Iterables and Iterators

• Iterable
• objects that can produce an Iterator
• have a .iterator method
• interpolate in list context (except when in scalar container)
• List, Array, LoL

• Iterator
• inherit from Iterable
• objects that perform iteration
• have a .reify method to produce values
• usually wrapped by a List
• ListIter - iterates elements of a List
• MapIter - lazily applies a block to a List
• GatherIter - handles gather/take list generation