Comment by meisel
6 days ago
Why did Ladybird even attempt this with Swift, but (I presume) not with Rust? If they're going to go to the trouble of adding another language, does Rust not have a better history of C++ interop? Not to mention, Swift's GC doesn't seem great for the browser's performance.
https://x.com/awesomekling/status/1822236888188498031 https://x.com/awesomekling/status/1822239138038382684 "In the end it came down to Swift vs Rust, and Swift is strictly better in OO support and C++ interop."
Did they consider using Nim? It has great C++ interop, OO and same ARC memory management as in Swift.
> In the end it came down to Swift vs Rust, and Swift is strictly better in OO support and C++ interop
Why not D?
Why not rust? It's popilar, in wide adoption, with wide support, without the baggage of C++. What'e the downside?
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> Swift is strictly better in OO support and C++ interop
Fascinating.
They've shown the idea it is better on C++ interop is wrong.
I don't know enough to say Rust has same OO support as Swift, but I'm pretty sure it does. (my guess as a former Swift dev: "protocol oriented programming" was a buzzy thing that would have sounded novel, but amounted to "use traits" in rust parlance)
EDIT: Happy to hear a reply re: why downvotes, -3 is a little wild, given current replies don't raise any issues.
Rust has straightforward support for every part of OOP other than implementation inheritance, and even implementation inheritance can be rephrased elegantly as the generic typestate pattern. (The two are effectively one and the same; if anything, generic typestate is likely more general.)
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They demonstrated that swift's c++ interop isn't good enough, but does it follow that rust's is better? Genuinely asking, as I don't have experience with that. I would imagine that if they rejected it for that reason originally they forsaw even more severe issues.
> Why did Ladybird even attempt this with Swift, but (I presume) not with Rust? I
Probably the same reason why Rust is problematic in game development. The borrow checker and idiomatic Rust do not go well together with things that demand cyclic dependencies/references. Obviously there are ways around it but they're not very ergonomic/productive.
Swift actually has excellent C++ interop [1] (compared to other languages, but, I guess, not good enough for Ladybird).
[1] https://www.swift.org/documentation/cxx-interop/
I actually looked into that recently (calling C++ from Swift), and I was surprised by the amount of limitations.
Said differently: the C++ interop did not support calling the C++ library I wanted to use, so I wrote a C wrapper.
Binding to C++ is an extremely difficult and complex problem for any language that is similarly rich and has lots of (seemingly) equivalent features. The number of subtle incompatibilities and edge cases becomes nearly endless. It's not surprising that some C++ code can't be bound properly.
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I did this a long time ago as Swift calling Objective-C++ which can call C++ libs, in that case OpenCV. So it wasn't awful but did require making an ObjC++ wrapper, unless I did something wrong which is also possible.
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Andreas Kling said Rust lacks OO, which he says is useful for GUI coding.
He even made an attempt at creating his own language, Jakt, under SerenityOS, but perhaps felt that C++ (earlier with, now without Swift) were the pragmatic choice for Ladybird.
But wasn’t Rust designed specifically for being a language for developing a rendering engine / web browser?
Rust initially started as a hobby project of a person who happened to be a Mozilla employee and later got sponsored by the foundation however it was not a language that was specifically designed with browsers in mind.
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> Rust designed specifically for being a language for developing a rendering engine
Rust was born at Mozilla, sort of. It was created by a Mozilla employee. The first "real" project to put it into action was Servo of which parts were adopted into Firefox. While Rust may not have been developed "specifically" to create a browser, it is a fair comment.
That said, Ladybird was started as part of the SerenityOS project. That entire project was built using C++. If the original goal of Serenity was to build an opeerating system, C++ would have felt like a reasonable choice at the time.
By the time Ladybird was looking for "better" languages than C++, Ladybird was already a large project and was making very heavy use of traditional OOP. Rust was evaluated but rejected because it did not support OOP well. Or, at least, it did not support integration into a large, C++ based, OOP project.
Perhaps, if Ladybird had first selected a languge to write a browser from scratch, they would have gone with Rust. We will never know,
We do know that Mozilla, despite being the de facto stewards of Rust at the time, and having a prototype web browser written in Rust (Servo), decided to drop both Rust and Servo. So, perhaps using Rust for browsers is not as open and shut as you imply.
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As someone who was on that team for a long time, we took that into consideration, but it was never specifically for that. There was some stuff the Servo team would have liked us to have implemented that we didn’t.
No. It was developed as a general purpose language.
I think you are conflating the development of Servo with the design and development of Rust.
Might not be the best choice for browser chrome, where an OOP paradigm for GUIs might make sense.
It will be interesting to see any further justification; I believe Rust was rejected previously because of the DOM hierarchy/OOP but not sure IIRC.
20240810 https://news.ycombinator.com/item?id=41208836 Ladybird browser to start using Swift language this fall
Here's Andreas Kling's general thoughts on Rust:
- Excellent for short-lived programs that transform input A to output B
- Clunky for long-lived programs that maintain large complex object graphs
- Really impressive ecosystem
- Toxic community
https://x.com/awesomekling/status/1822241531501162806
I think that's fair. Funny to have a language that makes it prohibitively difficult to use most of the core computer science constructs (lists, graphs etc.).
I so wholeheartedly agree. You are making a new web browser - akin to a new OS - and you want it open source for everybody but you choose swift not rust?
This experiment has shown that both are actually bad choices.
Oh? They tried rust?
Lots of people seem really committed to OOP. Rust is definitely a bad fit if you can't imagine writing code without classes and objects. I don't think this makes rust is a bad language for the problem. Its just, perhaps, makes rust a bad language for some programmers.
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The ladybird developers tried Rust and Swift both and voted to adopt Swift.
Also I believe one of the core LadyBird devs was an ex Apple employee on WebKit which has been using Swift as well.
The Ladybird founder was one of the original KHTML devs and worked on Safari at Apple.
I’m not even sure he was at Apple when Swift came out. WebKit integration is very recent.
Swift doesn't use a garbage collector.
ARC is GC, Swift definitely uses GC.
It isn't a _tracing_ GC
I remember watching the project lead say something like “the developers just don’t enjoy rust”
Swift != GC