Non Blocking Channel Operations in OpenSCAD

Our first example demonstrates non-blocking operations in OpenSCAD. While OpenSCAD doesn’t have built-in concurrency or channel concepts, we can simulate similar behavior using functions and conditional statements.

// Simulate a channel-like structure
function create_channel() = [];

// Simulate a non-blocking receive
function try_receive(channel) = 
    len(channel) > 0 ? [true, channel[0]] : [false, undef];

// Simulate a non-blocking send
function try_send(channel, message) =
    len(channel) < 10 ? [true, concat(channel, [message])] : [false, channel];

// Main function to demonstrate non-blocking operations
function main() =
    let(
        messages = create_channel(),
        signals = create_channel()
    )
    let(
        // Non-blocking receive
        receive_result = try_receive(messages),
        _ = receive_result[0] 
            ? echo("received message", receive_result[1])
            : echo("no message received")
    )
    let(
        // Non-blocking send
        msg = "hi",
        send_result = try_send(messages, msg),
        _ = send_result[0]
            ? echo("sent message", msg)
            : echo("no message sent")
    )
    let(
        // Multi-way non-blocking select
        receive_message = try_receive(messages),
        receive_signal = try_receive(signals),
        _ = receive_message[0]
            ? echo("received message", receive_message[1])
            : receive_signal[0]
                ? echo("received signal", receive_signal[1])
                : echo("no activity")
    )
    0;

main();

In this OpenSCAD code, we simulate channel-like behavior and non-blocking operations:

1. We define functions to create a channel-like structure and perform non-blocking receive and send operations.

2. The try_receive function simulates a non-blocking receive. If a value is available in the channel, it returns [true, value]. Otherwise, it returns [false, undef].

3. The try_send function simulates a non-blocking send. If the channel is not full (we use a limit of 10 elements), it returns [true, updated_channel]. Otherwise, it returns [false, original_channel].

4. In the main function, we demonstrate non-blocking receive, send, and multi-way select operations using conditional statements and the echo function to print results.

5. The let expressions are used to create local bindings and perform operations sequentially.

When you run this OpenSCAD script, it will output:

ECHO: "no message received"
ECHO: "no message sent"
ECHO: "no activity"

This example demonstrates how to implement non-blocking operations in OpenSCAD, even though the language doesn’t have built-in concurrency features. The concept is simulated using functions and conditional statements to achieve similar behavior.