package patricia-tree

The type of generic/heterogeneous keys

A unique identifier for values of the type. Usually, we use a fresh counter that is increased to give a unique id to each object. Correctness of the operations requires that different values in a tree correspond to different integers.

Must be injective, return only positive values, and ideally fast

Polymorphic equality function used to compare our keys. It should satisfy (to_int a) = (to_int b) ==> polyeq a b = Eq