13.10. Defining new prepositions

| Chapter 13: Relations |

| 13.10. Defining new prepositions

The term preposition is used here, a little loosely, to mean anything which we add to the verb to be in order to talk about some relation or other. We have seen many examples already, such as:

> To be in - The ball is in the box.
> To be part of - The lever is part of the slot machine.

These are easier to create than verbs, because Inform already knows the wayward grammar of to be, so we need not give any of the principal parts. Otherwise, the method is exactly the same. Compare the definitions in the following:

> Suspecting relates various people to one person.

> The verb to suspect (he suspects, they suspect, he suspected, it is suspected, he is suspecting) implies the suspecting relation.

> The verb to be suspicious of implies the suspecting relation.

The result of this is that

> Hercule Poirot suspects Colonel Hotchkiss.
> Hercule Poirot is suspicious of Colonel Hotchkiss.

are exactly equivalent, and so are these two descriptions:

> somebody who suspects Colonel Hotchkiss
> somebody suspicious of Colonel Hotchkiss

While most prepositions are short ("in", "part of", "suspicious of"), they're free to be longer if need be ("very far away from"): the limit is 30 words, which should be ample.

We can also define verbs as auxiliaries, like so:

> The verb to be able to approach (he is approached) implies the approachability relation.

Now we can ask if Poirot "can approach" Hotchkiss, and so on. (Here again we need not spell out the other parts of the verb.)

231
| Example Swerve left? Swerve right? Or think about it and die? Building a marble chute track in which a dropped marble will automatically roll downhill. |
RB

232
| Example The Abolition of Love A thorough exploration of all the kinds of relations established so far, with the syntax to set and unset them. |
RB

233
| Example Beneath the Surface An "underlying" relation which adds to the world model the idea of objects hidden under other objects. |
RB

234
| Example Bogart Clothing for the player that layers, so that items cannot be taken off in the wrong order, and the player's inventory lists only the clothing that is currently visible. |
RB

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