util.rs

// ...

pub trait VecUtil<Elem> {
        pub fn grouped<'r>(&'r self, n: uint) -> ~[&'r [Elem]];
}

impl<'self, Elem> VecUtil<Elem> for &'self [Elem] {
	fn grouped<'r>(&'r self, n: uint) -> ~[&'r [Elem]] {
		if self.is_empty() { return ~[]; }
		let mut res = vec::with_capacity((self.len()-1) / n + 1);
		for uint::range_step(0, self.len(), n as int) |i| {
			res.push(self.slice(i, i+n));
		}
		res
	}
}