package containers

An accessor for values of type 'a in any map. Values put in the map using a key can only be retrieved using this very same key.

Return a value that works for a given type of values. This function is normally called once for each type of value. Several keys may be created for the same type, but a value set with a given setter can only be retrieved with the matching getter. The same key can be reused across multiple maps (although not in a thread-safe way).