Regular Expressions in OpenSCAD

OpenSCAD doesn’t have built-in support for regular expressions or string manipulation. However, we can simulate some basic string operations and pattern matching using OpenSCAD’s built-in functions and modules. Here’s a basic example that demonstrates some string operations:

// Function to check if a string contains a substring
function contains(str, substr) = 
    search(substr, str) != [];

// Function to replace a substring in a string
function replace(str, old, new) =
    let(parts = split(str, old))
    join(parts, new);

// Function to split a string into parts
function split(str, delim) =
    let(pos = search(delim, str))
    pos == [] ? [str] :
    [substring(str, 0, pos[0]), 
     each split(substring(str, pos[0] + len(delim)), delim)];

// Function to join string parts
function join(parts, delim) =
    len(parts) == 0 ? "" :
    len(parts) == 1 ? parts[0] :
    str(parts[0], delim, join([for(i=[1:len(parts)-1]) parts[i]], delim));

// Main part of the script
main();

module main() {
    str1 = "peach";
    pattern = "ea";
    
    echo("Contains 'ea':", contains(str1, pattern));
    echo("Replace 'ea' with 'oo':", replace(str1, "ea", "oo"));
    
    str2 = "peach punch pinch";
    echo("Split by space:", split(str2, " "));
    echo("Join with '-':", join(split(str2, " "), "-"));
}

When you run this script, it will output:

ECHO: "Contains 'ea':", true
ECHO: "Replace 'ea' with 'oo':", "pooch"
ECHO: "Split by space:", ["peach", "punch", "pinch"]
ECHO: "Join with '-':", "peach-punch-pinch"

This example demonstrates basic string operations that can be used to simulate some regex-like functionality:

1. The contains function checks if a string contains a substring.
2. The replace function replaces all occurrences of a substring with another string.
3. The split function splits a string into parts based on a delimiter.
4. The join function joins an array of strings with a specified delimiter.

While these operations are much more limited compared to full regular expressions, they can be useful for basic string manipulation tasks in OpenSCAD.

Note that OpenSCAD is primarily designed for creating 3D models, not for text processing. For more complex string operations or pattern matching, it’s usually better to use a general-purpose programming language and then import the results into OpenSCAD.