Closing Channels in OpenSCAD

In OpenSCAD, we don’t have direct equivalents for channels or goroutines. However, we can simulate a similar concept using functions and global variables. Here’s an example that demonstrates a similar workflow:

// Global variables to simulate channels
jobs = [];
done = false;

// Function to simulate sending jobs
function send_job(job) = 
    concat(jobs, [job]);

// Function to simulate receiving a job
function receive_job() = 
    len(jobs) > 0 ? [jobs[0], true] : [undef, false];

// Function to simulate the worker
module worker() {
    while (!done) {
        job = receive_job();
        if (job[1]) {
            echo(str("received job ", job[0]));
            jobs = [ for (i = [1:len(jobs)-1]) jobs[i] ];
        } else {
            echo("received all jobs");
            done = true;
        }
    }
}

// Main function
module main() {
    for (j = [1:3]) {
        jobs = send_job(j);
        echo(str("sent job ", j));
    }
    echo("sent all jobs");
    
    worker();
    
    more_jobs = receive_job();
    echo(str("received more jobs: ", more_jobs[1]));
}

main();

In this OpenSCAD example:

1. We use global variables jobs and done to simulate channels.

2. The send_job function adds a job to the jobs list, simulating sending a job to a channel.

3. The receive_job function retrieves a job from the jobs list, simulating receiving from a channel. It returns a pair [job, more], where more is true if a job was available.

4. The worker module simulates the worker goroutine. It processes jobs until done is set to true.

5. In the main module, we send three jobs, then call the worker, and finally check if there are more jobs.

To run this program, save it as closing_channels.scad and open it in OpenSCAD. The output will be displayed in the console window.

Note that OpenSCAD is primarily a 3D modeling language and doesn’t support true parallel processing or channels. This example is a conceptual translation that mimics the behavior of the original program using OpenSCAD’s available features.

The idea of closed channels doesn’t have a direct equivalent in OpenSCAD, but we’ve simulated it by checking if the jobs list is empty.