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I hope they actually stick with this. Swift embedded, for example, is a sort of proof of concept more than viable platform, and you end up battling that more than the problem you are trying to solve.

It is a shame because aesthetically Swift is easily the nicest of the modern safe languages, but there have been really odd noises in the community about project leadership that sour things.



guard let self = self else { return }


`guard let` is great what’s there to hate?

The big problem with swift is “expression has ambiguous type” and “expression took too long to type check”. Those don’t trade in code aesthetics but are problems I’ve never had in another language.


There's a shorter form of it:

  guard let self else { return }
which annoyingly the AI's don't know about.


Not much better, to be honest.


Ha! But that's not semantically meaningful Swift code in any normal context, nor is it idiomatic. `self` is equivalent to `this` in C++, and is never normally null.

You use this construct for unwrapping nullable fields, for example something like this:

guard let httpResult else { return }

Note that you don't need to assign the value to itself in modern Swift. This line takes an optional (httpResult?) and returns early if null. If not, you can use it with strong guarantees that it's not nullable, so no need for ? or ! to unwrap it later in the scope.


I've seen that exact pattern used to safely unwrap a weakly captured 'self' within a closure (to avoid retain cycles)


> But that's not semantically meaningful Swift code in any normal context, nor is it idiomatic. `self` is equivalent to `this` in C++, and is never normally null.

It is, when `self` is captured weakly in a closure, and that closure is outliving the instance.


It’s nil in Swift, and what the other comment said ;)


Most use of this is misguided unfortunately :(


This can now be guard let self else { return }


> Swift embedded, for example, is a sort of proof of concept more than viable platform, and you end up battling that more than the problem you are trying to solve.

Yet Apple has managed to create WatchOS. I don’t know what is the portion of Swift, however.


WatchOS is hardly embedded though. An Apple Watch is basically a small iPhone tied to your wrist in terms of architecture. That’s got a whole lot more in common with a full desktop computer than it does with a microcontrollers, where they often have rather weird architectures by desktop standards, and it’s quite rare to have MMUs and things like that. Also, there is no underlying OS, and no heap allocator (unless you provide one). That’s the kind of challenge that an embedded language runtime has to provide.


Which might be one of the reasons why battery lifetime on Apple Watch is so bad.




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