[Liquid_Fire]

Rust doesn't model everything as a shared_ptr, it gives you a choice of tools that fit different use cases - just like C++ does. The difference is if you mess up, it is massively more likely to detect it at compile time.

I agree that starting from scratch can make a huge difference, but if you're starting from scratch anyway why not use the language that will prevent you from making mistakes in your design?

[menaerus]

I did not mean "everything" in the broader context but in the context when it comes to writing "easy" multithreaded programs. Pretty much everything in that case becomes modeled through a shared-ownership or message-passing semantics.

Since those same mechanisms are available in C++, and other languages too, making an argument that some specific XYZ algorithm re-implementation from scratch was more successful only because it was written in Rust, doesn't hold water. It was successful, for the arbitrary definition of success, in its major part because it was a greenfield project.

I believe that suggesting otherwise is plain wrong and misleading.

[Liquid_Fire]

You might be right, but you're stating this without any evidence, so I don't think it's clearly "wrong or misleading". There are many cases of software rewrites failing, so I'm not sure you can take for granted that "greenfield project" implies higher success rate, and even if you did, I don't see how you can judge how much of this was due to it being rewritten from scratch vs that it was in Rust to claim "major part".

[menaerus]

It's common sense what I said. It applies across the industry regardless of the programming languages used. On the contrary, where's the evidence suggesting that the Rust is what made Gecko rewrite succeed? Has there been any rewrite from scratch with some other programming language?

[steveklabnik]

There were two previous attempts at parallelizing CSS layout in Firefox. Both were in C++. Both were abandoned after being unsuccessful. The Servo folks credited Rust's safety guarantees as the reason why they were able to be successful on the third attempt.

https://www.youtube.com/watch?v=Y6SSTRr2mFU

[menaerus]

C++ attempts were from scratch or were based on interventions on the existing codebase?

[steveklabnik]

I mean, the Rust version was also put into the existing codebase, so it's not clear to me what distinction you're making.

But this presentation was made seven years ago, and the attempts it's talking about are even older, and I wasn't involved with them. So I don't know the answer to your question.

[Liquid_Fire]

No, I don't think there's any concrete evidence either way. I'm not trying to argue that it was Rust that made it succeed - I'm sure in reality it was some mixture of both, as well as other factors.

[menaerus]

Having to work and learn through the codebase to make some substantial improvements often requires substantial effort and even rewiring the code architecture itself. That's enough of the evidence for me.