7 | |CENTER| *C was a captain, all covered with lace;*
8 | |CENTER| *D was a drunkard, and had a red face.*
12 .. image:: /images/picC.png
15 |C|\onventional -- static -- fiction can be written using nothing more than
16 pencil and paper, or typewriter, or word-processor; however, the
17 requirements for producing IF are a little more extensive, and the creative
18 process slightly more complex.
20 * For static fiction, you first write the text, and then you check it by
21 reading what you've written.
23 * For IF, you still have to write all of the text, but you also have to
24 establish what text gets displayed when. Once you have written the
25 necessary Inform instructions, you use a :term:`compiler` program to
26 convert them into a playable format. The resulting information is played
27 by an :term:`interpreter` program, which permits you to interact with
28 your developing world.
30 With static fiction What You Write Is What You Read, but with IF the format
31 in which you initially write the game doesn't bear much resemblance to the
32 text which the interpreter ultimately displays. For example, the "William
33 Tell" game, in the form that we wrote it, starts like this:
35 .. code-block:: inform
37 !============================================================================
38 Constant Story "William Tell";
40 "^A simple Inform example
41 ^by Roger Firth and Sonja Kesserich.^";
46 !============================================================================
54 You will never need to look at it in the form produced by the compiler::
56 050000012C6C2C2D1EF6010A0C4416900010303230313031004253FEA90C0000
57 0000000000000000000000000000168F000000000000010200000000362E3231
60 but, as you'll notice from the full transcript in :doc:`/appendices/c`, the
61 player will see the following::
63 The place: Altdorf, in the Swiss canton of Uri. The year is 1307, at
64 which time Switzerland is under rule by the Emperor Albert of
65 Habsburg. His local governor -- the vogt -- is the bullying Hermann
66 Gessler, who has placed his hat atop a wooden pole in the centre of
67 the town square; everybody who passes through the square must bow to
68 this hated symbol of imperial might...
70 Clearly, there's more to writing IF than just laying down the words in the
71 right order. Fortunately, we can make one immediate simplification: the
72 translated form produced by the Inform compiler -- those cryptic numbers
73 and letters held in what's known as the :term:`story file` -- is designed
74 to be read by the interpreter program. The story file is an example of a
75 "binary" file, containing data intended for use only by a computer program.
76 Forget all that unreadable gibberish.
78 So that leaves just the first form -- the one starting "``Constant Story``"
79 -- which represents the tale written as a piece of IF. That's the
80 :term:`source file` (so called because it contains the game in its
81 original, source, form) which you create on your computer. The source file
82 is a "text" (or "ASCII") file containing words and phrases which can be
83 read -- admittedly after a little tuition, which is what this guide is all
86 How do you create that source file? Using a third software program: an
87 :term:`editor`. However, unlike the compiler and interpreter, this program
88 isn't dedicated to the Inform system -- or even to IF. An editor is an
89 entirely general tool for creating and modifying text files; you've
90 probably already got a basic one on your computer (an IBM PC running
91 Windows comes with NotePad, while an Apple Macintosh has SimpleText or
92 TextEdit), or you can download a better one from the Internet. An editor
93 is like a word-processing program such as MS Word, only much less complex;
94 no fancy formatting features, no bold or italics or font control, no
95 embedded graphics; it simply enables you to type lines of text, which is
96 exactly what's needed to create an IF game.
98 If you look at the game source above, or in :doc:`/appendices/c`, you'll
99 notice ``Include "Parser";`` and ``Include "VerbLib";`` a few lines down
100 from the top of the file. These are instructions to the Inform compiler to
101 "include" -- that is, to merge in the contents -- of files called
102 ``Parser.h`` and ``VerbLib.h``. These are not files which you have to
103 create; they're standard :term:`library files`, part of the Inform system.
104 All that you have to do is remember to Include them in every game that you
105 write. Until you've a fair understanding of how Inform works, you've no
106 need to worry about what they contain (though you can look if you want to:
107 they're readable text files, just like the ones this guide will teach you
110 So, we've now introduced all of the bits and pieces which you need in order to
111 write an Inform adventure game:
113 * a text :term:`editor` program which can create and modify the
114 :term:`source file` containing the descriptions and definitions of your
115 game. Although it's not recommended, you can even use a word-processing
116 program to do this, but you have to remember to save your game in Text
119 * some Inform :term:`library files` which you Include in your own game
120 source file in order to provide the :term:`model world` -- a basic game
121 environment and lots of useful standard definitions;
123 * the Inform :term:`compiler` program, which reads your source file (and
124 the library files) and translates your descriptions and definitions into
125 another format -- the :term:`story file` -- intended only for...
