noct

A tree-walking interpreter for a dynamically typed programming language, written in C++23.

• Types: nil, booleans, numbers (double), strings, functions, classes, instances
• Variables: lexical scoping with shadowing (var x = 1;)
• Expressions: arithmetic, comparison, equality, logical (and/or), ternary (? :), unary, prefix/postfix ++/--
• Control flow: if/else, while, for (desugared to while), break
• Functions: named functions, lambdas (fn(params) { body }), closures, recursion
• Classes: single-dispatch OOP with this, constructor via init, dynamic fields
• Built‑ins: print, maybe (50/50 random boolean)
• Comments: // line and /* block */

class Node {
  fn init(val) {
    this.val = val;
    this.next = nil;
  }
}

class List {
  fn init() {
    this.head = nil;
  }

  fn push(val) {
    var node = Node(val);
    node.next = this.head;
    this.head = node;
  }

  fn print() {
    var cur = this.head;
    while (cur != nil) {
      print cur.val;
      cur = cur.next;
    }
  }
}

var list = List();
list.push(3);
list.push(2);
list.push(1);
list.print();

# Build
./generate.sh

# Run a script
./run.sh path/to/script.noct

cmake --build build && build/NoctTests

or

cd build && ctest --output-on-failure

• CMake ≥ 3.20
• Ninja build system
• fmt (external, found via find_package)
• C++23 compiler

MIT