Chapter 29. The Rezrov Infocom Game Interpreter

Michael Edmonson

Interactive fiction, or IF to its devotees, is a genre of text-based computer games. IF games present a virtual environment to the player, and respond to commands typed by the player. For example:

West of House
You are standing in an open field west of a white house,
with a boarded front door.

There is a small mailbox here.

>open mailbox
Opening the small mailbox reveals a leaflet.

IF traces its heritage to the early days of computer gaming. The first game was known simply as Adventure, or Colossal Cave, in which the player explored a mammoth underground cavern, collecting treasures and solving puzzles. Adventure caused a sensation when it arrived on the scene in the 1970’s, but the game had a very limited vocabulary and could only accept simple commands. Inspired, a group of friends at MIT set about developing a new game with a vastly expanded vocabulary and the ability to understand complete sentences. This game became known as Zork, and its developers went on to form a company called Infocom.

Zork was originally developed on a DEC PDP-10 mainframe, a very expensive computer few people had access to. To bring the game to a wider audience, Zork’s programmers wanted to find a way to make it run on the fledgling home computers of the time. Further complicating matters was the fact that home computers were much rarer than they are today, and there was a much wider variety of brands. To maximize the size of their market, ...

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