127 * an Inform :term:`interpreter` program, which is what players of your game
128 use. A player doesn't require the source file, library files or compiler
129 program, just the interpreter and the game in compiled format (which,
130 because it's a binary file not meaningful to human eyes, neatly
131 discourages players from cheating).
133 All of those, apart from the editor, can be downloaded for free from the IF
134 Archive. One approach is to fetch them individually, following the
135 guidance on Graham's page: visit http://www.inform-fiction.org/ and look
136 for the "Software" section. However, if you're using a PC or a Mac, you'll
137 find it easier to download a complete package containing everything that
138 you need to get started.
142 Inform on an IBM PC (running Microsoft Windows)
143 ===============================================
145 Although the Windows operating system is upgraded on a fairly regular
146 basis, its basic capabilities and ways of working have remained
147 more-or-less consistent for many years. The information here applies to
148 PCs running Windows 95 onwards.
150 .. rubric:: Installing and testing Inform
154 1. Download http://www.firthworks.com/roger/downloads/inform_pc_env.zip to
155 a temporary location on your PC.
157 2. Use a tool like WinZip to unzip the downloaded file, giving you a new
158 ``Inform`` folder. Move this folder (and its contents) to a suitable
159 location on your PC -- a good place would be ``C:\My Documents\Inform``,
160 but you could also use ``C:\Documents and Settings\yourname\My
161 Documents\Inform``, ``C:\Inform`` or ``C:\Program Files\Inform``. You
162 should now have this set of folders:
164 .. image:: /images/inform_pc_env.*
167 In order to make the download small and fast, these folders include just
168 enough to get you started as an Inform designer -- the compiler and
169 interpreter programs, the library files, the ``Ruins.inf`` example file
170 from the |DM4|, and a template for your own first game. A few other
171 folders are included as placeholders where you could later download
172 additional components, if you wanted them. As soon as possible, you
173 should download the |DM4| into the ``Inform\Doc`` folder -- it's an
174 essential document to have, and has been omitted from this download only
175 because of its 3MB size.
177 3. To verify that the downloaded files work properly, use Windows Explorer
178 to display the contents of the ``Inform\Games\MyGame1`` folder: you will
179 see the two files ``MyGame1.bat`` and ``MyGame1.inf``:
181 .. image:: /images/filelist1.*
184 ``MyGame1.inf`` is a tiny skeleton game in Inform source format. By
185 convention, all Inform source files have an extension of .inf; Windows
186 has an inbuilt definition for ``.inf`` files, and so shows its Type as
187 "Setup Information", but this doesn't seem to matter. If you
188 double-click the file, it should open in NotePad so that you can see how
189 it's written, though it probably won't mean much -- yet.
191 4. ``MyGame1.bat`` is an MS-DOS batch file (an old kind of text-only
192 computer program, from the days before point-and-click interfaces) which
193 runs the Inform compiler. Double-click it; a DOS window opens as the
194 game compiles, and you'll see this::
196 C:\My Documents\Inform\Games\MyGame1>..\..\Lib\Base\Inform MyGame1
197 +include_path=.\,..\..\Lib\Base,..\..\Lib\Contrib | more
199 Inform 6.30 for Win32 (27th Feb 2004)
201 C:\My Documents\Inform\Games\MyGame1>pause "at end of compilation"
202 Press any key to continue . . .
204 Press the space bar, then close the DOS window.
208 On Windows NT, 2000 and XP, the DOS window closes of its own accord
209 when you press the space bar.
211 5. A story file ``MyGame1.z5`` has appeared in the folder; this is the
212 compiled game, which you can play using an interpreter:
214 .. image:: /images/filelist2.*
217 The extension of ``.z5`` signifies that the story file contains a
218 Z-machine game in Version 5 (today's standard) format.
220 6. Use Windows Explorer to display the contents of the ``Inform\Bin\Frotz``
221 folder, and double-click ``Frotz.exe``; the interpreter presents an
222 ``Open a Z-code Game`` dialog box.
