How to make a map with two keys?

[Malaxiz]

I want to be able to search for just one key, like this:

Sprite.at["Stone"] == Sprite.at[0]

Sprite.at["Grass"] == Sprite.at[1]

Is this possible, or should I be using another method?

[Cubbi]

boost has multi-index containers ( http://www.boost.org/doc/libs/release/libs/multi_index/doc/index.html ), or you could put one together yourself

[Smac89]

have you tried std::map(tree) or std::unordered_map(hashmap)?

http://www.cplusplus.com/reference/map/map/
http://www.cplusplus.com/reference/unordered_map/unordered_map/