namespace;
include rt;

// closures: calls through values, shared captures, state in a capture,
// nested captures, closures passed as arguments and returned from functions
fn apply(f, x) { return f(x); }
fn twice(g, x) { return g(g(x)); }
fn sq(x) { return x * x; }
word.u make(n) {
	let h = fn(x) { return x * n; };
	return u*h;
}
fn main() {
	let k = 10, m = 3;
	let add = fn(x) { return x + k * m; };
	rt.put_n(add(1)); rt.put_c(10);
	rt.put_n(apply(add, 5)); rt.put_c(10);
	let none = fn() { return 42; };
	rt.put_n(none()); rt.put_c(10);
	let n = 0;
	let bump = fn(d) { n = n + d; return n; };
	rt.put_n(bump(2)); rt.put_c(10);
	rt.put_n(bump(5)); rt.put_c(10);
	rt.put_n(n); rt.put_c(10);
	let a = 2;
	let outer = fn(x) {
		let inner = fn(y) { return y + a + x; };
		return inner(100);
	};
	rt.put_n(outer(7)); rt.put_c(10);
	let base = 5;
	let scale = fn(i) { return i * base; };
	let s = 0, i = 0;
	while (i < 4) { s = s + scale(i); i++; }
	rt.put_n(s); rt.put_c(10);
	let c = 3;
	let plus = fn(v) { return v + c; };
	rt.put_n(twice(plus, 1)); rt.put_c(10);
	rt.put_n(sq(4)); rt.put_c(10);
	let total = 0, j = 0;
	while (j < 3) {
		let kk = j;
		let g = fn(x) { return x + kk; };
		total = total + g(10);
		j++;
	}
	rt.put_n(total); rt.put_c(10);
	let f = make(4);
	rt.put_n(f(5)); rt.put_c(10);
	let h = 1;
	let frozen = fn(x) { return x + h; };
	h = 100;
	rt.put_n(frozen(1)); rt.put_c(10);
	return 0;
}