Gaming Hacks

Make Your IF NPCs Talk

Sass, growl, flirt, threaten, and cajole players.

A good writer can say a lot with a few words. One of the best tricks in interactive fiction is make players do exactly what you want them to do while maintaining the illusion that they have free will. Nowhere is this more evident than in NPC conversations.

Ideally, your NPCs should drop hints, help solve puzzles, and converse with, and ocasionally bedevil, players. How do you predict what players will say? How do you know how to respond? In general, you don’t, but there are a few tricks to make your NPCs seem like living, thinking beings.

Detailing NPC Conversation

Inform comes with a few built-in methods of talking to NPCs. The centerpiece of the default conversational model is the Ask verb. Let’s make this our means of chatting with the access controller. The game’s parser will take a command such as ask the access controller about the token, toss out the articles, figure out that the operative verb is ask, set the variable noun to controller, and then, as the key part, place the word token into the variable second. If you type ask the access controller about oatmeal, the word oatmeal goes into the variable second, even though there is no oatmeal object in the game. This makes conversation trivial to implement. Add this to the controller’s life block:

Ask: switch (second) { 'id', 'identity', 'token', 'tokens': if (token has general) "~YES, TOKEN WAS ACCEPTABLE!~ the access controller barks. ~YOU MAY PROCEED!"; ...