rpds VS moodycamel

Another option I can think of - but not completely sure how one would implement in Rust - would be to never mutate the shared state, but rather when updating it - completely swapping it out with a completely new copy of the desired state. There's lots of different ways to go about doing this - each with their own trade offs. But using some form of Persistent Data Structure would probably be a good way to start. If you only have a single writer - then I believe using a Cell and simply updating which version of the structure is being read could work. rpds seems to be a decent start to look at these sorts of structures in Rust.

Thanks for taking the time to provide a detailed response. Need to think on this. I had actually started a regular Clojure parser using LLVM as a hobby, but then my friend said it was better to implement this in a safe-memory and. save-concurrency language like Rust and leverage cranelift for code generation. So, now I am learning rust, lol. (Btw, Rust has a persistent data structures lib too: https://github.com/orium/rpds )

Take a look at https://github.com/orium/rpds or one of the many others.

Other than that... if your stuff is good, that's a much better signal than a professional username. I've seen a lot of decently unprofessional usernames out there that get taken pretty seriously because of the good work behind them. My recent favorite is "moodycamel" who authored a great concurrent queue library in C++.

In c++ the moodycamel ConcurrentQueue is a good choice.

Here's a decent concurrent queue: moodycamel::ConcurrentQueue.

Lock free programming is hard, and probably harder than you think. I would not even try something like that myself. I would look for existing solutions, something like https://github.com/cameron314/concurrentqueue for example.

I needed a concurrent queue that would block when attempting to pop an empty queue, which allows the consuming thread to suspend while it's waiting for work. I found that using mutexes allowed me to develop a simple template adapter had several advantages with few drawbacks when compared to non-blocking queues: it can use a variety of containers, the code can be reviewed and verified as to its correctness (very hard to do with fancy concurrent programming that avoids mutexes), and it is only slightly slower than fancier solutions (when I benchmarked it originally, it was 4x slower than Moody Camel's concurrent queue, which to me is fine performance).

Not literatue but an example. This is a lock-free (not wait-free!) multi-producer multi-consumer queue, not a FIFO, but access patterns should be similar - if not the same: https://github.com/cameron314/concurrentqueue

If I do implement it, the most likely route I'd take is make a compiler in Clojure/clojurescript that uses Instaparse (I have a more-or-less-clojure grammar written that I was tinkering with) and generate C++ code that uses Immer for its data structures and Zug for transducers and what my not-quite-clojure would support would be heavily dependent on what the C++ code and libraries I use can do. I'd use Taskflow to implement a core.async style system (not sure how to implement channels, maybe this but I'm unsure if its a good fit, but I also haven't looked). I would ultimately want to be able to interact with C++ code, so having some way to call C++ classes (even templated ones) would be a must. I'm unsure if I would just copy (and extend as needed) Clojure's host interop functionality or not. I had toyed with the idea that you can define the native types (including templates) as part of the type annotations and then the user-level code basically just looks like a normal function. But I didn't take it very far yet, haven't had the time. The reason I'd take this approach is that I'm writing a good bit of C++ again and I'd love to do that in this not-quite-clojure language, if I did make it. A bunch of languages, like Haxe and Nim compile to C or C++, so I think its a perfectly reasonable approach, and if interop works well enough, then just like Clojure was able to leverage the Java ecosystem, not-quite-clojure could be bootstrapped by leveraging the C++ ecosystem. But its mostly just a vague dream right now.

I would recommend https://github.com/cameron314/concurrentqueue as it's very battle tested and fast.

This was explicitly considered for spdlog (using the moodycamel::ConcurrentQueue) but rejected for the above reason. I'm not involved in the development of spdlog but personally I agree, for me it's important that log output is not all mixed up.