Feedback on Átila's Vision for D

[John Belmonte]

On Saturday, 19 October 2019 at 20:22:21 UTC, Sebastiaan Koppe 
wrote:
> https://vorpus.org/blog/notes-on-structured-concurrency-or-go-statement-considered-harmful/
>
> Oh that is actually pretty nice. The nursery idea reminds me a 
> bit of the coroutineScope in Kotlin. Makes a lot of sense.

Kotlin has a good structured concurrency implementation.  Scopes 
can be configured to use either a single OS thread (for UI, or 
simply to make concurrency easier to reason about and avoid the 
need for explicit locking and an entire class of race 
conditions), or multiple OS threads with various mapping 
strategies.  It's also a good example of what minimum support is 
needed from the language, vs. what can exist in the coroutine 
library.

Interestingly, the team working on Kotlin's experimental 
coroutine library stumbled on structured concurrency 
independently.  Martin Sústrik's defined it first (and made the 
libdill C implementation), which Nathaniel Smith greatly expanded 
on with his article and Python library.  A great characteristic 
of these people is that they want to work together to improve the 
state of the art, and aren't competitive with respect to their 
implementations 
(https://trio.discourse.group/t/structured-concurrency-kickoff/).

Rust appears to be going down the wrong concurrency path.  
Meanwhile C++ structured concurrency experiments have started 
(https://github.com/lewissbaker/cppcoro/, 
https://www.youtube.com/watch?v=1Wy5sq3s2rg).  It's either an 
opportunity for D, or a chance to fall behind...

The "founders" are very open to reviewing and consulting on 
getting structured concurrency right in other languages.  It 
would just take some mutual openness by D's stewards to have an 
honest look at where D is at and how it can move forward.