Kinds Index Table of all the kinds;   how arithmetic affects them; and   details of each kind in turn. What are kinds?  ; More about kinds of object  ; And kinds of value

value	default value	repeat	props	under
number	0
time	9:00 AM
object	nothing
room [2]	Street
thing [10]	yourself
door	--
container [1]	ignition
vehicle	--
player's holdall	--
supporter	--
backdrop	--
person [1]	yourself
man	--
woman	--
animal	--
device	--
direction [12]	north
region	--
scene [2]	the Entire Game
truth state [2]	false
text	""
indexed text	""
stored action	waiting
list of any kind	{ }
rule [797]	the little-used do nothing rule
rulebook [377]	the action-processing rules
action-name [84]	waiting action
activity [32]	printing the name
table-name [3]	a table with no rows or columns
equation-name	an equation doing nothing
figure-name [1]	figure of cover
sound-name	a silent non-sound
external-file	a non-file
snippet	word 1 of command
description	matching nothing

The default value is used when we make something like a variable but don't tell Inform what its value is. For instance, if we write 'Zero hour is a time that varies', but don't tell Inform anything specific like 'Zero hour is 11:21 PM.', then Inform uses the value in the table above to decide what it will be. The same applies if we create a property (for instance, 'A person has a number called lucky number.'). Kinds of value not included in the table cannot be used in variables and properties.

A tick for repeat means that it's possible to repeat through values of this kind. For instance, 'repeat with T running through times:' is allowed, but 'repeat with N running through numbers:' is not - there are too many numbers for this to make sense. A tick here also means it's possible to form lists such as 'list of rulebooks', or to count the 'number of scenes'.

A tick for props means that values of this kind can have properties. For instance, 'A scene can be thrilling or dull.' makes an either/or property of a scene, but 'A number can be nice or nasty.' is not allowed because it would cost too much storage space. (Of course 'Definition:' can always be used to make adjectives applying to numbers; it's only properties which have storage worries.)

A tick for under means that it's possible to understand values of this kind. For instance, 'Understand "award [number]" as awarding.' might be allowed, if awarding were an action applying to a number, but 'Understand "run [rule]" as rule-running.' is not allowed - there are so many rules with such long names that Inform doesn't add them to its vocabulary during play.

Kinds of value marked with the calculator symbol are numerical - these are values we can add, multiply and so on. The range of these numbers depends on the Format setting for the project (Glulx format supports much higher numbers than Z-code).

kind of value	minimum	maximum	dimensions
number	1	32767	dimensionless
time	1 minute	23 hours 59 minutes	(time)

time (plural times) 
A time of day, written in the form '2:34 AM' or '12:51 PM', or a length of time such as '10 minutes' or '3 hours 31 minutes', which must be between 0 minutes and 23 hours 59 minutes inclusive.

object (plural objects)
Objects are values intended to simulate physical things: places, people, things, and so on. They come in many kinds. The special value 'nothing' is also allowed, and can be used to mean 'no object at all'.

room (plural rooms) 
Represents geographical locations, both indoor and outdoor, which are not necessarily areas in a building. A player in one room is mostly unable to sense, or interact with, anything in a different room. Rooms are arranged in a map.
Usually lighted not dark, unvisited not visited.
Can have description (some text), printed name (some text), map region (an object).
Street , In your car 

thing (plural things)
Represents anything interactive in the model world that is not a room. People, pieces of scenery, furniture, doors and mislaid umbrellas might all be examples, and so might more surprising things like the sound of birdsong or a shaft of sunlight.
Usually unlit not lit, inedible not edible, portable not fixed in place, singular-named not plural-named, improper-named not proper-named, described not undescribed, unmarked for listing not marked for listing, mentioned not unmentioned.
Usually not scenery, wearable, pushable between rooms, handled.
Can have description (some text), printed name (some text), indefinite article (some text), initial appearance (some text), printed plural name (some text), matching key (an object).
pinstriped navy blue suit , bunch of keys , corporate logo , unassuming tie , seatbelt , steering wheel , car radio , power button 

door, a kind of thing (plural doors) 
Represents a conduit joining two rooms, most often a door or gate but sometimes a plank bridge, a slide or a hatchway. Usually visible and operable from both sides (for instance if you write 'The blue door is east of the Ballroom and west of the Garden.'), but sometimes only one-way (for instance if you write 'East of the Ballroom is the long slide. Through the long slide is the cellar.').
Always fixed in place not portable.
Usually closed not open, openable not unopenable, unlocked not locked.
Usually not lockable.
Never pushable between rooms.
Can have other side (an object).

container, a kind of thing (plural containers)
Represents something into which portable things can be put, such as a teachest or a handbag. Something with a really large immobile interior, such as the Albert Hall, had better be a room instead.
Usually opaque not transparent, open not closed, unopenable not openable, unlocked not locked.
Usually not enterable, lockable.
Can have carrying capacity (a number).
ignition 

vehicle, a kind of container (plural vehicles) 
Represents a container large enough for a person to enter, and which can then move between rooms at the driver's instruction. (If a supporter is needed instead, try the extension Rideable Vehicles by Graham Nelson.)
Always enterable.
Usually fixed in place not portable.

