using Gee;
 
private class RangeIterator : Object, Iterator<int> {
 
    private Range range;
    private int current;
 
    public RangeIterator (Range range) {
        this.range = range;
        this.current = range.from;
    }
 
    public bool next () {
        return this.current <= this.range.to;
    }
 
    public int get () {
        return this.current++;
    }
}
 
public class Range : Object, Iterable<int> {
 
    public int from { get; private set; }
    public int to { get; private set; }
 
    public Range (int from, int to) {
        assert (from < to);