3.5. Doors, Staircases, and Bridges

| Chapter 3: Place |

| 3.5. Doors, Staircases, and Bridges

Inform's "door" kind provides for a tangible thing which comes between one room and another. A door can be open or closed, and openable or not: it can be locked or unlocked, and lockable or not. Here we create a conventional door, a natural gap in the rocks, and a (fixed in place) wooden ladder:

> The fire door is an open door. The fire door is east of the Projection Booth and west of the Fire Escape.
> The narrow crevice is an open unopenable door. The crevice is east of the Col du Prafleuri and west of Rocky Knoll Above Arolla.
> The wooden ladder is an open unopenable door. The ladder is above the Stableyard and below the Hay Loft.

Most doors are visible from both sides: they are single objects but present in two rooms at once, which raises a number of complications. Inform normally uses the same description looking from each way, which is not very interesting: When? and Whence? demonstrate neat ways to describe the two sides differently, and Whither? adds the option for the player to refer to doors as "the west door" and "the east door" automatically.

Neighbourhood Watch goes further by making a door behave differently on each side: from the "outside" you need a key, but "inside" it opens on a latch. Finally, Garibaldi 1 shows how to access information about the two sides of a door.

Higher Calling demonstrates doors which automatically open as needed: though using the Inform extension Locksmith by Emily Short is probably easier and better. Elsie, conversely, demonstrates a door that closes one turn after the player has opened it.

Certain complications apply when characters other than the player have to see and interact with doors that exist in other rooms. Wainwright Acts demonstrates the syntax needed to handle this technically quirky situation.

Something Narsty and Hayseed provide a "staircase" kind useful for vertically arranged, always-open doors like staircases and (fixed in place) ladders.

One Short Plank implements a precarious plank bridge across a chasm as an open unopenable door.

See Windows for climbing through a window from one room to another

See Ropes for portable connections between rooms, much of the development of which could be adapted to handle portable ladders. "Doors" are never allowed to move

See Magic (Breaking the Laws of Physics) for a hat that lets the player walk through closed doors

See Modifying Existing Commands for ways to allow the player to unlock with a key he isn't currently holding

63
| Example When? A door whose description says "...leads east" in one place and "...leads west" in the other. |
WI

65
| Example Whence? A kind of door that always automatically describes the direction it opens and what lies on the far side (if that other room has been visited). |
WI

308
| Example Whither? A door whose description says where it leads; and which automatically understands references such as "the west door" and "the east door" depending on which direction it leads from the location. |
WI

128
| Example Higher Calling All doors in the game automatically attempt to open if the player approaches them when they are closed. |
WI

150
| Example Elsie A door that closes automatically one turn after the player opens it. |
WI

Suppose we want to create an automated door of the sort that closes when it isn't in use. A convenient way is to write a rule that fires "every turn when the sliding door was open". This will be true only if the door was open at the beginning of the turn: if the player just opened it this turn, it stays open, and if it was already closed, it stays closed. Thus: "Elsie" The axis-ward is a direction. The opposite of axis-ward is hub-ward. Understand "aw" or "axisward" as axis-ward. The hub-ward is a direction. The opposite of hub-ward is axis-ward. Understand "hw" or "hubward" as hub-ward. The Ship's Bridge is a room. The sliding door is a door. It is axis-ward from Bridge and hub-ward from C Deck. The initial appearance is "There is a door in this wall[if closed] -- or at least, the potential for a door, since currently it is sealed, distinguishable from the rest of the wall only by the warning stripes on its surface[end if]." Every turn when the sliding door was open: now the sliding door is closed; if the player can see the sliding door: say "The sliding door slips back into place, sealing the wall as though there had never been a breach." After opening the sliding door: say "You press the appropriate buttons, and a section of wall slides away." Test me with "open door / look / enter door / z".

23
| Example Neighborhood Watch A locked door that can be locked or unlocked without a key from one side, but not from the other. |
WI

21
| Example Garibaldi 1 Providing a security readout device by which the player can check on the status of all doors in the game. |
WI

236
| Example Wainwright Acts A technical note about checking the location of door objects when characters other than the player are interacting with them. |
WI

42
| Example Something Narsty A staircase always open and never openable. |
WI

88
| Example Hayseed A refinement of our staircase kind which can be climbed. |
WI

106
| Example One Short Plank A plank bridge which breaks if the player is carrying something when he goes across it. Pushing anything over the bridge is forbidden outright. |
WI

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