Function iterator 

pub fn iterator<'a, T: Elem, const N: usize>(
    v: &'a mut dyn Iterator<Item = &'a T>,
) -> Result<Expr<'a, T, N>, &'static str>

Array identity operation via iterator.

This allows interoperation with non-contiguous array formats. Note this method is significantly slower than consuming an array or slice, even if the iterator is over a contiguous array or slice. Whenever possible, it is best to provide the contiguous data directly.

Panics

• If the length of the iterator is not known exactly