Luna

Luna is an interpreted, dynamically typed scripting language implemented as a C++20 module. It uses a recursive descent parser and an AST-walking interpreter.

Type System

Luna supports the following value types:

Type	Description	Example
None	Represents the absence of value	none
Boolean	Logical true or false	true, false
Integer	64-bit signed integer	42
Number	64-bit floating point	3.14159
Symbol	Interned identifier string	#identifier
String	Text sequence	"hello"
List	Ordered generic collection	[1, 2, "a"]
Table	Key-value associative array	{ x: 10, y: 20 }

Syntax

Variable Declaration

Variables are declared using the var keyword.

var x = 100;
var message = "Hello";

Control Flow

Luna provides standard branching and looping constructs.

// Conditional
if (x > 50) {
    x = x - 1;
} else {
    x = x + 1;
}

// Loop
while (x > 0) {
    if (x == 10) break;
    if (x == 20) continue;
    x = x - 1;
}

Functions

Functions are first-class citizens. They support optional parameters with default values.

fn add(a, b: 1) {
    return a + b;
}

// Usage
var result = add(10); // b defaults to 1

Error Handling

Errors are structural exceptions that propagate up the call stack.

try {
    throw "An error occurred";
} catch (e) {
    // 'e' contains the thrown value
}

Reflection and Casting

The language includes operators for runtime type inspection and conversion.

var x = 10;

// Type Check
if (x is integer) {
    // Conversion
    var s = x as string;
}

// Type Query
var t = typeof(x); // returns #integer