Confusion: A MDL interpreter
(or, "How to Fit a Small Program into a Large Machine")
For those poor souls still stuck in dawn of IF history, I present
"Confusion" -- a MDL interpreter which works just well enough to play
the original Zork all the way through. The original Zork isn't for the
faint of heart, and neither is Confusion; it is only available in
source form, with minimal instruction (which follows).
Confusion is written in C++, though about 99% is pure C. To build it, you
will need the Boehm-Demers-Weiser conservative garbage collector for
Some Linux distros have this as a package, called "gc-dev" or
similar. For the Mac, you'll need what is at this writing the very latest
version (7.2alpha2), for Linux, 6.8 appears to work. For Windows... I
recommend running Linux in a virtual machine. It might build under
cygwin, but I wouldn't bet on it.
Once you have the GC, a simple "make" will build the interpreter.
The Zork sources, somewhat modified for the limitations of this
interpreter, are available at
To play Zork, unpack this directory, change directory to the new
"mdlzork" directory", run the interpreter with the parameter "-r
MDL/MADADV.SAVE" e.g. "../confusion-src/mdli -r MDL/MADADV.SAVE".
You should be at the white house:
$ ../confusion-src/mdli -r MDL/MADADV.SAVE
This Zork created July 6, 2009.
West of House
This is an open field west of a white house, with a boarded front
There is a small mailbox here.
A rubber mat saying 'Welcome to Zork!' lies by the door.
The HELP, DOC and INFO commands do not work, as I do not have those files.
I have played Zork all the way through, however, I have made some
changes to the intepreter since then, so I cannot guarantee success. If the
interpreter crashes, let me know. (note that there are bugs in the
game; if you get dumped to a MDL LISTEN prompt, this might not be an
If you modify the MDL sources, you can re-build the game by running
the interpreter with no parameters in the mdlzork directory, and
This will rebuild the MDL/MADADV.SAVE file and start the game.
Confusion probably won't be developed further.
Notable features not supported: proper SAVE/RESTORE (an incompatible but
useful version is provided), GC-DUMP/GC-READ, interrupts, processes,
overflow, compiled code.
Copyright 2009 Matthew T. Russotto
You can redistribute and/or modify this file under the terms of the
GNU General Public License as published by the Free Software
Foundation, either version 3 of the License, or your option) any later
This file is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see .