I had also written a document called "Tricky Document" which describes several tricks involved with Z-machine programming (many of which Infocom did not use). http://zzo38computer.org/zmachine/doc/tricky.txt (I also wrote implementations of Z-machine in C, PostScript, JavaScript, and Glulx.)
Another text adventure system that I know of is "OASYS". The VM code was not documented, although it did include source code, and I have figured it out from the source code and written a document. The included OAC compiler was rather limited (no include files, you could not call a function that is defined later in the file, ambiguous syntax, strings duplicated in the output file, no pointer types, no type checking, no macros, no arrays, no bitwise operations, spurious vocabulary entries, and various other limitations), so I had written my own compiler (which still uses the same VM code, but with an entirely different syntax).
I had also written a document called "Tricky Document" which describes several tricks involved with Z-machine programming (many of which Infocom did not use). http://zzo38computer.org/zmachine/doc/tricky.txt (I also wrote implementations of Z-machine in C, PostScript, JavaScript, and Glulx.)
Another text adventure system that I know of is "OASYS". The VM code was not documented, although it did include source code, and I have figured it out from the source code and written a document. The included OAC compiler was rather limited (no include files, you could not call a function that is defined later in the file, ambiguous syntax, strings duplicated in the output file, no pointer types, no type checking, no macros, no arrays, no bitwise operations, spurious vocabulary entries, and various other limitations), so I had written my own compiler (which still uses the same VM code, but with an entirely different syntax).