3 ms·

Oh boy. Example 7 is a bit of a mindfuck. You get the returned string in both in await and cancel. Feels like this violates zig “no hidden control flow” princi

Oh boy. Example 7 is a bit of a mindfuck. You get the returned string in both in await and cancel. Feels like this violates zig “no hidden control flow” principle. I kinda see how it doesn’t. But it sure feels like a violation. But I also don’t see how they can retain the spirit of the principle with async code.

rdtsc 11mo ago
> Feels like this violates zig “no hidden control flow” principle. A hot take here is that the whole async thing is a hidden control flow. Some people noticed that ever since plain callbacks were touted as a "webscale" way to do concurrency. The sequence of callbacks being executed or canceled forms a hidden, implicit control flow running concurrently with the main control logic. It can be harder to debug and manage than threads. But that said, unless, Zig adds a runtime with its own scheduler and turns into a bytecode VM, there is not much it can do. Co-routines and green threads have been done before in C and C-like languages, but not sure how easily the would fit with Zig and its philosophy.
- throwawaymaths 11mo ago
  hidden control flow means no control flow occurs outside of function boundaries, keywords, short circuiting operators, or builtins. i believe there is a plan for a asyncresume and asyncsuspend builtins that show the actual sites where control flow happens.
- int_19h 11mo ago
  They have plans for multiple implementations including green threads and stackless.
  - rdtsc 11mo ago
    That's pretty neat. Thanks for pointing it out. The abstraction on top still async based and I agree it makes sense for Zig. But in general I don't like that abstraction. I like it when it's flipped around -- the abstraction is process/thread/green thread-like and sending messages or events around. Underneath it may involved having a few IO pollers with select/epoll/io_uring, a thread pool, etc. But the top level API doesn't handle promises, futures, callback, deferreds, etc. I am thinking of Go's goroutines, BEAM VM processes, or even plain threads or processes talking over the network or locally via queue.
HacklesRaised 11mo ago
hard for me to argue with your point but if the understanding is that cancellation causes early return of the function, then i suppose the signature is, eerrr, consistent?

rdtsc 11mo ago

> Feels like this violates zig “no hidden control flow” principle. A hot take here is that the whole async thing is a hidden control flow. Some people noticed that ever since plain callbacks were touted as a "webscale" way to do concurrency. The sequence of callbacks being executed or canceled forms a hidden, implicit control flow running concurrently with the main control logic. It can be harder to debug and manage than threads. But that said, unless, Zig adds a runtime with its own scheduler and turns into a bytecode VM, there is not much it can do. Co-routines and green threads have been done before in C and C-like languages, but not sure how easily the would fit with Zig and its philosophy.

throwawaymaths 11mo ago
hidden control flow means no control flow occurs outside of function boundaries, keywords, short circuiting operators, or builtins. i believe there is a plan for a asyncresume and asyncsuspend builtins that show the actual sites where control flow happens.
int_19h 11mo ago
They have plans for multiple implementations including green threads and stackless.
- rdtsc 11mo ago
  That's pretty neat. Thanks for pointing it out. The abstraction on top still async based and I agree it makes sense for Zig. But in general I don't like that abstraction. I like it when it's flipped around -- the abstraction is process/thread/green thread-like and sending messages or events around. Underneath it may involved having a few IO pollers with select/epoll/io_uring, a thread pool, etc. But the top level API doesn't handle promises, futures, callback, deferreds, etc. I am thinking of Go's goroutines, BEAM VM processes, or even plain threads or processes talking over the network or locally via queue.

HacklesRaised 11mo ago

hard for me to argue with your point but if the understanding is that cancellation causes early return of the function, then i suppose the signature is, eerrr, consistent?