When a basic question is asked, a basic answer is given. I didn’t say that I think that’s the coolest or most interesting answer. It’s just the most obvious, straightforward one. It’s not even about Rust!
(And also, I don’t think things like work stealing queues are relevant to editors, but maybe that’s my own ignorance.)
You cannot have it both ways though. Either these are meaningful examples of Rust's benefits, or they are not worth mentioning.
In a thread about Rust's concurrency advantages, these editors were cited as examples. "Don't block the UI thread" as justification only works if Rust actually provides something novel here. If it is just basic threading that every language has done for decades, it should not have been brought up as evidence in the first place.
Plus if things like work-stealing queues and complex synchronization are not relevant to editors, then editors are a poor example for demonstrating Rust's concurrency story in the first place anyway.
Well, what about small CLI tools, like ripgrep and the like? Does multithreading not matter when we open a large number of files and process them? What about compilers?
Sure. But the more obviously parallel the problem is (visiting N files) the less compelling complex synchronization tools are.
To over explain, if you just need to make N forks of the same logic then it’s very easy to do this correctly in C. The cases where I’m going to carefully maintain shared mutable state with locking are cases where the parallelism is less efficient (Ahmdal’s law).
Java style apps that just haphazardly start threads are what rust makes safer. But that’s a category of program design I find brittle and painful.
The example you gave of a compiler is canonically implemented as multiple process making .o files from .c files, not threads.
> The example you gave of a compiler is canonically implemented as multiple process making .o files from .c files, not threads.
This is a huge limitation of C's compilation model, and basically every other language since then does it differently, so not sure if that's a good example. You do want some "interconnection" between translation units, or at least less fine-grained units.
It reminds me of the joke that "I can do math very fast", probed with a multiplication and immediately answering some total bollocks answer.
- "That's not even close"
- "Yeah, but it was fast"
Sure, it's not a trivial problem, but why wouldn't we want better compilation results/developer ergonomics at the price of more compiler complexity and some minimal performance penalty?
And it's not like the performance doesn't have its own set of negatives, like header-only libraries are a hack directly manifested from this compilation model.
