The documentation in the "Tasks in Toit" section indicates that the language has facilities for asynchronous data exchange between tasks. If I understand correctly, then two classes from the monitor package: Channel and Mailbox provide this opportunity. Unfortunately, I didn't find examples of using these classes, so I ask you to give at least the simplest example of the implementation of two tasks:
Thanks in advance, MK
Here's an example of the first part, using Channel. This class is useful if you have a stream of messages for another task.
import monitor
main:
// A channel with a backlog of 5 items. Once the reader is 5 items behind, the
// writer will block when trying to send. This helps avoid unbounded memory
// use by the in-flight messages if messages are being generated faster than
// they are being consumed. Decreasing this will tend to reduce throughput,
// increasing it will increase memory use.
channel := monitor.Channel 5
task:: message_generating_task channel
task:: message_receiving_task channel
/// Normally this could be looking at IO ports, GPIO pins, or perhaps a socket
/// connection. It could block for some unknown time while doing this. In this
/// case we just sleep a little to illustrate that the data arrives at random
/// times.
generate_message:
milliseconds := random 1000
sleep --ms=milliseconds
// The message is just a string, but could be any object.
return "Message creation took $(milliseconds)ms"
message_generating_task channel/monitor.Channel:
10.repeat:
message := generate_message
channel.send message
channel.send null // We are done.
/// Normally this could be looking at IO ports, GPIO pins, or perhaps a socket
/// connection. It could block for some unknown time while doing this. In this
/// case we just sleep a little to illustrate that the data takes a random
/// amount of time to process.
process_message message:
milliseconds := random 1000
sleep --ms=milliseconds
print message
message_receiving_task channel/monitor.Channel:
while message := channel.receive:
process_message message
Here is an example of using Mailbox. This class is useful if you have a task processing requests and giving responses to other tasks.
import monitor
main:
mailbox := monitor.Mailbox
task:: client_task 1 mailbox
task:: client_task 2 mailbox
task --background:: factorization_task mailbox
/// Normally this could be looking at IO ports, GPIO pins, or perhaps a socket
/// connection. It could block for some unknown time while doing this. For
/// this example we just sleep a little to illustrate that the data arrives at
/// random times.
generate_huge_number:
milliseconds := random 1000
sleep --ms=milliseconds
return (random 100) + 1 // Not actually so huge.
client_task task_number mailbox/monitor.Mailbox:
10.repeat:
huge := generate_huge_number
factor := mailbox.send huge // Send number, wait for result.
other_factor := huge / factor
print "task $task_number: $factor * $other_factor == $huge"
// Factorize a number using the quantum computing port.
factorize_number number:
// TODO: Use actual quantum computing instead of brute-force search.
for i := number.sqrt.round; i > 1; i--:
factor := number / i
if factor * i == number:
return factor
// This will yield so the other tasks can run. In a real application it
// would be waiting on an IO pin connected to the quantum computing unit.
sleep --ms=1
return 1 // 1 is sort-of a factor of all integers.
factorization_task mailbox/monitor.Mailbox:
// Because this task was started as a background task (see 'main' function),
// the program does not wait for it to exit so this loop does not need a real
// exit condition.
while number := mailbox.receive:
result := factorize_number number
mailbox.reply result