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5 During our travels, we've encountered certain terms which have particular
6 significance in the context of the Inform text adventure development
7 system; here are brief definitions of many of those specialised words and
13 The generated effect of the player's input, usually by the
14 :term:`parser` but also occasionally by the designer's code. It
15 refers to a single task to be processed by Inform, such as DROP
16 KETTLE, and it's stored in four numbers: one each for the action
17 itself and the ``actor`` object who is to perform it (the player or
18 an :term:`NPC`), one for the ``noun`` -- or direct object, if
19 present -- and a fourth for the ``second`` noun -- if it exists, for
20 example the "POT" in THROW KETTLE AT POT. See also :term:`fake
24 The testing which is carried out by the game's :term:`designer`, in
25 a futile attempt to ensure that it does everything that it should
26 and nothing that it shouldn't. See also :term:`beta-testing`.
29 A parameter supplied in a call to a :term:`routine`, which is the
30 actual value for one of the routine's defined local variables. For
31 example, the argument is 8 in the call ``MyRoutine(8)``. The
32 definition of the routine includes the variable that will hold the
33 argument, in this case ``x``: ``[ MyRoutine x; ... ];``
36 See :term:`text file`.
39 A statement which sets or changes the value of a :term:`variable`.
40 There are three in Inform: ``=`` (set equal to), ``++`` (add one to
41 the current value), ``--`` (subtract one from the current value).
44 Named flags that can be defined for an object after the keyword
45 ``has`` . An attribute is either present (on) or not present
46 (off). The designer may test from any other part of the program
47 *if* an object *has* a certain attribute, *give* an attribute to an
48 object or take it away as need arises. For instance, the attribute
49 ``container`` states that the object is capable of having other
50 objects placed inside it.
57 Information about a game which is displayed at the start of play.
60 The testing which is carried out by a small band of trusted
61 volunteers, prior to general public release, during which the gross
62 inadequacy of the designer's :term:`alpha-testing` effort becomes
67 A computer file containing binary data -- 0s and 1s -- which is
68 created by a program and which only a program can understand.
71 Used to highlight a term explained in this glossary.
74 See :term:`object tree`.
77 A special :term:`object` template from which other objects can
78 inherit :term:`properties` and/or :term:`attributes`. The template
79 must begin with the word ``Class`` and must have an internal
80 identifier. Objects that wish to inherit from a class usually
81 begin with the internal ID of the class in place of the word
82 ``Object`` , but may instead define a segment ``class`` followed by
83 the class's internal ID. The designer may test whether an object
84 belongs to -- is a member of -- a class.
87 See :term:`statement block`.
90 Text which starts with an exclamation mark ``!`` and which is
91 ignored by the compiler when it reads the :term:`source file`;
92 added to improve the file's layout or for explanatory notes.
95 The time when the :term:`compiler` is at work making the
96 :term:`story file`. See also :term:`run-time`.
99 A program that reads the source code written by the designer and
100 turns it into a :term:`story file`, which can then be played by a
101 Z-machine :term:`interpreter`.
104 A particular value which is defined at :term:`compile-time`, always
105 stays the same and cannot be changed while the game is being
106 played. Common examples include numbers, strings and the internal
107 IDs of objects, any of which can be either written out explicitly
108 or set as the value of a named ``Constant``.
111 A option which causes to compiler to include extra code into the
112 story file, thus making it easier for the designer to understand
113 what's happening while a game is being tested prior to release.
114 See also :term:`Strict mode`.
117 A person who uses Inform to create a text adventure game: in other
118 words, gentle reader, you.
121 The collection of all input words "understood" by the game.
124 A word written in single quotes '...' within the :term:`source
125 file`, usually (but not exclusively) as one of the values assigned
126 to an object's ``name`` property. All such words are stored in the
127 :term:`dictionary`, which is consulted by the :term:`parser` when
128 attempting to make sense of a player's command. Only the first
129 nine characters are significant (thus ``'cardiogram'`` and
130 ``'cardiograph'`` are treated as the same word). Use
131 ``'coins//p'`` to mark "``coins``" as plural, referring to all coin
132 objects which are present. Use ``'t//'`` to enter the
133 single-character word "t" into the dictionary (``'t'`` is a
134 constant representing a character value).
