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

"1691" Thames Street End is a room. If we check out a map of historic Port Royal, we find that Thames Street End bends around the northwest tip of the peninsula and becomes the (very) roughly north/south Fisher's Row. We can't put Fisher's Row south of Thames Street End, though, because Lime Street is already going that way. So instead, let's have a map connection that bends around from west to north: West of Thames Street End is north of Fisher's Row. Now continuing west along Thames Street, or north along Fisher's Row, will bring us around the corner in question. Asymmetric map connections should be used carefully. They're good for representing the layout of the real world, which tends not to be laid out on a convenient square matrix, but if exits are not described clearly they can be disorienting for the player. So let's be sure to make things clear: The description of Fisher's Row is "A waterfront street that runs south towards Chocolata Hole, where the small craft are harboured. It also continues north around the tip of the peninsula from here, turning into the east-west Thames Street." Meanwhile, suppose Fort James is in a prominent position, raised a bit from its surroundings; maybe the player should be able to go down from there, as well as south, to get to Thames Street End. Thames Street End is down from Fort James. Thames Street End is south from Fort James. But we don't want the upward direction to work: Up from Thames Street End is nowhere. Test me with "n / d / u / w / e / n / s".

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| 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

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