There comes a point in many projects where there is a choice between adding yet another layer of maps of arrays and pulling in a serious database engine, many fail to stop and consider other available options. Arrays and maps are not the end of the story when it comes to data structures, there are more powerful general purpose abstractions available.
libc4life provides ordered composite key indexes with user specified key and value types and value semantics, based on binary searched maps. Indexes are optionally unique and/or hashed. Hashed indexes are ordered within slots and allow overriding the algorithm for assigning slots to keys.