The Inform Designer’s Manual

Inform is a system for creating adventure games, and this is the book to read about it. It translates an author’s textual description into a simulated world which can be explored by readers using almost any computer, with the aid of an ‘‘interpreter’’ program. Inform is a suite of software, called the ‘‘library’’, as well as a compiler. Without the library, it would be a major undertaking to design even the smallest game. The library has two ingredients: the ‘‘parser’’, which tries to make sense of the player’s typed commands, and the ‘‘world model’’, a complex web of standard rules, such as that people can’t see without a source of light. Given these, the designer only needs to describe places and items, mentioning any exceptional rules that apply. (‘‘There is a bird here, which is a normal item except that you can’t pick it up.’’) This manual describes Inform 6.21 (or later), with library 6/9 (or later), but earlier Inform 6 releases are similar. Since its invention in 1993, Inform has been used to design some hundreds of works of interactive fiction, in eight languages, reviewed in periodicals ranging in specialisation from XYZZYnews (www.xyzzynews.com) to The New York Times (see Edward Rothstein’s ‘Connections’ column for 6 April 1998). It accounts for around ten thousand postings per year to Internet newsgroups. Commercially, Inform has been used as a multimedia games prototyping tool. Academically, it has turned up in syllabuses and seminars from computer science to theoretical architecture, and appears in books such as Cybertext: Perspectives on Ergodic Literature (E. J. Aarseth, Johns Hopkins Press, 1997). Having started as a revival of the then-disused Infocom adventure game format, the ‘‘Z-Machine’’, Inform came full circle when it produced Infocom’s only text game of the 1990s: ‘Zork: The Undiscovered Underground’, by Mike Berlyn and Marc Blank. Nevertheless, Inform is not the only system available, and the intending game designer should shop around. This author at least has long admired the elegance of Mike Roberts’s Text Adventure Development System (TADS).