I will stick with (and highly recommend) a standard way to communicate maps from map generator to the rest of the game.
The map generator returns an "intmap" - that is, a 2-dimensional array of integers, where each type of terrain is indicated by a different number. (0 is open floor, 1 is wall, 2 is standard door, etc)
The game, in turn, is responsible for taking an intmap and doing whatever it does to convert it to whatever map representation the game uses internally.
Decoupling map generation from map representation is useful, IMO, because the specifics of map representation are very likely to change during development (f'rexample I hacked in flags for directional lighting this week), and you don't want to have to revise every map generator every time that happens. Just the appropriate changes to the conversion function and all the existing map generators are applicable.