- Ordered sets classes:

  Set::Infinite - An object representing recurrences, multiple spans, etc. TODO

  Set::Recurrence - An object representing a recurrence  TODO

- Functional versions of some of the above classes:

  Set::Recurrence::Functional  TODO

- Internal classes

  Set::Infinite::Functional

TESTING

  pugs -I../Test/lib -Ilib/Span/lib -Ilib t/test-name-here
