Dead Souls and Mappings A mapping is an organization of data that makes it possible to associate data elements together in a human-understandable way. For a builder with no coding experience, mappings can be a challenge to understand. However, you must grasp at least the very basics of this data type in order to be an effective builder. The Dead Souls mudlib has three kinds of objects that normally have other objects inside of them: NPC's, rooms, and containers. When the mud loads one of these, often they are intended to have stuff inside them already, such as a teasure chest with jewels, an orc with an axe, or a room with an orc guarding a treasure chest. In such a circumstance, each of these objects is loaded from a file that contains information about the contents of the object. This is called the object's inventory, and it is determined by the SetInventory directive in that file. An example of a room's SetInventory directive might look a little like this: SetInventory( ([ "/domains/town/npc/fighter" : 1, "/domains/town/npc/orc" : "growl", "/domains/town/obj/chest" : 1, ]) ); You can tell it's a mapping right away from the square brackets: [ ]. What this mapping does is identify a fighter, orc, and chest as objects to be put into the room when it is loaded. If we wanted 2 fighters, we would have put a 2 instead of a 1 there. What the "growl" value does is provide that orc with a command to perform when it appears. You could just have a number there, to specify the number of orcs desired. That's it. It's that simple. A mapping consists of pairs of data, separated by a colon (the : symbol). The part to the left is called a key, and the part to the right is called the value. A mapping can contain more than one of these pairs, each separated from the other by a comma. As a non-coding builder, what you need to know is that when the creation system asks you for a key, it is possible for keys to have multiple values, like this: ({"room","here","area"}) : "This area looks very nice." In this example, the mapping element is part of the SetItems directive. When you modify a room's description items, you will be asked to enter keys until you are done. This allows you to enter multiple words that respond in the same way. For example, "examine wall" and "examine concrete wall" should both provide the same description. However, in the case of inventory, only one key is valid, so make sure you only enter one.