The principal maintainers of this code are Eric S. Raymond and Jason
Ninneman. Eric received Don Woods's encouragement to update and ship
-the game; Jason signed on early in the process to help.
+the game; Jason signed on early in the process to help. The assistance
+of Peje Nilsson in restructuring some particularly grotty gotos is
+gratefully acknowledged. Petr Voropaev contributed fuzz testing. Aaron
+Traas did a lot of painstaking work to improve test coverage.
== Nomenclature ==
== Philosophy ==
Extreme care has been taken not to make changes that would alter the
-logic of the game as we received it from Don Woods. By policy, all
-user-visible changes must be revertible with the -o (oldstyle) option.
+logic of the game as we received it from Don Woods, except to fix
+glitches that were clearly bugs. By policy, all user-visible
+changes must be revertible with the -o (oldstyle) option.
-It is a goal of this project to exactly preserve the *behavior* of
-430-point Adventure, but the implementation of it is fair game for
-improvement. In particular, we are concerned to move it to a form that
-is (a) readable, and (b) friendly to forward translation to future
-languages. It has already survived a move from FORTRAN to C; a future
-as a Python or Go translation seems possible, even probable.
+It is a goal of this project to exactly preserve the *intended
+behavior* of 430-point Adventure, but the implementation of it is fair
+game for improvement. In particular, we are concerned to move it to a
+form that is (a) readable, and (b) friendly to forward translation to
+future languages. It has already survived a move from FORTRAN to C; a
+future as a Python or Go translation seems possible, even probable.
== Functional changes ==
+Bug fixes:
+
+* Reading the relocated Witt's End sign in the endgame didn't work right.
+
+* Behavior when saying the giant's magic words outside his room wasn't
+ quite corrected - the game responded as though the player were in
+ the room.
+
+* Attempting to extinguish an unlit urn caused it to lose its oil.
+
By default, advent issues "> " as a command prompt. This feature
became common in many variants after the original 350-point version,
but was never backported into Crowther & Woods's main line before now.
-The "-o" (oldstyle) version reverts the behavior.
+The "-o" (oldstyle) option reverts the behavior.
+
+There is a set of standard one-letter command aliases conventional in modern
+text adventure games; 'l' and 'x'; for 'look' (or 'examine'), 'z' to do nothing
+for a turn, 'i' for 'inventory', 'g' for 'get', and 'd' for 'drop'. The 'd'
+alias collides with 'd' for 'down', but the others have been implemented.
+The "-o" (oldstyle) option disables them.
A "seed" command has been added. This is not intended for human use
but as a way for game logs to set the PRNG (pseudorandom-number generator) so
suite for the game. Any log captured with -l (and thus containing
a "seed" command) will replay reliably, including random events.
-The adventure.text file is no longer required at runtime. Instead, it
-is compiled at build time to a source module containing C structures,
-which is then linked to the advent binary.
+The adventure.text file is no longer required at runtime. Instead, an
+adventure.yaml file is compiled at build time to a source module
+containing C structures, which is then linked to the advent
+binary. The YAML is drastically easier to read and edit than
+the old ad-hoc format of adventure.txt.
-The game-save format has changed. This was done to simplify
-FORTRAN-derived code that formerly implemented these functions;
-without C's fread(3)/fwrite() and structs it was necessarily pretty
-ugly by modern standards. Encryption and checksumming have been
-discarded - it's pointless to try tamper-proofing saves when everyone
-has the source code.
+The game-save format has changed. This was done to simplify the
+FORTRAN-derived code that formerly implemented the save/restore
+functions; without C's fread(3)/fwrite() and structs it was
+necessarily pretty ugly by modern standards. Encryption and
+checksumming have been discarded - it's pointless to try
+tamper-proofing saves when everyone has the source code.
+
+A -r command-line been added. When it is given (with a file path
+argument) it is functionally equivalent to a RESTORE command.
== Translation ==
Jason Ninneman and I have moved it to what is almost, but not quite,
idiomatic modern C. We refactored the right way, checking correctness
-against a comprehesive test suite that we built first and verified with
-coverage tools. This is what you are running when you do "make check".
+against a comprehensive test suite that we built first and verified
+with coverage tools (we have over 95% coverage, with the remaining
+confined to exception cases that are very difficult to reach). This is
+what you are running when you do "make check".
-This move entailed some structural changes. The most important was
-the refactoring of 354 gotos into if/loop/break structures. We
-also abolished almost all shared globals; the main one left is a
-struct holding the game's saveable/restorable state.
+The move to modern C entailed some structural changes. The most
+important was the refactoring of over 350 gotos into if/loop/break
+structures. We also abolished almost all shared globals; the main one
+left is a struct holding the game's saveable/restorable state.
The original code was greatly complicated by a kind of bit-packing
that was performed because the FORTRAN it was written in had no string
verb was one of these words, and what would be string operations in a
more recent language were all done on sequences of these words.
-We are still in the process of removing all this bit-packing cruft
-in favor of proper C strings. C strings may be a weak and leaky
-abstraction, but this is one of the rare cases in which they are
-an obvious improvement over what they're displacing...
+We have removed all this bit-packing cruft in favor of proper C
+strings. C strings may be a weak and leaky abstraction, but this is
+one of the rare cases in which they are an obvious improvement over
+what they're displacing...
+
+We have also conducted extensive fuzz testing on the game using
+afl (American Fuzzy Lop). We've found and fixed some crashers in
+our new code (which occasionally uses malloc(3)), but none as yet
+in Don's old code (which didn't).
-The code falls a short of being fully modern C in the following
+The code falls short of being fully modern C in the following
ways:
* We have not attempted to translate the old code to pointer-based
and the choice to refrain will make forward translation into future
languages easier.
-* There are 20 gotos left that resist restructuring; all but one of
- these are in the principal command interpreter function implementing
- its state machine. A 21st, a two-level loop breakout, is not reducible
- even in principle.
+* There are a few gotos left that resist restructuring; all are in the
+ principal command interpreter function implementing its state
+ machine.
* Linked lists (for objects at a location) are implemented using an array
of link indices. This is a surviving FORTRANism that is quite unlike
to fix it because doing so would (a) be quite difficult, and (b)
compromise forward-portability to other languages.
-* The code still has an unfortunately high density of magic numbers - in
- particular, numeric object and room IDs.
+* Much of the code still assumes one-origin array indexing. Thus,
+ arrays are a cell larger than they strictly need to be and cell 0 is
+ unused.
+
+* The code is still mostly typeless, slinging around machine longs
+ like a FORTRAN or BCPL program. Some (incomplete) effort has been made
+ to introduce semantic types.
+
+We have made exactly one minor architectural change. In addition to the
+old code's per-object state-description messages, we now have a per-object
+message series for state *changes*. This makes it possible to pull a fair
+amount of text out of the arbitrary-messages list and associate those
+mesages with the objects that conceptually own them.
// end
projects / open-adventure.git / blobdiff