House 3 Inform Tutorial
From IFWiki
In 1998, David Cornelson put together a set of Inform 6 source files that would help beginners with their interactive fiction education. They are recreated here.
Jump to any of the source code examples: Tutorial 1 | Tutorial 2 | Tutorial 3 | Tutorial 4 | Tutorial 5 | Tutorial 6 | Tutorial 7 | Tutorial 8
Return to main article: House Tutorial (Inform)
! ------------------------------------------------------------------------------
! Inform for New Writers
!
! The House - Version 3
!
! Last Modified: David Cornelson - 22-Jan-1998
!
! This work is freely offered to the Public Domain. - DAC 12-12-2015
!
! ------------------------------------------------------------------------------
Constant DEBUG;
Constant Story "The House";
Constant Headline
"^Inform for New Writers^
The House - Version 3^
By New Writer (1998) - Last Compiled: 22-Jan-1998^";
Constant MAX_SCORE 100;
Serial "980122";
Release 2;
Include "Parser";
Include "VerbLib";
!-------------------------------------------------------------------------------
! Initialise
!
!-------------------------------------------------------------------------------
[ Initialise;
location = Sidewalk;
];
[ PrintRank;
print ", earning you the rank of ";
if (score >= 100) "the greatest.";
if (score >= 80) "above average.";
if (score >= 60) "average.";
if (score >= 40) "below average.";
if (score >= 20) "the barely living.";
"the living dead.";
];
! ----------------------------------------------------------------------------
! Locations
!
! In this section we will define our locations. These are "Objects" to Inform.
!
! ----------------------------------------------------------------------------
Object Sidewalk "Sidewalk"
with description
"You are standing on the sidewalk in front of a house to the west.",
w_to Front_Porch,
has light;
!
! Notice we changed the w_to and in_to properties to reflect our new door.
! We changed the description to reflect our new doors as well...
!
Object Front_Porch "Front Porch"
with description
"This is the front porch of the house. There are two doors
leading inside. The door on the left leads west and the
door on the right leads northwest.",
e_to Sidewalk,
w_to Left_Front_Door,
in_to Left_Front_Door,
nw_to Right_Front_Door,
has light;
!
! VERSION 3 - Adding a door
!
! Inform allows you to create special objects that represent doors. Doors
! are simply objects with special "properties" and "attributes".
!
! A "property" is a function that can be listed in the "Object" statement.
! For instance, "e_to" and "w_to" are properties.
!
! Properties that are used for doors are:
!
! - door_to Tells Inform where the door leads if 'entered'.
!
! - door_dir Tells Inform which direction the door faces.
!
! - when_open The description of the door when open.
!
! - when_closed The description of the door when closed.
!
! - found_in A list of locations where the door resides.
!
! - with_key Specify which object is needed to lock and unlock door.
!
! Attributes that are used for doors:
!
! - static OR Tells Inform that the door cannot be carried.
! - scenery Tells Inform that the door cannot be carried
! and also is not mentioned in normal location
! descriptions.
!
! - door Mandatory...tells Inform this object is a door.
!
! - open Current state of door. To make the door start
! 'closed', then give the object the attribute
! ~open.
!
! - lockable Can be locked.
!
! - locked Starts out locked. Give it ~locked to start
! it as unlocked.
!
! NOTE: A few of the properties and attributes above can be used with other
! objects. The only ones specific to a door object are the 'door_to'
! and 'door_dir' properties and the 'door' attribute.
!
! NOTE ABOUT THE TILDE CHARACTER:
! In evaluations of variables, the tilde character, ~, signifies
! 'not' or 'false value of'.
! When you see ~=, this means "not equal to".
! When you see ~attribute, this means "the false value of attribute".
!
! The tilde character, ~, has another use. Inside a string, if you
! want to print a double-quote, you would use the tilde. For example:
!
! print "John said, ~Run spot run!~";
!
! ...would print...
!
! John said, "Run spot run!"
!
!
! We have two front doors built into our house, one leading to the
! foyer, and the other leading to the den.
!
! The left door is a one way door that has no lock. You can enter
! the door to the west.
!
! The right door is a two-way door that is lockable. The key is
! located in the north bedroom. You enter the door to the northwest.
!
! Q: What is the '->' used for?
!
! A: This symbol tells Inform that this object is located 'within' the most recent
! location definition.
!
! If two arrows are used, then the object is within the most recent -> object.
!
! The 'Left_Front_Door' is a 'child' of the 'Front_Porch' and the
! 'Front_Porch' is the 'parent' of 'Left_Front_Door'.
