Recursion in OpenSCAD

Our example demonstrates recursion in OpenSCAD. Here’s the translated code and explanation:

// This fact function calls itself until it reaches the
// base case of fact(0).
function fact(n) = 
    n == 0 ? 1 : n * fact(n-1);

// Main function to demonstrate the usage
function main() = [
    fact(7),
    fib(7)
];

// Fibonacci function using recursion
function fib(n) = 
    n < 2 ? n : fib(n-1) + fib(n-2);

// Print the results
echo(main());

OpenSCAD supports recursive functions. Here’s a classic example of factorial calculation using recursion.

The fact function is defined recursively. It calls itself until it reaches the base case of fact(0).

In OpenSCAD, we don’t have a separate main function like in some other languages. Instead, we can define a main function that returns an array with our results.

OpenSCAD doesn’t have built-in printing functionality like some other languages. Instead, we use the echo() function to output values to the console.

Closures, as used in some other languages, are not directly supported in OpenSCAD. However, we can define separate functions to achieve similar functionality. Here, we’ve defined a fib function to calculate Fibonacci numbers recursively.

To run this script, save it as a .scad file and open it in the OpenSCAD application. The console output will show:

ECHO: [5040, 13]

This output represents the factorial of 7 (5040) and the 7th Fibonacci number (13).

Remember that in OpenSCAD, functions are primarily used for mathematical operations and generating geometry. The language is designed for creating 3D models, so its approach to programming concepts like recursion is tailored to that purpose.