3.3. One-way connections

| Chapter 3: Things |

| 3.3. One-way connections

Connections are ordinarily two-way, but do not have to be. One of the map connections in the Mammoth Cave simulation was made by the sentence:

> The Debris Room is west of the Crawl.

Besides reading this sentence at face value, Inform also deduced that the Crawl was probably meant to be east of the Debris Room: in other words, that the path between them is a two-way one. When Inform makes guesses like this, it treats them as being less certain than anything explicitly stated in the source. Inform will quietly overturn its assumption if information comes to hand which shows that it was wrong. That might happen in this case if another sentence read:

> The Hidden Alcove is east of the Debris Room.

These two sentences are not contradictory: Inform allows them both, simply accepting that the world is more complicated than it first assumed. There are relatively few situations where Inform has to make educated guesses, but when it does, it tries always to follow Occam's Razor by constructing the simplest model world consistent with the information in the Source text.

We can even explicitly make a route which turns around as it leads between two rooms:

> West of the Garden is south of the Meadow.

Finally, if we want to establish a route which cannot be retraced at all, we can specify that a particular direction leads nowhere:

> East of the Debris Room is nowhere.

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| Example Port Royal 2 Another part of Port Royal, with less typical map connections. |
RB

8
| Example The Unbuttoned Elevator Affair A simple elevator connecting two floors which is operated simply by walking in and out, and has no buttons or fancy doors. |
RB

This is very simple. The interior of the elevator is a single room, but which is mapped east of both of its termini. The reverse map connection, west from the elevator, can only go to a single room, and that's what determines which floor the elevator is on. "The Unbuttoned Elevator Affair" UNCLE Headquarters is a room. "The steel nerve-center of the free world's battle against the Technological Hierarchy for the Removal of Undesirables and the Subjugation of Humanity. Being against technology, we have only a very simple elevator to the east." Del Floria's Tailor Shop is a room. "Only trained anti-THRUSH agents recognise the booth in the east wall as a secret elevator." The Secret Elevator is east of UNCLE Headquarters. The Secret Elevator is east of Del Floria's Tailor Shop. After going to the Secret Elevator: say "The doors automatically close, there is a rush of motion, and they open again."; if UNCLE Headquarters is mapped west of the Secret Elevator, now Del Floria's Tailor Shop is mapped west of the Secret Elevator; otherwise now UNCLE Headquarters is mapped west of the Secret Elevator; continue the action. Test me with "east / west / east / west".

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