So, Infocom source code is now uploaded to Github. Most people don’t speak or want to speak the language it’s written in, ZIL (Zork Implementation Language). You can browse through it and kind of suss out what’s being done when and the choices made over the course of time.
There are many games in the repository. To know more about the genesis of such games, here is information from Zork I, one of the first games of the ZIL generation:
Zork I is a 1980 interactive fiction game written by Marc Blank, Dave Lebling, Bruce Daniels and Tim Anderson and published by Infocom.
Further information on Zork I:
Explanatory text from the repo
What is this Repository?
This repository is a directory of source code for the Infocom game “Zork I” (and many others), including a variety of files both used and discarded in the production of the game. It is written in ZIL (Zork Implementation Language), a refactoring of MDL (Muddle), itself a dialect of LISP created by MIT students and staff.
The source code was contributed anonymously and represents a snapshot of the Infocom development system at time of shutdown – there is no remaining way to compare it against any official version as of this writing, and so it should be considered canonical, but not necessarily the exact source code arrangement for production.
Basic Information on the Contents of This Repository
It is mostly important to note that there is currently no known way to compile the source code in this repository into a final “Z-machine Interpreter Program” (ZIP) file. There are .ZIP files in some of the Infocom Source Code repositories but they were there as of final spin-down of the Infocom Drive and the means to create them is currently lost. (See “Third-Party Tools” below)
Throughout its history, Infocom used a TOPS20 mainframe with a compiler (ZILCH) to create and edit language files – this repository is a mirror of the source code directory archive of Infocom but could represent years of difference from what was originally released.
In general, Infocom games were created by taking previous Infocom source code, copying the directory, and making changes until the game worked the way the current Implementor needed. Structure, therefore, tended to follow from game to game and may or may not accurately reflect the actual function of the code.
There are also multiple versions of the “Z-Machine” and code did change notably between the first years of Infocom and a decade later. Addition of graphics, sound and memory expansion are all slowly implemented over time.
What is the Purpose of this Repository
This collection is meant for education, discussion, and historical work, allowing researchers and students to study how code was made for these interactive fiction games and how the system dealt with input and processing. It is not considered to be under an open license.
Researchers are encouraged to share their discoveries about the information in this source code and the history of Infocom and its many innovative employees.
If you are interested in working with ZIL, there is a set of tools for doing so here via Jesse McGrew. It includes a ZIL to ZAP compiler, a ZAP to binary Z code assembler, a text adventure library for writing games in ZIL, a source code port for Adventure and other tools.
PS If you’re an Infocom fan, see thee Internet Archive collection of papers here.
Do you recall Adventure, Zork, Hitchhiker’s Guide to the Galaxy, Leather Goddess of Phobos, etc? Let us know your thoughts in the comments below.