Messages

Every message consists of two parts: type and text. Both type and text are strings. The type of message has the form /str1/str2/.../strn. The text can be an arbitrary string.

The types of messages are organized into a hierarchy, much like the structure of files and directories. There are several predefined types of messages.

Message Types

/visual: The type of all messages that describe visual events, i.e., events that can be seen.
/audio: The type of all messages that describe audio events, i.e., events that can be heard.
/smell: The type of all messages that describe scents and smells.
/invisible: The type of all /visual messages generated by invisible objects, such as ghosts and invisible wizards. Audio events generated by invisible objects have type /audio.
/psycho: The type of messages that describe thoughts and telepathic messages.
/system: System-specific messages. They are used for debugging purposes.
/$group: A message can be limited to a group, if its type is preceeded by /$group. For example, an audio event that is only detected by wizards would have type /$wizard/audio.
/!name: A message can be limited to an object, if its type is preceeded by /!name, where name is the name of the object that should receive the message (as returned by query_name()).

There are also message types specific to classes, races, clubs, etc. See the following sections:

Composite messages

The two main functions that deal with messages are receive_msg() and request_msg(). Function receive_msg() takes either one or two arguments. When it takes two arguments, they are type and text. When it takes just one argument, the argument is a composite message.

A composite message is a list of the form

 ({ "type1", "text1", "type2", "text2", ..., "typeN", "textN" })

When an object receives a composite message, it goes through the mapping, and receives only the first message for which it has a defined handler. It ignores the other messages.

Consider the following composite message:

({ "/!frege/audio", "Dino tells you: Hello.\n",
   "/!dino/audio",  "You tell Frege: Hello.\n",
   "/audio",        "Dino tells Frege something.\n"
})

When this message is emitted in the room which contains Frege and Dino, Frege will hear "Dino tells you: Hello.", Dino will hear "You tell Frege: Hello.", and everybody else will hear "Dino tells Frege something.".

Note: It would seem more sensible to define a composite message as a mapping. However, in a mapping the order is not necessarily preserved. Here, the order is crucial.