pyr by example

Concurrency

Pyr has built-in green threads and channels. Spawn creates lightweight tasks scheduled cooperatively by the runtime, and bounded channels provide safe communication between them.

spawn creates a green thread (task). Tasks are cooperatively scheduled.

 
fn worker(id: int) {
  println("worker {id} done")
}

channel(n) creates a bounded channel. .send() and .recv() block when full or empty.

 
fn producer(ch, n: int) {
  for i in range(n) {
    ch.send(i)
  }
}

await_all waits for multiple tasks and collects their results into an array.

 
fn compute(x: int) -> int = x * x

fn main() {
  spawn { worker(1) }
  spawn { worker(2) }

  ch = channel(4)
  spawn { producer(ch, 4) }

  for i in range(4) {
    println(ch.recv())
  }

  results = await_all(
    spawn { compute(3) },
    spawn { compute(4) }
  )
  println(results)
}
 
$ pyr run concurrency.pyr
worker 1 done
worker 2 done
0
1
2
3
[9, 16]