# '#' means this line (or the rest of this line) is a comment
# (if you want to output '#' during your game, use "#")
game Cloak of Darkness # Game title
id CLOD # game ID (used to identify cookies; should be unique on your site)
author Roger Firth, adapted to Gruescript by Robin Johnson
version 0.0.1
person 2 # 2nd person, i.e. "You are in..."
examine off # if 'on', the verb 'examine' will be implemented by clicking nouns
status { $Room } | { $cloaked } # '|' divides left and right ends of status bar

# a portable item
thing cloak pitch-black opera cloak
carried # starts in inventory
tags portable wearable worn # all special engine-recognised tags

# setting "cloaked" will set the status bar
var cloaked Cloaked
rule
assign cloaked Cloaked
!has cloak worn
assign cloaked Uncloaked

# a room
room foyer You're in the foyer of the Opera House. # internal name and description
tags start # the player starts here
south bar # directions to other rooms
west cloakroom
north foyer

# block an exit
verb go north 
at foyer
say But you've only just arrived!

room bar You're in the bar.
north foyer

# set the state of the bar BEFORE entering it
verb go south
at foyer
run check_bar
continue # fails, so default movement behaviour will always happen

proc check_bar
carried cloak
tag bar dark # 'dark' is a special tag

proc check_bar
thingat cloak bar
tag bar dark

# both 'carried cloak' and 'thingat cloak bar' must have failed
proc check_bar
untag bar dark

rule
at bar
has bar dark
add mess 1
!eq $mess 2: You should probably go back out to the foyer – you wouldn't want to accidentally disturb anything in the dark. # message printed if assertion fails

room cloakroom You're in a small cloakroom.
east foyer

# non-portable item
thing hook brass hook
loc cloakroom # the room it starts in

# setverb blocks determine when to activate verbs for things
setverb hang hook # when to activate 'hang' verb for the hook
has $held wearable
# note: we're placing the 'hang' verb on the hook, rather than the cloak.
# in a parser game you would type "hang cloak" (or "hang cloak on hook")
# so we might have put the verb on the cloak instead. But it's more intuitive
# to see the verb button next to the hook: you hold the cloak, then look round
# the room, a bit like a graphical point-n-click. we'll change 'display' and
# 'prompt' for the verb, so that the player sees "hang cloak"

verb hang
display hang {$held} # how it's displayed in the button
prompt hang {$held} on {$this} # how it's displayed at the mock command prompt
tag $held hooked # add an (author-defined) tag
say You hang {the $held} on {the $this}.
put $held $this.loc # 'held' and 'this' are special contextual variables

tagdesc hooked on hook # will be displayed with the object

# taking anything that is 'hooked' removes that tag
verb take
has $this hooked # if an assertion 'fails', control will move to the native verb 'take'
untag $this hooked
continue # always 'fails', 'take' will pick up the action

thing dust dust (on the floor)
tags mass_noun # i.e. 'some dust', not 'a dust'
loc bar

rule
at bar
!has bar dark
lt $mess 3 # if the value of the variable 'mess' is less than 3
say A message is scrawled in the dust! It reads:
die You win # end the game

rule
at bar
!has bar dark # rules are processed in order of declaration
say A message is scrawled in the dust!
say What a pity, it's too scuffed to read.
die You lose