Object -> Left_Front_Door "left front door"
with name "left" "front" "door",
description
"The left front door is made of brass.",
when_open "The left front door is open.",
when_closed "The left front door is closed.",
door_to Foyer,
door_dir w_to,
has static door openable;
!
! The two-way door has 'functions' for the door_to and door_dir properties
! because you can start on the front porch or the den. The same is true for
! the directions, you can either be going through the door northwest or
! southeast.
!
! These are 'embedded functions'. They don't need a name or arguments so
! you place a semi-colon immediately after the first bracket. The end of
! the function is signified by the closing bracket. You separate embedded
! functions the same way you separate other properties, with a comma.
!
! The 'if' statement within both of the embedded functions is used to
! determine which location you are starting in for the two-way door.
!
! The determination is calculated by comparing the 'location' variable
! (which Inform ALWAYS sets to the players current location) and the
! Front_Porch. If this is true, the first statement (until the semi-colon)
! is executed. If it's false (the player is NOT in the Front_Porch) then
! the second statement is executed.
!
! Notice the 'found_in' property lists both the Front_Porch and Den. This
! is so you can 'see' the doors in both of these locations.
!
Object Right_Front_Door "right front door"
with name "right" "front" "door",
description
"The right front door is made of wood.",
when_open "The right front door is open.",
when_closed "The right front door is closed.",
door_to [; if (location==Front_Porch) return Den; return Front_Porch; ],
door_dir [; if (location==Front_Porch) return nw_to; return se_to; ],
found_in Front_Porch Den,
with_key right_key,
has static door openable lockable locked;
Object Den "Den"
with description
"You are in the den of the house.",
se_to Right_Front_Door,
out_to Right_Front_Door,
has light;
Object Foyer "Foyer"
with description
"You are standing in the foyer of the house. It seems as though
you can go up a staircase, northwest, or back out the front
door to the east.",
out_to Front_Porch,
e_to Front_Porch,
nw_to Hallway,
u_to Upper_Hallway,
has light;
Object Hallway "Hallway"
with description
"You are in the hallway on the first floor of the house. The
foyer is southeast and the kitchen is west of here.",
se_to Foyer,
w_to Kitchen,
has light;
Object Kitchen "Kitchen"
with description
"This is the kitchen of the house. A hallway can be seen to the
east.",
e_to Hallway,
has light;
Object Upper_Hallway "Upper Hallway"
with description
"This is the second floor hallway. Rooms can be seen north and
south and a staircase leads down.",
n_to North_Bedroom,
s_to South_Bedroom,
d_to Foyer,
has light;
Object North_Bedroom "North Bedroom"
with description
"This is a bedroom on the north side of the house.",
s_to Upper_Hallway,
has light;
!
! This is the 'key' for the right front door. There are no directions
! or attributes since it's a just a simple object.
!
! I placed the key here to keep these examples building a workable game.
! You can move the key anywhere you like though by cutting this line and
! pasting it 'below' any other location object.
!
! Remember, this is the object listed in 'with_key' in the right_door
! object, so it's the only way to unlock that door.
!
Object -> right_key "right key" with name "right" "key";
Object South_Bedroom "South Bedroom"
with description
"This is a bedroom on the south side of the house.",
n_to Upper_Hallway,
has light;
! ----------------------------------------------------------------------------
! Grammar
!
! The grammar section includes the file "Grammar" and will later include
! extensions to the standard grammar library.
!
! ----------------------------------------------------------------------------
Include "Grammar";
! Compilation results: INFRMW32 -J HOUSE03.INF
!
!PC/Win32 Inform 6.14 (8th September 1997)
! 6 "compass"
! 7 "north wall"
! 8 "south wall"
! 9 "east wall"
! 10 "west wall"
! 11 "northeast wall"
! 12 "northwest wall"
! 13 "southeast wall"
! 14 "southwest wall"
! 15 "ceiling"
! 16 "floor"
! 17 "outside"
! 18 "inside"
! 19 "(darkness object)"
! 20 "(self object)"
! 21 "(Inform Parser)"
! 22 "(Inform Library)"
! 23 "(with no short name)"
! 24 "Sidewalk"
! 25 "Front Porch"
! 26 "left front door"
! 27 "right front door"
! 28 "Den"
! 29 "Foyer"
! 30 "Hallway"
! 31 "Kitchen"
! 32 "Upper Hallway"
! 33 "North Bedroom"
! 34 "right key"
! 35 "South Bedroom"