An implementation of bidirectional maps between values of two key
types. A
Bimap is essentially a bijection between subsets of
its two argument types.
Each element of the left-hand type is associated with an element of
the right-hand type, and vice-versa, such that the two mappings are
inverses. Deleting an element will cause its twin to be deleted, and
inserting a pair of elements will cause any overlapping bindings to be
deleted.
Most functions implicitly consider the left-hand type to be the key,
and the right-hand type to be the value. Functions with an
R
suffix reverse this convention, treating the right-hand type as the
key and the left-hand type as the value.