Manual:DIL Manual/exit to

exit_to

The exit_to field is a read-only array field available on room units that provides access to the destination rooms for each direction exit.

Syntax

room.exit_to[direction]

Field Access

Access	Type	Description
room.exit_to[direction]	unitptr	The destination room for the specified direction

Parameters

Parameter	Type	Description
direction	integer	Direction index (NORTH, EAST, SOUTH, WEST, UP, DOWN)

Return Value

Returns a unit pointer to the destination room:

• unitptr - The destination room unit if an exit exists in that direction
• null - If no exit exists in that direction
• fail - If the room unit is invalid or the direction index is out of range

Direction Constants

The direction parameter accepts any of the following constants defined in values.h or vme.h:

Constant	Value	Description
NORTH	0	North direction
EAST	1	East direction
SOUTH	2	South direction
WEST	3	West direction
UP	4	Up direction
DOWN	5	Down direction

Examples

Basic Exit Check

dilbegin check_exits(room : unitptr);
code
{
   if (room.exit_to[NORTH] != null) {
      send("There is an exit to the north.");
   }
   if (room.exit_to[SOUTH] == null) {
      send("There is no exit to the south.");
   }
   quit;
} dilend

Clan Teleport Example

dilbegin clan_move(i:integer);
code
{

act("

$1n vanishes.

",A_HIDEINV,self, null, null, TO_ROOM); act("

You are teleported.

", A_SOMEONE,self, null, null, TO_CHAR);

   link(self, self.outside.exit_to[i]);

act("

$1n appears from thin air.

",A_HIDEINV, self, null, null, TO_ROOM);

   exec("look", self);
   quit;
} dilend

Exit Validation

dilbegin validate_exit(room : unitptr, direction : integer);
code
{
   if (direction < 0 or direction > 5) {
      send("Invalid direction.");
      quit;
   }
   
   if (room.exit_to[direction] != null) {
      send("Exit leads to: " + room.exit_to[direction].title);
   } else {
      send("No exit in that direction.");
   }
   quit;
} dilend

Room Light Check

dilbegin check_room_light(room : unitptr);
var
   dir : integer;
   buff : string;
code
{
   buff := "Exits: ";
   for (dir := 0; dir < 6; dir := dir + 1) {
      if (room.exit_to[dir]) {
         buff := buff + room.exit_to[dir].title + "
";
      }
   }
   send(buff);
   quit;
} dilend

Error Handling

The field performs comprehensive validation:

• 'Room validation - Ensures the unit is a valid room type
• 'Direction validation - Checks that the direction index is between 0 and MAX_EXIT
• 'Exit existence - Returns null if no exit exists in the specified direction
• 'Type validation - Returns fail if accessed on non-room units

Note: The C implementation shows that the function uses is_in() to validate the direction range and ROOM_EXIT() macro to access the exit data structure.

Usage Notes

• This field is read-only - you cannot change exit destinations through DIL
• Only available on room units (UNIT_ST_ROOM type)
• Always check for null return values before using the destination room
• The field is commonly used for navigation, teleportation, and room validation
• Use with exit_names[] and exit_info[] for complete exit management
• Direction constants are defined in values.h and vme.h header files

Related Fields

• exit_names - Array of exit name strings for each direction
• exit_info - Array of exit flag bits for each direction
• roomflags - Room property flags
• movement - Room movement type

See Also

• unitptr - Unit pointer data type
• link - Function to move units between rooms
• findroom - Function to find rooms by name
• UNIT_ST_ROOM - Room unit type constant