137 A line of Inform code which asks the :term:`compiler` to do
138 something there and then, at :term:`compile-time`; typical examples
139 are to Include the contents of another file, or to set aside some
140 space within the story file where a variable value may be stored.
141 Not to be confused with a :term:`statement`, which asks the
142 compiler to compose an instruction which the interpreter will obey
143 at :term:`run-time`; typical examples are to display some text, or
144 to change the value held within a variable's storage space.
147 A general-purpose program for creating and modifying :term:`text
151 A routine that is defined in the body of an object, as the value of
152 one of its :term:`properties`. Unlike a :term:`standalone
153 routine`, an embedded routine doesn't have a name of its own, and
154 returns ``false`` if execution reaches the terminating marker
158 One of a predefined list of optional routines which, if you provide
159 it, will be called by the library either to produce some
160 supplementary output or to return a value causing the library to
161 change its default behaviour.
164 An action generated indirectly by the library rather than directly
165 by what the player types. For example, PUT X IN Y triggers a real
166 action of Insert (which can be intercepted by X) and a fake action
167 of Receive (which can be intercepted by Y).
170 A logical state which is the opposite of :term:`true`, represented
174 A variable which can take only two possible values.
180 A variable not specific to any routine or object, which can be used
181 by any routine in the game.
184 The process by which an :term:`object` belonging to a :term:`class`
185 acquires the properties and attributes of said class. Inheritance
186 happens automatically; the designer has just to create class
187 definitions, followed by objects having those classes.
190 A program that reads the :term:`story file` of a game and enables
191 people to play it. Interpreters must be platform-specific (that
192 is, they will be different programs for each operating system),
193 thus allowing the story file to be universal and
194 platform-independent.
197 Used for emphasis, and as a placeholder to represent a value which
201 A group of text files, part of the Inform system, that includes the
202 :term:`parser`, definitions for the :term:`model world`, language
203 files, grammar definitions and a customised stock of default
204 answers and behaviour for the player's actions. The library will
205 make frequent calls to the game file to see if the designer wants
206 to override those defaults.
209 The actual files containing the source code of the library. There
210 are basically three (although these three Include other files as
211 well): ``parser.h`` , ``verblib.h`` and ``grammar.h``, and they
212 should be Included in every Inform game.
215 One of a set of routines included as part of the library which the
216 designer can call to perform some commonly useful task.
219 A variable which is part of only one :term:`routine`; its value
220 remains unavailable to other routines in the game. The value of a
221 local variable is *not* preserved between calls to the routine.
224 The imaginary environment which the player character inhabits.
227 The ASCII control character(s) used to mark the end of a line of
231 A non-player character; any character other than the protagonist.
232 Could range from an opponent or love interest to a pet gerbil or a
236 A group of :term:`routine`\s and variables bundled up together in a
237 coherent unit. Objects represent the items that make up the
238 :term:`model world` (a torch; a car; a beam of light; etc.), a fact
239 which organises the designer's code in sensible chunks, easy to
240 manage. Each object has two parts: the header, which comprises the
241 internal ID, the external name and its defined parent (all fields
242 are optional), and the body, which comprises the property variables
243 and attribute flags particular to that object, if any.
246 A hierarchy that defines objects' relationships in terms of
247 containment. Each :term:`object` is either contained within
248 another object -- its parent -- or is *not* contained; objects such
249 as rooms which are not within another object have the constant
250 ``nothing`` (0) as a parent. An object contained within another is
251 a child. For example, a shoe inside a box: the box is the shoe's
252 parent and the shoe is a child of the box. Consider now this box
253 being inside the wardrobe. The box is a child of the wardrobe, but
254 the shoe is still a child of the box, not the wardrobe. In a
255 normal game, the object tree will undergo many transformations as
256 the result of the player's activities.
259 See :term:`object tree`.
262 Part of the :term:`library` which is responsible for analysing the
263 player's input and trying to make sense of it, dividing it into
264 separate words (verb, nouns) and trying to match them against the
265 words stored in the game's :term:`dictionary` and the actions
266 defined in the game's grammar. If the player's input makes sense,
267 the parser will trigger the resulting :term:`action`; if not, it
268 will complain that it didn't understand.
