use super::*;
type _1 = Next<Zero>;
pub trait Length {
type Output;
}
impl<H, T> Length for Cons<H, T>
where
T: Length,
<T as Length>::Output: Num,
{
type Output = <<T as Length>::Output as PeanoAdd<_1>>::Output;
}
impl Length for Nil {
type Output = Zero;
}