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by airstrike22 hours ago |
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upvoteby AceJohnny220 hours ago|
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Rust doesn't have an ABI [1]. Swift needed one to be a useable application language:

https://faultlore.com/blah/swift-abi/ (written by a core Rust developer)

[1] apart from the basic/universal C one, which prevents exposing any useful Rust semantics over the interface

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upvoteby afavour20 hours ago|
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One of the genius things about Swift is its interop with Objective C. Made the switch over considerably easier for developers. I’m not sure what that looks like in a Rust world.

Rust is also just a more complex language. I’m not convinced the benefits would have been worth it.

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upvoteby inkyoto14 hours ago|
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Not just interoperability with Objective C but with C (full) and C++ (increasingly better but not full) as well.

Swift is also interoperable with different versions of itself courtesy of the Swift stable ABI (Application Binary Interface)[0], which they invested a significant amount of time into at the expense of adding other new features to the language, which have come along later.

Rust offers a different approach: recompile everything and static linking.

[0] https://faultlore.com/blah/swift-abi/

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upvoteby pjmlp11 hours ago|
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C compatibility comes via Objective-C, because contrary to C++, Objective-C extends C, instead of being based on a C subset.

You missed Java as well.

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upvoteby jadengeller21 hours ago|
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Modern Swift borrows a lot from Rust! And it also has its own benefits, both ergonomic and also supporting eg generic in dynamic libraries
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upvoteby airstrike21 hours ago|
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These days I mainly write Rust but I did write a semi complex iOS app and enjoyed Swift. I just didn't love how slow the type checker was and how it got lost. I recall having to break things into smaller bits to help the compiler, and there were some oddities about the language.

The gap between the two languages is quite small, it just makes me wish Apple was also all-in on Rust

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upvoteby geodel4 hours ago|
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Apple is not going bet all on language whose roadmap they do not control 100%.
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upvoteby MBCook19 hours ago|
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In the last year they’ve added improvements to the type checker to speed it up, those would have been released now.

They have further and much more significant changes that I think might have recently landed in the development version. That should make an even bigger difference. But it’s not in a released version yet.

And yes, none of us like that one part of Swift. Especially the DRASTIC difference compared to objective-C which really only checked syntax and little else.

It’s still probably my favorite language right now though I don’t get to write in it much.

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upvoteby DenisChetwynd21 hours ago|
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maybe so on the surface, but it remains quite massive underneath; these languages are fundamentally different and target entirely different use cases
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upvoteby airstrike19 hours ago|
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I'm not sure Rust has one specific use case as its main goal, despite being immediately suitable for systems programming.

I use it for making user-facing desktop applications, to name one example.

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upvoteby inkyoto14 hours ago|
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I see Swift as a more approachable version of Rust.

If somebody is mulling over Rust but finds it too difficult to grasp, they could start off with Swift first and then move over to Rust.

One of the main advantages of Rust is a more developed and thriving ecosystem.

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upvoteby stasomatic10 minutes ago|
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It has an unfortunate name though, maybe a short shelf life. Rust++ doesn’t seem inviting either.
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upvoteby ecshafer21 hours ago|
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Swift and Rust were developed at similar times. I think of them more as having similar influences than borrowing from each other.
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upvoteby pohl18 hours ago|
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There’s no reason to invent your own head canon, the influence was openly acknowledged when Swift was new and it continues now that the language is developed out in the open (see Swift Ownership Manifesto)
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upvoteby zarzavat16 hours ago|
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Obviously Rust was first but over time both languages have been taking inspiration from each other. For example let-else was motivated directly because of its success in Swift: https://rust-lang.github.io/rfcs/3137-let-else.html#prior-ar...
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upvoteby pjmlp12 hours ago|
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Additionally both have influences from CLU, C++, Object Pascal, Modula-2, Mesa/Cedar, Standard ML, Cyclone.

Many features that get discussed as being Swift/Rust, trace back to one of those languages.

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upvoteby est3121 hours ago|
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Similar times and the Rust originator went on to work on Swift after it.
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upvoteby DenisChetwynd21 hours ago|
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Graydon Hoare's impact on the language is marginal than that of Chris Lattner, the originator (also, Hoare joined the team much later)
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upvoteby vardump21 hours ago|
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Does it borrow borrow checker?
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upvoteby tialaramex20 hours ago|
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I believe Swift tends to use reference counting and copy-on-write strategies. This, like GC, is less for the programmer to think about and doesn't require the semantic checks, but sometimes the performance cost is unacceptable compared to what you'd write in Rust.
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upvoteby airspeedswift19 hours ago|
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You can choose to use either refcounting or unique ownership for your types. For most use cases, refcounted (+ copy-on-write) is the best choice and is the default, but the truetype interpreter made extensive use of non-refcounted types to achieve this performance.
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upvoteby pjmlp11 hours ago|
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You can pick and chose, and memory ownership is getting better in latest versions.

Being more ergonomic is relevant enough for increasing language adoption, that possible improvements are now on Rust roadmap.

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upvoteby MBCook19 hours ago|
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They have either recently added or talked about a borrow style system in the language as a way to avoid more copies and speed things up/lower memory usage/help with asynchronous programming.
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upvoteby 21 hours ago|
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deleted
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upvoteby anextio20 hours ago|
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Yes, it has a borrow checker.
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upvoteby pjmlp11 hours ago|
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Swift takes the right approach in language ergonomics, many of its use cases would be much harder with explicit .clone() all over the place, lack of back references, no standard ABI for binary libraries, interop with Objective-C and C++, no standard concurrency runtime, or error handling types.

Rust 2026 roadmap has language ergonomics on it for a reason.

That said, outside Apple ecosystem you probably better with Rust, or if one has no GC issues, OCaml, Haskell, F#, Scala, C#.

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upvoteby jounker9 hours ago|
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Apple has a runtime system that looks a lot like smalltalk. Everything at that layer is dynamic. They needed a language that could seamlessly interact with that system.
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