271 1. a personal computer;
272 2. the player character (see :term:`player`).
275 1. the final user of the game, normally a person full of radical
276 opinions about your capabilities as a designer;
277 2. a variable referring to the :term:`object` -- sometimes known as
278 an "avatar" -- which currently represents that user within the
282 A customised rule to apply while in a ``print`` or ``print_ret``
283 statement, to control the manner in which an item of data is to be
284 displayed. For example: ``print (The) noun, " is mine."`` is
285 telling the game to use a capitalised definite article for the
286 noun. The library defines a stock of print rules, and designers
287 may create some of their own.
290 Variables attached to a single :term:`object`, of which they are a
291 part. They are defined in the body of the object after the keyword
292 ``with`` and have a name and a value. The latter (which defaults
293 to 0) can be a number, a string "...", a dictionary word '...' or
294 an embedded routine ``[;...]``; it can also be a list of those
295 separated by spaces. The value of an object's property can be
296 tested and changed from any part of the game. The fact that an
297 object provides a property may be tested.
300 The ``rec.arts.int-fiction`` Usenet newsgroup for IF designers.
304 The ``rec.games.int-fiction`` Usenet newsgroup for IF players.
307 An :term:`object` which defines a geographical unit into which the
308 map of the :term:`model world` is divided. Rooms have no parent
309 object (or, more precisely, their parent object is ``nothing``) and
310 they represent the places where the player character is at any
311 given moment -- the player character can't be in more than one room
312 at a time. Note that the name "room" does not imply necessarily
313 "indoors". A clearing, a sandy beach, the top of a tree, even
314 floating in outer space -- these are all possible room objects.
317 In general terms, a routine is a computer program that makes some
318 specific calculation, following an ordered set of instructions;
319 this is the only unit of coherent and executable code understood by
320 Inform. More practically, a routine is a collection of
321 :term:`statement`\s which are written between markers ``[...]``.
322 When a routine is "called", possibly with arguments -- specific
323 values for its defined variables, if they exist -- the interpreter
324 executes the statements in sequence. If the interpreter encounters
325 a ``return`` statement, or reaches the ``]`` at the end of the
326 routine, it immediately stops executing statements in the routine
327 and resumes execution at the statement which called that routine.
328 Every routine returns a value, which is either supplied by the
329 return statement or implied by the ] at the end of the routine.
330 See :term:`embedded routine` and :term:`standalone routine`.
333 The period of time when the :term:`interpreter` is running a
334 :term:`story file` (that is, someone is playing the game). See
335 also :term:`compile-time`.
338 A text file containing your game defined using the Inform language.
341 A routine which is not part of an object. Unlike an
342 :term:`embedded routine`, it must provide a name of its own, and it
343 returns ``true`` when execution reaches the terminating marker
347 A single instruction to be executed at :term:`run-time`. See also
351 A group of :term:`statement`\s bundled up together between braces
352 ``{...}``, which are then treated as a single unit -- as if they
353 were only one statement. They commonly appear in loops and
357 A binary file which is the output of the :term:`compiler` and can
358 be played through the use of an :term:`interpreter` (also known as
359 Z-code file or game file). The format of story files is standard
360 and platform-independent.
363 An option which causes the :term:`compiler` to include extra code
364 into the story file, thus making it easier to detect certain design
365 mistakes while a game is being played.
368 A piece of text between double quotes "...", to be displayed for
369 the player's benefit at :term:`run-time`.
372 1. an optional keyword or symbol to operate special features of the
374 2. a statement which decides among different paths of execution
375 according to the value of an expression.
378 A computer file containing words and phrases which a human can
382 A logical state which is the opposite of :term:`false`, represented
383 by any value other than zero (typically 1).
386 A named value which can change during :term:`run-time`. It must be
387 declared before use, either as a ``Global`` variable (available to
388 any routine within the game), or as a local variable (part of one
389 specific routine and usable by that routine alone). Variables have
390 a name and a value; it's the value which is capable of change, not
391 the name. Object :term:`properties` behave as variables.
394 See :term:`story file`.
397 A virtual machine (an imaginary computer simulated by the
398 :term:`interpreter`) on which story files run. Z stands for
399 "Zork", the first ever Infocom title.