Thanks. If I'm understanding correctly: with Isolated (which is still being built), any given object is reachable from only one thread. It can be used for message-passing but not shared memory.
It looks like they've talked about shared memory as important for efficiency, eg https://nim-lang.org/araq/concurrency.html (from back in 2013 apparently, and I don't know if it's a "canonical" project view or not) says:
> For real CPU efficiency on commodity hardware shared memory is unavoidable. Message passing doesn't cut it and ultimately doesn't address the same problems. (http://www.yosefk.com/blog/parallelism-and-concurrency-need-...) Also shared mutable memory is unavoidable in a systems programming context.
(I agree with that statement, fwiw.)
It sounds like they haven't built support for shared memory yet; correct? and as this Isolated construct is also in progress, I think there's basically no threading support in Nim yet?
Are they still intending to build shared memory as well as Isolated? Is it intended to be memory-safe (as in the Rust terminology) or not?
> It sounds like they haven't built support for shared memory yet; correct? and as this Isolated construct is also in progress, I think there's basically no threading support in Nim yet?
You can do shared memory already. There's concurrent hashes and lists, and full threading support. But currently it's on the programmer to not mess up the GC on shared data (eg ensure data graphs are isolated, but it's not too tricky). I use the ESP32's shared queue data structure in the esp-idf to move Nim's native JSON types between FreeRTOS tasks. It's non-copying and more efficient than normal message passing. I also use some shared globals. It all works pretty well.
It looks like they've talked about shared memory as important for efficiency, eg https://nim-lang.org/araq/concurrency.html (from back in 2013 apparently, and I don't know if it's a "canonical" project view or not) says:
> For real CPU efficiency on commodity hardware shared memory is unavoidable. Message passing doesn't cut it and ultimately doesn't address the same problems. (http://www.yosefk.com/blog/parallelism-and-concurrency-need-...) Also shared mutable memory is unavoidable in a systems programming context.
(I agree with that statement, fwiw.)
It sounds like they haven't built support for shared memory yet; correct? and as this Isolated construct is also in progress, I think there's basically no threading support in Nim yet?
Are they still intending to build shared memory as well as Isolated? Is it intended to be memory-safe (as in the Rust terminology) or not?