1.  Introduction

     Computer games have existed for nearly as long as	com-
puters	have existed.  One of the most popular computer	pro-
grams of all time is Adventure.	 In Adventure, the player is
placed inside a	world which exists only	in the memory of the
computer (and the mind of the player).	The player interacts
with this world	by means of English-like sentences.  Objects
that the player	finds may be taken, opened, closed,  tasted,
thrown,	and otherwise manipulated.

     Previously, most programmers attempting to	write  their
own  Adventure-like  game  have	 been  bogged  down  by	such
trivial	details	as implementing	a parser for  player  input,
properly  responding  to  the player's commands, and dealing
with the passage of time.  ADL is intended  to	relieve	 the
programmer  of	such  worries and to allow the programmer to
concentrate on the important details of	the imaginary world.
The  following	is  a  short excerpt from the play of a	game
which was written in ADL:

     Red room.
     You are in	a large	room which is illuminated by a bright red glow.
     Exits lie to the east and south.
     > Go east.
     Green room.
     You are in	a smallish room	which is illuminated by	a pleasant green
     glow.  The	only exit is to	the west.
       There is	a robot	here.
     > west
     Red room.
     > s
     Blue room.
     You are in	a tiny room which is barely illuminated	by a dim blue
     glow.  There is an	exit to	the north, and you seem	to make	out
     something on the floor.  There is a button	on the wall.  Above the
     button is a sign that reads:

		     DANGER!

		  HIGH VOLTAGE!

     > n
     Red room.
     > e
     Green room.
     You can see:
       a robot
     > Tell the	robot "Go west then south.  Push the button then go north."
     "Sure thing, Boss."
     The robot exits to	the west.

     Notice that this script demonstrates powerful  features
not  present in	many other Adventure-like games.  This docu-
ment will describe the utilities and "tricks"  necessary  to
write games such as the	above.