libdill VS CspChan

libmill (https://github.com/sustrik/libmill) and libdill (https://github.com/sustrik/libdill) should be similar and probably mentioned.

As far as I understand the differences between CspChan and libmill might be that libmill also implements lightweight tasks (coroutines) and everything that goes with it (IO multiplexing, async timers, etc), while CspChan uses OS threads?

I saw this in 2017. Unfortunately, not much activity now. https://github.com/sustrik/libdill/commits/master

Might be fun to play with, but I wouldn't rely on it. Generally, better off with libuv for existing projects or Rust for greener fields where lifetimes are checked and safe concurrency is much easier.

I've updated the paper and removed the SELECT, CLOSE and CLOSED procedures as discussed.

I still think a close feature which - in contrast to Go - would just signal all waiting threads and abandon communication could be useful. I implemented this in the C library I use for experiments: https://github.com/rochus-keller/CspChan

> the proposal for it to take a timeout, which could then be detected via execution of ELSE?

It could still be added in future, e.g. as an additional parameter to SEND or RECEIVE, but in a similar way to CLOSE it makes things more complicated, and there is an alternative solution with a separate thread sending after a delay a over a channel which receives in a WITH statement where the candidate channel waits.

> have you considered asking Dr Wirth for feedback?

I have qualms about bothering him with this in his well-deserved retirement, especially as he has demonstrated with Oberon-07 in which direction he would develop the language (see also https://oberon-lang.github.io/2021/07/16/comparing-oberon+-w...).