# Aliases
type Receiver = fn() -> any
type Sender = fn(any)

fn new_channel() -> (Sender, Receiver) {
    queue := []

    fn send(n: any) {
        queue.push(n) # mutate in-place
    }

    fn recv() -> any | nil {
        queue.pop()
    }

    (send, recv)
}

(send, recv) := new_channel()

(
    send:,
    recv:,
)