bimap is:module

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.

Partly invertible finite maps. Time complexities are given under the assumption that all relevant instance functions, as well as arguments of function type, take constant time, and "n" is the number of keys involved in the operation.

Bimap between Word8 an an arbitrary (ordered) type. Values of type Word8Bimap have to be constructed carefully to contain values for all 256 Word8 values, or the API will not be safe to use.