PARSER??? by Stu Galley (The Status Line; Spring 1989; page 2) Copyright 1989 (c) Infocom Transcribed by Graeme Cree What is a parser anyway, and why should it matter to you? Almost any dictionary can answer the first question, and I'm here to tell you about the second one. As the dictionary states, a parser is something that takes apart a sentence, word by word, and determines what the words mean, and then what the sentence means. If you ever diagrammed a sentence for an English class, then you were parsing. But it's a lot easier for YOU to parse English than it is for a machine, because you've had a lot more practice at it, and you started life with a certain natural ability to do it. At Infocom, I've been working on a program that will parse your commands and pass on their "meaning" to an interactive story. This program is a part of ZORK ZERO, ARTHUR, and SHOGUN, as well as future Infocom products that may want to understand more complex sentences. In a way, I'm like the recording engineer for your favorite rock album, because my job is to make sure that the artists' talent comes through to you as clearly as possible. If the guitarist wants more reverb...I mean if the implementor wants adverbs to work in his story, then I provide it. The better I do my job, the less you notice it! Almost anyone can write a simple parsing program, just as almost anyone can make simple recordings on their boom box. A simple parser could parse any two-word sentence, by calling the first word a verb and the second one a noun. If it didn't know the verb, or if the noun wasn't the name of something in the room, then it would give up. Some simple adventure games work exactly that way. Until now, Infocom's thirty-odd interactive stories have all used the parser that evolved from ZORK I. But each new story needed some new features in the parser, and so it grew more clever, but also harder to fix and improve. Eventually, we decided to build a new parser from scratch, using the theory of computational linguistics. (Technically speaking, we used an ATN algorithm with a LALR grammar and one-token look-ahead.) So what does this mean to you? It means that you can converse with our interactive fiction more simply than ever, and we can easily add features that you've never seen before. For example, ZORK ZERO notices if you seem to be having trouble with the parser, and it offers helpful suggestions, such as sample commands. And in SHOGUN, you can use a wider range of sentences, including statements and questions, to converse with the characters you'll meet. In the future, we may develop new kinds of products, able to "talk" with you about many topics; our interactive fiction could becomre much more than mazes and mysteries!