Comment by brabel

> especially with the new IO mechanism which allows supper efficient code that looks good whether it's implemented single-threaded, multi-threaded or just via an event loop!

I had some trouble understanding how the async/await mechanism works:

  var foo_future = io.async(foo, .{args});
  defer if (foo_future.cancel(io)) |resource| resource.deinit() else |_| {}

  var bar_future = io.async(bar, .{args});
  defer if (bar_future.cancel(io)) |resource| resource.deinit() else |_| {}

  const foo_result = try foo_future.await(io);
  const bar_result = try bar_future.await(io);

My assumption is that calling io.async using an event loop implementation of IO, it will internally start a "task" (or whatever it should be called) and that the future is a handle to it. So far so good.

The part that I don't understand is what happens when you call future.await(io). Will the IO implementation somehow suspend the current function and resume once the future is resolved? If so, does that mean that every function in zig is a stackless coroutine?

the “(super) efficient” is not there yet. Io is still dynamic dispatch with multiple layers of indirection. afaik it’s slower than before.

the upcoming releases are expected to provide a solution to this “dispatch is comptime-known, but still dynamic” problem, and drop the loses in efficiency.

Maybe one day it'd be possible to use these new features, but I find myself using `.use_llvm = true` in my zig builds for stability and lesser tested targets.