player's holdall, a kind of container (plural player's holdalls) 
Represents a container which the player can carry around as a sort of rucksack, into which spare items are automatically stowed away.
Always portable not fixed in place.
Usually openable not unopenable.

supporter, a kind of thing (plural supporters)
Represents a surface on which things can be placed, such as a table.
Usually fixed in place not portable.
Usually not enterable.
Can have carrying capacity (a number).

backdrop, a kind of thing (plural backdrops) 
Represents an aspect of the landscape or architecture which extends across more than one room: for instance, a stream, the sky or a long carpet.
Always fixed in place not portable.
Usually scenery.
Never pushable between rooms.

person, a kind of thing (plural people) 
Despite the name, not necessarily a human being, but anything animate enough to envisage having a conversation with, or bartering with.
Usually male not female.
Usually not neuter.
Can have carrying capacity (a number).
yourself

man, a kind of person (plural men)
Represents a man or boy.
Always male not female.
Never neuter.

woman, a kind of person (plural women)
Represents a woman or girl.
Always female not male.
Never neuter.

animal, a kind of person (plural animals)
Represents an animal, or at any rate a non-human living creature reasonably large and possible to interact with: a giant Venus fly-trap might qualify, but not a patch of lichen.

device, a kind of thing (plural devices) 
Represents a machine or contrivance of some kind which can be switched on or off.
Usually switched off not switched on.

direction (plural directions) 
Represents a direction of movement, such as northeast or down. They always occur in opposite, matched pairs: northeast and southwest, for instance; down and up.
Usually unmarked for listing not marked for listing.
Can have opposite (direction).
north, northeast, northwest, south, southeast, southwest, east, west, up, down, inside, outside

region (plural regions) 
Represents a broader area than a single room, and allows rules to apply to a whole geographical territory. Each region can contain many rooms, and regions can even be inside each other, though they cannot otherwise overlap. For instance, the room Place d'Italie might be inside the region 13th Arrondissement, which in turn is inside the region Paris. Regions are useful mainly when the world is a large one, and are optional.

scene (plural scenes) 
Like a scene in a play: a period of time which is usually tied to events in the plot. Scenes are created by sentences like 'Midnight Arrival is a scene.'

truth state (plural truth states) 
The state of whether something is 'true' or 'false'. (In other computing languages, this might be called 'boolean', after the 19th-century logician George Boole, who first realised this was a kind of value.)

text (plural texts)
Some text in double quotation marks, perhaps with substitutions written in square brackets.

indexed text (plural indexed texts) 
A flexible-length form of text which can be internally altered and searched. Inform automatically changes text to this format when necessary.

stored action (plural stored actions) 
A stored action, which can later be tried.

list of any kind (plural lists of any kind) 
A flexible-length list of values, where all of the items have to have the same kind of value as each other - for instance, a list of rooms, or a list of lists of numbers. The empty list, with no items yet, is written { }, and a list with items in is written with commas dividing them - say {2, 5, 9}.

rule (plural rules) 
One of many, many rules which determine what happens during play. Rules can be triggered by scenes beginning or ending, by certain actions, at certain times, or in the course of carrying out certain activities.

rulebook (plural rulebooks) 
A list of rules to follow, in sequence, to get something done. A rulebook is like a ring-binder, with the individual rules as sheets of paper. Inform normally sorts these into their 'natural' order, with the most specific rules first, but it's easy to shuffle the pages if you need to. When some task is carried out during play, Inform is normally working through a rulebook, turning the pages one by one.

action-name (plural action-names) 
An action is what happens when one of the people in the simulated world decides to do something. A full action would be something like 'dropping the box', but an action name is just the choice of which sort of thing is being done: here, it's 'the dropping action'. (Action names are always written with the word 'action' at the end, to make sure they aren't mistaken for full actions.)

activity (plural activities) 
An activity is something which Inform does as part of the mechanics of play - for instance, printing the name of an object, which Inform often has to do. An activity can happen by itself ('printing the banner text', for instance) or can be applied to an object ('printing the name of something', say).

table-name (plural table-names) 
Like tables of information in a book or newspaper, tables in Inform hold values which have been organised into rows and columns. A table-name is just a single value, identifying which table is meant - say, 'Table of US Presidents' might be a table-name value.

equation-name (plural equation-names)
Like formulae in a textbook or a scientific paper, equations in Inform are written out in displayed form and given names.

figure-name (plural figure-names) 
When made with the Glulx setting, an Inform project can include images as well as words, and these are called figures. A figure-name is just the name of one of the figures in the current project.

sound-name (plural sound-names) 
When made with the Glulx setting, an Inform project can include sound effects or pieces of music. A sound-name is just the name of one of these sounds in the current project.

external-file (plural external-files) 
When made with the Glulx setting, an Inform project can make limited use of files stored on the computer which is operating the story at run-time. An external-file is just the name of one of these files (not the filename in the usual sense, but a name given to it in the Inform source text).

snippet (plural snippets) 
A fragment of the player's most recent typed command, taking in a run of consecutive words.

description (plural descriptions) 
A description of objects - say, 'animals which are in closed containers' - may not look like a value, but it is. Writing 'the number of visible women', for instance, actually applies the phrase 'number of...' to the value 'visible women', this being a description. (We very rarely need to know this, but occasionally it's useful to store descriptions or do other value-related things with them.)