Inform
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Inform is a design system for interactive fiction, created in 1993 by Graham Nelson.

Overview

The Inform system properly consists of two major components: the Inform compiler, which generates story files from Inform source code, and the Inform library, a suite of software which handles the most difficult work of parsing the player's input and keeping track of the world model. The name Inform also refers to the Inform programming language that the compiler understands.

The Compiler

The Inform compiler generates files in Z-code (also called story files) from Inform source code. These files can then be run by any Z-code interpreter -- that is, by any program which properly emulates the Z-code virtual machine. Because there is at least one such interpreter for nearly every major and minor platform, this means that the same Z-code file can be run on a multitude of platforms with no alterations.

A version of the Inform compiler also exists that is capable of generating files for the Glulx virtual machine, which removes many of the limitations of the Z-machine. However, the Glulx virtual machine is not as widely ported.

Although Inform and the Z-Machine were originally designed with the Interactive Fiction genre in mind, a large number of other programs have been developed, including a BASIC interpreter, a Tetris game, and a version of the game Snake.

The Programming Language

Here is an example of Inform source code:

[ Main;
    print "Hello, world!^";
];

The Library

The Inform system also contains the Inform library, which automates nearly all of the most difficult work involved in programming interactive fiction; specifically, it includes a parser that makes sense of the player's input, and a world model that keeps track of such things as objects (and their properties), rooms, doors, the player's inventory, etc.

Notable Games Developed in Inform

• Curses, by Graham Nelson, was the first major game written in Inform, and is considered a classic of the form.
  
• Galatea, by Emily Short is probably the most detailed and effective implementation of an NPC in the medium.
  
• Photopia, by Adam Cadre, is generally credited as being the first truly puzzleless work of interactive fiction. Its appearance was a pivotal point in the history of the medium. (External Link)
• So Far, by Andrew Plotkin. Set a precedent for the integration of story, puzzle design, and player expectations in interaction fiction.

Further Reading

• The bible of Inform is Graham Nelson's excellent Inform Designer's Manual: it is a tutorial, a manual, and a technical document rolled into one. It is freely available online at Inform's official website, and a printed edition has been published by the Interactive Fiction Library. (ISBN 0-9713119-0-0)
• TADS is another interactive fiction design system that is comparable to Inform in terms of power, flexibility, portability, and popularity. Another well -regarded system is Hugo, though it is not nearly as widely-used as either TADS or Inform.

External Links

• Official web site: http://www.inform-fiction.org/
• An excellent Inform FAQ is available.
• Many Inform tools, examples, and library files are available at the Interactive Fiction Archive.

The original article can be found at: http://en.wikipedia.org/wiki/Inform.
All text is available under the terms of the GNU Free Documentation License.