Functions

fn dist(ax: num, az: num, bx: num, bz: num): num {
  let dx = bx - ax
  let dz = bz - az
  return sqrt(dx * dx + dz * dz)
}

• Declared with fn, at the top level only (no nesting, no closures in v0.1).
• Parameter types are required. The return type follows the parameter list after :; omit it for a void function.
• Declare before use (C-style): a function must appear above its first call. update/draw are called by the host, so their position doesn't matter relative to each other.
• Recursion works (fn fib(k: num): num { ... return fib(k-1) + fib(k-2) }).
• Calls are checked: wrong arity or argument types are compile errors that name the function and the argument number.

The frame contract

The engine looks up two functions by name each frame:

fn update(dt: num) { }   // simulation; dt in seconds
fn draw() { }            // rendering; 3D calls then 2D composites on top

Both are optional. Top-level statements run once at load — that is where you create meshes, load textures and sounds, and initialize state.

Returning values

A function with a declared return type must return expr on the paths that matter; falling off the end of a non-void function returns nil (avoid relying on this — v0.1 does not enforce full path coverage yet; see limits).

Multiple return values do not exist; return a value and use out-of-band state, or split into two functions (the Kora Night port's nearest_unlit() + dist2_to(i) pair is the worked example).