partly in and partly out?
Swift's keyword syntax isn't complex at all.
> Keywords? Or parens? Both!
I know you like Smalltalk, but keywords and parens are used together in a lot of languages (e.g. Python) so it's a tested idea.
> And the weird case of having two keywords, one with a colon and one without, because we decided to make the keywords the names of the parameters. Sometimes.
You don't have two keywords, you have an optional variable name. It's intuitive at the first time you see it - you're phrasing makes it seem much more complex than it really is.
I think you're trying to imply that Swift isn't an elegant language with it's syntax fitting in a postcard, but that doesn't mean it's 'tremendous complexity'. This whole comment is a bit too harsh to Swift, calling the legitimate differences between Swift and Smalltalk as 'complexity'.
> Swift's keyword syntax isn't complex at all.
Yes it is, particularly compared to the parsimonious options. Either parens or Smalltalk-style keywords can do the job, so you absolutely, positively do not need both.
Particularly, if you are going to have keywords, you just don't need parens. So it's already more complex than it needs to be (not parsimonious). Just explaining the various omitted or extra keywords takes 4 pages in the Swift book, the entire Smalltalk syntax fits on a Postcard.
What is complex or not obviously depends on what your baseline is. If it's C++, Swift might seem simple (though many disagree).
> (e.g. Python) so it's a tested idea.
The question was not whether it was tested, but whether it was a parsimonious design, which it is not. It was also not a good design, because it led to a number of follow-on problems that they had to incrementally fix while adding even more complexity.
Python is not a good comparison because they didn't really have a choice: they already had the paren syntax, which they could hardly deprecate.
However, choosing that design without a backwards compatibility restriction is unconscionable, IMHO, particularly if you already have a different keyword design all over your code-base. That's cutting off your nose to spite your face.
Anyway, even the baseline keywords-in-parens is complex and more complex than it needs to be (because it isn't parsimonious), but then you get follow-on problems: blocks inside parens are really ugly, so you add trailing closure syntax. Yet another special case, which is very different from arguments inside the parens. But then you discover that sometimes you need more than one trailing closure, and then you need yet another special case, the open-keyword-trailing-block syntax, which is different yet again.
Of course, instead of having 3-4 different syntactic mechanisms, you could have chosen just the one and not needed any of the others.
> You don't have two keywords, you have an optional variable name. It's intuitive at the first time you see it
No, it's absolutely positively not the least bit intuitive. And it makes no sense, because internal variable names have no business leaking to the interface. If you want to rename the names of your variables inside your method, it changes the signature! Not even C does this.
> that doesn't mean it's 'tremendous complexity'
Although the argument could be made, I wouldn't, not by itself, no. However, this is just one example of countless others, see for example Rob Rix, whom I quoted before:
Swift is a crescendo of special cases stopping just short of the general; the result is complexity in the semantics, complexity in the behaviour (i.e. bugs), and complexity in use (i.e. workarounds).
I also talk more about it here:
https://blog.metaobject.com/2015/05/i-am-jealous-of-swift.ht...
> is a bit too harsh to Swift,
Nope. The comment I replied to made the indefensible claim that Swift was parsimonious. Which it's not. Not even close.
I do agree in general that Swift can benefit from a reduction of special cases, but my personal feeling is that Swift is getting more consistent every version (at least in the features that already existed). YMMV, of course.
How so? That is literally what they did. The trailing closure syntax is Smalltalk keyword syntax, and so Smalltalk keyword syntax is used for that one special case. Which exists in addition to the non-keyword trailing closure syntax and the non-trailing (regular argument) closure syntax.
> but it's not fair to say Swift 'added Smalltalk syntax to address a special case'.
Can you explain how it is "unfair" when that is exactly what happened? Smalltalk syntax is really compact, there just isn't that much there.
Exactly. Which is why I wrote "they adopted the syntax", not "they adopted the ideas". It would have been really wonderful had they adopted the ideas, and it would also have made their marketing slogan "Objective-C without the C" actually truthful.
> the ideas are different
Yes, and that's the problem.
> Trailing closure syntax is basically 'you can remove the parens if there are trailing closures'
Not really, no. The parens are still all there, you just move one (original trailing closure syntax) or more (new keyword trailing closure syntax) of the parameters outside the parens.
Which is horribly inconsistent just by itself. I mean, the point of the parens is that they delimit the arguments. If you have parens, then the arguments go inside the parens. Except for this one...did I say one, I meant these two special cases where the arguments do not go inside the parens.
If you are going to have some of the arguments be outside the parens, why not just go all in and have all of them "outside" by just getting rid of the parens and be (a) consistent and (b) dramatically simpler and (c) readable?
> which was inspired by Objective-C, which was inspired by Smalltalk.
> I don't think Smalltalk influenced that syntax any more ...
Which is it?
Anyway, the point of the article wasn't that they consciously decided to adopt Smalltalk syntax. The point is that they bungled this so badly that they ended up adopting the very Smalltalk syntax that they initially rejected, and the reason they ended up adopting it was that they couldn't make things work reasonably any other way. Except that had they done this from the beginning, they would have not run into any of these problems.
Cathedral and the Bazar..
You are basically complaining about how messy the bazar model is, and yet the bazar gave us Linux and in the end it won the race against all the others working over the Cathedral model and with millions of dollars invested in them.
Its fine to work at the bazar model, and it seems messy at first, but as long theres a 'cathedralization' phase from time to time it will work as a living entity, with constant organic evolution.
I’ve got a feeling that swift is becoming a very polluted mashup of features that come from parties with conflicting interests. AFAIK, internally at Apple, teams pull in different directions (e.g. to get SwiftUI), at the same time there’s this half-baked differentiable programming / swift4tf manifesto, then there’s the backend swift initiative with vapour.
This reminds of a hotch-potch that Scala’s framework and feature landscape is. The overhead of getting into it is quite substantial and for some, definitely not worth the investment if not just downright scary.