peek

        # Enumerator.peek

(from ruby core)
---
    e.peek   -> object

---

Returns the next object in the enumerator, but doesn't move the internal
position forward.  If the position is already at the end, StopIteration
is raised.

See class-level notes about external iterators.

### Example

    a = [1,2,3]
    e = a.to_enum
    p e.next   #=> 1
    p e.peek   #=> 2
    p e.peek   #=> 2
    p e.peek   #=> 2
    p e.next   #=> 2
    p e.next   #=> 3
    p e.peek   #raises StopIteration