Chris Crawford on Interactive Storytelling (46 page)

The same goes for games. The verb counts for games of the early 1980s were generally lower than 10, perhaps because of the simple nature of the joysticks used for input. The only inputs possible were left, right, up, down, and the “fire” button: five verbs. Since then, games have become more complex and verb counts have grown, but in general, the verb counts of today’s games seldom exceed 30 and usually average about 15.

No matter how you design it, interactive storytelling requires hundreds or even thousands of verbs. Consider the verb count in this bit of fiction:

Alas, poor Yorick! I
knew
him, Horatio: a fellow of infinite jest, of most excellent fancy; he hath
borne
me upon his back a thousand times. And now how abhorred in my imagination it
is
! My gorge
rises
at it. Here
hung
those lips that I have
kiss’d
I
know
not how oft. Where
be
your gibes now, your gambols, your songs, your flashes of merriment that
were
wont to
set
the table on a roar? Not one now to
mock
your own grinning–quite chap-fall’n? Now
get
you to my lady’s chamber, and
tell
her, let her
paint
an inch thick, to this favor she must
come
;
make
her
laugh
at that.

This single short soliloquoy, just eight lines of text, has 12 different verbs. It constitutes less than half a percent of the entire play; clearly the play as a whole
boasts hundreds to thousands of different verbs. Interactive storytelling engines must be capable of handling such large verb counts.

With low verb counts, designers can craft each verb individually, writing custom code for each one. This method worked fine when you could count your verbs on your fingers, but when you start needing your toes to count, things became more difficult. A program such as Microsoft Word is an intricate maze of code, requiring the efforts of hundreds of programmers, yet its complexity causes it to break with depressing regularity. The difficulty of managing hundreds of custom-coded verbs has restrained software designers. Storybuilders, however, cannot evade the monster; their work requires managing thousands of verbs. You simply must dispense with the notion of custom-designing every verb. You need a more generalized approach, something more abstract that allows you to create, design, and program thousands of verbs.

The first step in creating a generalized system of verb handling is to design a data structure for Verbs. You need a general-purpose table of properties that define each Verb. Here are some variables that might belong in such a table:

Note
: Henceforth, I’ll be contracting “Direct Object” to “DirObject.”

Name
: A simple text label for the Verb.

Import
: A number indicating how newsworthy this Verb is.

TimeToPrepare
: The amount of time required to elapse from the time the Actor decides to execute the Verb until execution begins. Although most Verbs require zero
TimeToPrepare
, a few might require some. For example, if an Actor decides to poison someone, some time might be required to get the poison. An Actor wanting to hop into bed with another Actor requires a moment to remove clothing.

TimeToExecute
: The amount of time required to carry out the Verb. Again, most Verbs require just a moment to execute, but a few have extended execution periods—for example,
GoJogging
,
BakeCake
, or
BuildBoat
.

Audience
: Every Verb has certain requirements for the presence or absence of other Actors. Most of the time, the DirObject must be located with the Subject, but in a few cases the reverse is true. For example, should the Subject be hatching some dark plan aimed at the DirObject, the Subject most definitely wants to carry it out without the presence of the DirObject.
MixPoison
,
DigGrave
, or
DonWeddingDress
are three Verbs that require the absence of a DirObject.

Some Verbs require the privacy of Subject and DirObject and, therefore, the absence of others. Verbs used in romantic situations are often like this. A few Verbs require the presence of a third party, either as a witness or as party to the action. And of course, there are also specifications for whether other Actors present can witness a Verb being carried out. All told, I have identified 10 specific situations that require particular combinations of people present or absent:

MentalState
: This situation represents an action inside the Subject’s mind; others can be present but won’t be able to witness it.

AnyAudience
: The most common situation; the Actor executing the Verb doesn’t care about the presence or absence of any other person.

RequireWitness
: The Subject will not execute the Verb unless some third party is present to witness the Event.

SubjectOnly
: The Subject wants to carry out the Verb in secret and must be alone.