Chris Crawford on Interactive Storytelling (47 page)

SubjectAndDirObjectOnly
: The Subject and DirObject both must be present, but must have privacy.

AllAudience
: This is a special case for an Event so sensational—the 9/11 attacks, for example—that it is, in effect, instantly made known to all Actors.

ThreeParty:
An Event requiring the presence of three parties: Subject, DirObject, and a third Actor.

FourParty:
An Event requiring the presence of four parties: Subject, DirObject, and two other Actors.

CheekByJowl:
This is a special case in which two Actors are together in a public place, whispering together. Their actions can’t be witnessed by anybody except a person deliberately spying on them.

AnybodyBut:
Another rare case, it requires Subject and DirObject, but a specified third Actor may not be present. This situation would arise when, say, Subject is insulting the third Actor to DirObject.

These are the variables most likely to be of value in any verb-based interactive storytelling engine. My own engine uses many more variables, but they are specific to that engine and not worth exploring in this general discussion.

When a Verb is executed, it’s part of an
Event
. My use of the term “Event” is very close to its normal use, except that, for purposes of interactive storytelling, Events must be reducible to computer expression. The real world is full of complex and tricky events that defy computational expression, so the requirement of making Events fit inside a computer expression does seem to restrict your creative freedom. But if Michelangelo had to fit his work on the ceiling of the Sistine Chapel, you can work within the constraints of the computer, right? The data structure for Events looks something like this:

What are all those “something or others”? It should be pretty obvious from the way I’ve written it that they are things like subjects, direct objects, adjectives, adverbs, and prepositional phrases. For the moment, I’ll keep it as simple as possible:

Subject Verb

This data structure is clean and simple, but it’s too constrained for most use. Yes, in a few situations this structure works adequately, as in these examples:

Sammy slept.

Mary fretted.

The fruit ripened.

Face it, however: This kind of sentence just won’t handle most situations, but it does bring out an important point. The first two sentences look fine, but that third sentence has “fruit” for a subject. That’s a tad peculiar. Yes, we use sentences like this all the time, but for the purposes of drama, requiring that the subject of every sentence be an Actor is more appropriate. In other words, inanimate objects can’t do things.

But how would you say “The fruit ripened” if fruit can’t be the subject? Doesn’t this make it impossible to record events that are outside the control of any Actor? What about natural events, acts of God, or accidents?