Post Position

This is the fourth in a series of posts about my interactive fiction system, Curveship.

I was recently asked to elaborate on the difference between nn (the research system I developed during my dissertation work at the University of Pennsylvania) and Curveship.

The most important difference is that nn is a research system that I used for making some advances related to computer science, computational linguistics, and narratology. The system was developed to prove certain points; it was used only by yours truly to implement narrative and text generation ideas and to run demos.

It worked pretty well for this. Using nn, I developed a new representation for the order of actions, one that can be used flexibly in text generation. I put together a string-with-slots representation used in templates, one that is much less cumbersome to use than a general abstract syntax representation. And I worked out how a focalizer world (now called a “concept”) can model an actor’s theory about the “real” or “actual” world that is central to an interactive fiction.

That’s not to say that you’d want to pick up this system, though, and start writing games in it. While nn in 2007 had all the basic components of an IF system (a parser, the ability to save an restore games, the ability to model a world), they were not all ready for prime time, because my development work was focused on trying to answer particular research questions.

So, I took the nn code and began working on a new project, Curveship. I wanted to release a system that was developed with other IF authors, other AI researchers, and other teachers of narrative theory and electronic literature in mind. Curveship is getting close to being this system – within a few months, I hope, I will get it to that point, with the help of a group of people, the Curveship crew, who are testing and commenting on pre-release versions.

Concretely, there are three main sorts of differences. First, bugs in nn that my limited use of the system didn’t expose have been fixed – and more will be. Second, there are improved capabilities that didn’t relate to my research goals, but which are important to IF authors. These range from better parsing and clarification (disambiguation) to better ways of formatting text to better capabilities for simulating physical aspects of the world. Finally, I have impeoved the interface, which includes changing the names of some components of the system. What used to be a “plan for narrating” is now “spin.” What I called “existents” (a perfectly nice but abstruse term from narratology) are now, more simply, called “items.” To avoid confusion, I even changed the name of the “Narrator” module, because “narrator” is a narrative function and a parameter that can be set within the system. This module is now called the “Teller.” There have been other name changes and a great deal of refactoring, some writing of docstrings, and other improvements to make the Curveship code more understandable and manipulable to those who want to get into it. The way string-with-slots templates are written has changed, too, as has the way items and actions are created.

The discussion of reply structures, focalizer worlds, and similar aspects of the system in previous publications (such as my dissertation) remains largely applicable to Curveship. But because Curveship is being developed with an eye toward a new group of author/programmers, researchers, and teachers, there have been many changes beyond the parts of nn that implement those core research contributions. Even some of publications and talks about Curveship from recent months have names for components that are now different and mention the old style string-with-slots formalism. That’s one of the reasons I’ve started in on this series of posts.

This is the third in a series of posts about my interactive fiction system, Curveship.

Before I start descending into detail, I’ll explain why I think Curveship is a big deal.

Curveship does the usual work of an interactive fiction system when it comes to simulating a world: There are discrete rooms that make up the fiction’s locations, actors can inhabit and wander around these rooms, and things can sit in them, be taken and carried off or otherwise moved around. Items can change state, so that a lamp, for instance, can be turned on and off. Items can go into or onto other items, if they allow it. None of this is surprising; plenty of interactive fiction development systems already do all of it very well.

Hypertexts don’t do that. Hypertexts, including Web hypertexts but also pieces in HyperCard, Storyspace, Twine, and similar systems, present a structured document in which some phrases are hooked up to other pages. They might have guard fields or other pieces of code, but at their most essential, they are really strange surfaces of text, with phrases connected in an unusual topology.

Nothing’s wrong with hypertext. If you want to create an unusual language surface, to link pages together into a curious structure, it’s clearly the form to use. The play and connection of language can be intriguing and relevant. You can make a compelling literary work in this form, as several people have done.

But interactive fiction systems allow something else. You can put a simulated world underneath the text that people see. This lets you create different types of literary systems, which can be nice: Several people have created interactive fiction systems that are compelling literary pieces and that couldn’t have been realized as hypertexts.

In an important way, Curveship is to interactive fiction what interactive fiction is to hypertext. Just as interactive fiction added a new and significant model – a model of a simulated world – Curveship adds a model of the telling, of the narrating, of the way that the simulated world is represented in language. Curveship adds spin, as in the spinning of a tale and as in Spin Alley.

Curveship can leave actions out of the narrative, can reorder actions in the narrative to create flashbacks and flashforwards and retrograde narration and narration by category, can narrate at greater or lesser length, and can represent several actions in one statement or repeat the narration of a single action several times. The system can tell about what is happening in the simulated world from the perspective of any specified actor, based on that actor’s knowledge and perceptions, or it can narrate from a global perspective. It can tell about what has happened in the past just as easily as it can represent a current action.

The system is able to do this because it models every action that happens in the world, just as existing IF systems model every item. First-order representations of actions differentiate Curveship from other IF systems. And on that of that, a complete text generation system has been built, allowing for grammatical changes that follow from high-level narrative parameters – the spin.

Consider The Odyssey. Why is it interesting? Why has it shaped world culture and remained memorable for thousands of years? Yes, lots of interesting stuff happens in it. But the way it is told is also tremendously compelling – Odysseus listening to the song of his own exploits, shielding his eyes and weeping, being identified as the great hero, and then going on to tell the next part of the story in his own voice. That’s as fascinating a part of The Odyssey as is the encounter with the Cyclops or the slaying of the suitors. And the telling surely becomes more important in contemporary literature. Is Lolita really more interesting because of what happens or because of how it is told? What about Ulysses? To the Lighthouse?

Curveship’s modeling of the telling adds to the significant power that IF already provides by way of a model of a simulated world. Just as IF adds a simulated world to hypertext, Curveship adds control over the telling (that is, it adds spin) to the simulated world.

Those who want to create strange surfaces of text will want to work in hypertext. Those who want to have a simulated world will probably use an existing IF system. For those who are interested in varying the telling, as many great authors have done in oral, written, typed, and word-processed literature, it will be best to use a simulated world and spin: Curveship.