A succession of values.
ObjectRange can model a range of any value that implements a
method (which links that value to its "successor").
ObjectRange mixes in
Enumerable, which makes ranges very versatile.
It takes care, however, to override the default code for
achieve better efficiency.
ObjectRange does provide a constructor, the preferred way to obtain
a range is to use the
$R utility function, which is strictly equivalent
(only way more concise to use).