An interactive fiction programming language, created by Graham Nelson in 1993 and now one of the most popular IF development systems. Inform is particularly notable in that it compiles to code for the Z-machine, the same virtual machine used by Infocom. More recent versions of the Inform compiler optionally produce code for the more powerful and flexible virtual machine Glulx.
Inform is portable across many hardware platforms. Interpreters for z-code exist for nearly every computer system ever designed and Glulx interpreters exist for most major operating systems currently in use.
Graham Nelson announced the first release of Inform (with no version number, but considered "Inform 1" in retrospect) on RAIF in May 1993:
Subject: Announcement: INFORM From: Graham Nelson Date: Sun, 9 May 1993 18:20:53 GMT Infocom game story files are as near to a universal format as we have for interactive fiction games, but until now it has been very difficult to construct them, and I am not aware that anyone has previously created them outside of Infocom itself. I have written such a compiler, called "Inform", the ANSI C source of which is public domain. It is not a marvellously well-written program, but it does work, and it is documented. (Usenet post via Google)
This version generated only Z-code V3 game files. Nelson also released the first version of Curses on this day, as Inform's first game.
Inform 2 was announced in June:
Subject: Second release of Inform From: Volker Blasius Date: Fri, 11 Jun 1993 20:51:29 GMT My game "Curses", plodding along in the footsteps of the classics, has now picked up one more Infocom trait: the original has been superseded, after mere months have passed, by Release 8, serial number 930603. The old Release 7 thus becomes a collector's item. (I wouldn't hold your breath waiting for it to become valuable, though.) ... In addition, "Inform", the compiler which produced "Curses" and which is freely available to anyone who wants to write an Infocom story-file for themselves, has been re-released in a much more usable and efficient form. Although there are only a few new features (see the manual), many little bugs have been corrected and the code has been made more portable (it is in ANSI C) and much more efficient. It used to require about 1M of workspace, and now consumes 75K, for instance. The source code contains commentary to help anyone porting the program to their own machines. It should be quite feasible to run Inform on a modest PC. (Usenet post via Google)
Summary of Inform Variations
- Inform 6
- Inform 7
- Triform - alternate Inform library (still in beta as of January 2005).
Tips and Tutorials
There are a number of editors meant to make writing Inform code simpler and easier. They can automatically highlight or format code, generate basic code for classes, and other handy functions.
- IF-Archive list of editors (including Inform editors, and editors for other development systems as well)
- Inform Explorer
- Roger Firth's list of IF editors