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Async Module

The async module provides basic asynchronous functionality for Neutron, enabling non-blocking operations and concurrent execution patterns.

Importing the Module

use async;

Functions

async.run(function)

Executes a function asynchronously in a background context and returns a task object representing the async operation.

Parameters: - function - The function to execute asynchronously

Returns: - An object representing the async task

Example: 

use async;

var task = async.run(fun() {
    // Some time-consuming operation
    return "async result";
});

say("Task started: " + task);

async.await(task)

Waits for an async task to complete and returns its result.

Parameters: - task - The async task object returned by async.run()

Returns: - The result of the completed async operation

Example: 

use async;

var task = async.run(fun() {
    return 42;
});

var result = async.await(task);
say("Async result: " + result);

async.sleep(milliseconds)

Pauses execution for the specified number of milliseconds.

Note

Currently, this function holds the VM lock during sleep to ensure thread safety, which means it will block other Neutron threads from executing bytecode.

Parameters: - milliseconds - Number of milliseconds to sleep

Returns: - true when sleep completes

Example: 

use async;

say("Before sleep");
async.sleep(1000);  // Sleep for 1 second
say("After sleep");

async.timer(function, delay_ms)

Executes a function after a specified delay.

Parameters: - function - The function to execute after the delay - delay_ms - Delay in milliseconds before executing the function

Returns: - An object representing the async task (can be awaited)

Example: 

use async;

var task = async.timer(fun() {
    say("Timer executed!");
}, 2000);  // Execute after 2 seconds

say("Timer scheduled");
async.await(task); // Wait for timer to complete

Examples

Basic Async Execution

use async;

var task = async.run(fun() {
    async.sleep(500);
    return "Hello from async!";
});

var result = async.await(task);
say(result);  // Output: "Hello from async!"

Timing Operations

use async;

say("Starting...");

// Schedule delayed execution
async.timer(fun() {
    say("Delayed execution completed");
}, 1000);

// Continue with other work
async.sleep(1500);
say("Main execution completed");

Sleep Example

use async;

say("Starting long operation...");
async.sleep(2000);  // Simulate 2 second wait
say("Operation completed");

Notes

  • The async module uses native OS threads for concurrent execution.
  • A Global Interpreter Lock (GIL) ensures thread safety for VM operations.
  • async.run spawns a new thread that acquires the GIL only when executing Neutron code.
  • async.await and async.sleep release the GIL, allowing other threads to run.
  • This model allows for true parallelism for blocking I/O operations or native code that releases the GIL, but Neutron bytecode execution is serialized.
  • The implementation provides a foundation for async programming in Neutron, with potential for enhancement in future versions