namespace;
include rt;

// ownership in practice: a list owns its boxes. nothing here calls free;
// everything is released at the end of the block that owns it.
.u box(v) { let b = rt.new(1); b[0] = v; return b; }
.u mklist(cap) { let l = rt.new(cap + 1); l[0] = 0; return l; }
// item arrives as an owned parameter and moves into the borrowed list
void push(.m l, .d item) { l[l[0] + 1] = d*item; l[0] = l[0] + 1; return; }
void show(.m l) {
	let i = 1;
	rt.put_c('[');
	while (i <= l[0]) { if (i > 1) rt.put_c(' '); rt.put_n(l[i][0]); i++; }
	rt.put_c(']');
	return;
}
.u squares(n) {
	let l = mklist(n), i = 0;
	while (i < n) {
		let b = box(i * i);
		push(l, b);
		i++;
	}
	return l;
}
void main() {
	let before = rt.live_objects();
	{
		let l = squares(6);
		show(l); rt.put_c(10);
		rt.put_s("live: "); rt.put_n(rt.live_objects() - before); rt.put_c(10);
	}
	rt.put_s("after the block: "); rt.put_n(rt.live_objects() - before); rt.put_c(10);
	return;
}