Program 4	Dordal		Due: December 6, 2002

You are to modify the game program presented in class, adding the
following features:

1. Add a second lantern or other Lightable. Try to do this in such a way 
that you don't need to keep these Lightable objects as global variables,
although that is an acceptable way to do it.


2. If you eat the chocolate, it should go away.

Optional: the chocolate should last 2-3 bites. Keep the number of bites left
as an attribute of the chocolate itself. 


3. Introduce a puzzle room where you cannot *leave* the room until some
action occurs. Possibilities are:
    You have to FIGHT the dragon (with a SWORD?)
    You have to GIVE the dragon a PRESENT or COOKIE.
    There is a cave-in and you have to DIG (with SHOVEL?)


4. You are to add one additional puzzle of your own. Your puzzle should,
at a minimum, involve the following:
	one new CarryObj 
	one new verb 
	one new derived room class, with special behavior for 
		at least one verb (new or existing).
	some kind of state change to the room or to an object
	 	(like the stone being moved or valve being turned)

Here are a few possibilities.

UNLOCK CHEST with a KEY found elsewhere; once the chest is unlocked,
something should be inside.

Cross a rickety two-move bridge over a bottomless pit; if you carry too
much the bridge will break; you can only carry two things at a time.

Have goblins attack you in a pitch-black cave room, if you fail to
LIGHT LANTERN within 2 turns. Note that this puzzle involves keeping
count of turns.

You need to CAST SPELL in the WizardsChamber, but in order to do this
you must first find in the game a BELL, BOOK, and CANDLE. (And maybe
LIGHT CANDLE? Or maybe, in the simpler direction, just find NEWTEYE 
and BATWING. If you try to CAST SPELL and don't have the ingredients,
the game should tell you what you're missing.)


Be sure all verbs you introduce are handled at some primitive level
by default_interpret(), so that they're not completely unrecognized
even if you're not in the "right" room.