A Blizzard Community Representative slipped few details of the map editor in Starcraft 2.  Recently, Rob Pardo mentioned how the single player would have special features for map makers and modders.

Drysc: “StarCraft IIs editor features a proprietary scripting language that is based largely on C with some special parameters specific to the game. Of course, for most users, they will have access to the more user friendly Trigger Editor which will allow beginner and intermediate map designers to make advanced maps without having to learn the particular details of the scripting language. We’ll release further information about the world editor as we move forward.”