[Rails-devel] Saving and logging.

[Iain A. <ia...@co...>]

I've been thinking about the game-save and game requirements, and it seems
to me
that these are best served by a single solution: All the user's funtional
input,
e.g. "Fred buys a B&O share", "PRR lays a #9 on H14/ew" should be saved in a
replayable log. This log could be held in memory until the user decides to
save
the game. This log could then be passed to the next player in a PBEM game,
or just
used to reload a saved state after closing the program.

Advantages are:

 - PBEM and local user game saves solved by the same code.
 - No need to overload implementation code with state save/load code.
 - Easy debugging: "I did the following (log attached), and the program did
the wrong thing."
 - Easy testing: Once you've debugged the previous case, you can replay the
game, and see
   that the code works properly. Whole test suites and regression tests can
be built from this.
 - If everyone in a PBEM game mails the log after their turn to everyone
else, cheating becomes
   impossible, since if you alter the log, any other player can diff your
version against their
   last one, and see what change you've made.

I would, of course, strongly favour using an XML format for saving this
data.

Iain.