Tally
Tally
-- a class designed to hold tally results, i.e., multisets.
Operations:
Tally ** Tally
-- Cartesian product
Tally + Tally
-- sum
Tally - Tally
-- difference
Tally ? Tally
-- comparison
Tally _ Thing
-- access
tally
-- tally the elements of a list
toList
-- a list of the elements
sum Tally
-- add the elements
product Tally
-- multiply the elements