Directionclass
Directions. Each direction is represented by an instance of Direction.
A Direction object encapsulates information about a travel direction. By using an object to represent each possible travel direction, we make it possible for a game or library extension to add new custom directions without having to change the basic library.
Modified in
en_us.t[3053]:
The English-specific modifications for directions.
class Direction : object
Superclass Tree (in declaration order)
Direction
` object`
Subclass Tree
Direction
CompassDirection
RelativeDirection
ShipboardDirection
VerticalDirection
Global Objects
(none)
Summary of Properties
allDirections dirProp sortingOrder
Summary of Methods
defaultConnector initializeDirection initializeDirectionClass sayArriving sayDeparting
Properties
allDirections
A master list of the defined directions. We build this automatically during initialization to include each Direction instance. Any operation that wants to iterate over all possible directions can run through this list.
By using this master list to enumerate all possible directions rather than a hard-coded set of pre-defined directions, we can ensure that any new directions that a game or library extension adds will be incorporated automatically into the library simply by virtue of the existence Direction instances to represent the new directions.
dirProp
The link property for the direction. This is a property pointer that we use to ask an actor’s location for a TravelConnector when the actor attempts to travel in this direction.
sortingOrder
Our sorting order in the master list. We use this to present directions in a consistent, aesthetically pleasing order in listings involving multiple directions. The sorting order is simply an integer that gives the relative position in the list; the list of directions is sorted from lowest sorting order to highest. Sorting order numbers don’t have to be contiguous, since we simply put the directions in an order that makes the sortingOrder values ascend through the list.
Methods
defaultConnector (loc)
The default TravelConnector when an actor attempts travel in this direction, but the actor’s location does not define the dirProp property for this direction. This is almost always a connector that goes nowhere, such as noTravel, since this is used only when a location doesn’t have a link for travel in this direction.
initializeDirection ( )
Initialize. We’ll use this routine to add each Direction instance to the master direction list (Direction.allDirections) during pre-initialization.
initializeDirectionClass ( )
Class initialization - this is called once on the class object. We’ll build our master list of all of the Direction objects in the game, and then sort the list using the sorting order.
sayArriving (traveler)
describe a traveler arriving from this direction
sayDeparting (traveler)
describe a traveler departing in this direction
TADS 3 Library Manual
Generated on 5/16/2013 from TADS version 3.1.3