Mutexes in OpenSCAD

In OpenSCAD, we don’t have direct equivalents for mutexes or concurrency, as it’s primarily a 3D modeling scripting language. However, we can demonstrate a similar concept using modules and functions to manage state. Here’s an example that mimics the behavior of the original code as closely as possible in OpenSCAD:

// Container to hold our counters
module Container() {
    counters = [["a", 0], ["b", 0]];
    
    // Function to increment a counter
    function inc(name, counters) = 
        [for (counter = counters) 
            if (counter[0] == name) 
                [counter[0], counter[1] + 1] 
            else 
                counter
        ];
    
    // Simulate multiple increments
    counters = inc("a", inc("a", inc("b", counters)));
    
    // Display the results
    echo(str("Counters: ", counters));
}

// Main execution
Container();

In this OpenSCAD script:

1. We define a Container module that holds our state and logic.

2. Inside Container, we initialize our counters as a list of lists, mimicking the map in the original code.

3. We define an inc function that takes a counter name and the current state of counters, and returns a new state with the specified counter incremented.

4. To simulate multiple concurrent increments, we chain multiple calls to inc. This is a simplified representation of the concurrent operations in the original code.

5. Finally, we use echo to display the results, similar to the fmt.Println in the original code.

To run this script:

$ openscad -o output.scad mutexes.scad

This will execute the script and output the results to the console:

ECHO: "Counters: [["a", 2], ["b", 1]]"

Note that OpenSCAD doesn’t support true concurrency or mutexes. This example demonstrates a functional approach to state management, which is more aligned with OpenSCAD’s paradigm. The state is immutable, and each operation creates a new state rather than modifying an existing one.

While this doesn’t perfectly replicate the behavior of the original Go code, it provides a similar concept of managing and updating state in a controlled manner within the constraints of OpenSCAD’s language features.