224 7. Browse to display the ``Inform\Games\MyGame1`` folder, and select
225 ``MyGame1.z5``. Click ``Open``. The game starts running in the Windows
228 8. When you tire of "playing" the game -- which won't take long -- you can
229 type the QUIT command, you can select ``File > Exit``, or you can simply
230 close the Frotz window.
232 9. Using the same techniques, you can compile and play ``Ruins.inf``, which
233 is held in the ``Inform\Games\Download`` folder. RUINS is the game used
234 as an example throughout the |DM4|.
236 .. rubric:: Setting file associations
238 The business of first starting the interpreter, and then locating the story
239 file that you want to play, is clumsy and inconvenient. Fortunately, when
240 you first run the Frotz interpreter, it automatically creates an
241 association with story files whose extension is ``.z5``. From now on,
242 you'll be able to play a game simply by double-clicking its story file. If
243 some any reason this doesn't work, you can set up the association yourself:
245 1. Double-click ``MyGame1.z5``; Windows asks you to select the program
248 * type ``Z-code V5 Adventure`` as the "``Description for...``"
249 * click to select "``Always use this program...``"
252 2. Browse to display the ``Inform\Bin\Frotz`` folder, and select
253 ``Frotz.exe``. Click ``Open``.
255 .. rubric:: Changing the Windows icon
257 If the Windows icon that's displayed alongside ``MyGame1.z5`` doesn't look
258 right, you can change it.
260 1. In Windows Explorer, either select ``View > Options...`` and click
261 ``File Types``, or select ``Tools > Folder Options...`` and click ``File
264 * select the game file type in the list, which is in order either of
265 application (Frotz) or of extension (Z5)
268 2. In the ``Edit File Type`` dialog, click ``Change Icon``.
270 3. In the ``Change Icon`` dialog, ensure that the file name is
271 ``Inform\Bin\Frotz\Frotz.exe``, and select one of the displayed icons.
272 Click ``OK`` to close all the dialogs. The files in the folder should
275 .. image:: /images/filelist3.*
278 .. rubric:: Compiling using a batch file
280 You can view -- and of course change -- the contents of ``MyGame1.bat``,
281 the batch file which you double-click to run the compiler, using any text
282 editor. You'll see two lines, something like this (the first chunk is all
283 on one long line, with a space between the ``MyGame1`` and the
286 ..\..\Lib\Base\Inform MyGame1
287 +include_path=.\,..\..\Lib\Base,..\..\Lib\Contrib | more
288 pause "at end of compilation"
290 These long strings of text are command lines -- a powerful interface method
291 predating the icons and menus that most computer users know. You won't
292 need to master the command line interface in order to start using Inform,
293 but this section will tell you what these particular command lines are
294 doing. There are four parts to the first line:
296 1. ``Inform`` refers to the compiler program, and ``..\..\Lib\Base`` is the
297 name of the folder which contains it (addressed relative to *this*
298 folder, the one which holds the source file). Double-dots stand for "go
299 to the parent folder".
301 2. ``MyGame1`` is the name of the Inform source file; you don't need to
302 mention its extension of ``.inf`` if you don't want to.
304 3. ``+include_path=.\,..\..\Lib\Base,..\..\Lib\Contrib`` tells the compiler
305 where to look for files like ``Parser`` and ``VerbLib`` which you've
306 Included. Three locations are suggested: this folder, which holds the
307 source file (``.\``); the folder holding the standard library files
308 (``..\..\Lib\Base``); the folder holding useful bits and pieces
309 contributed by the Inform community (``..\..\Lib\Contrib``). The three
310 locations are searched in that order.
314 On the command line, you sometimes also see a compiler :term:`switch`
315 such as :option:`-S`, used for controlling detailed aspects of how
316 the compiler operates. Rather than do that here, we find it more
317 convenient to place any necessary switches at the very top of the
318 source file, as we'll explain in the next chapter.
320 4. ``| more`` causes the compiler to pause if it finds more mistakes than
321 it can tell you about on a single screen, rather than have them scroll
322 off the top of the MS-DOS window. Press the space bar to continue the
325 The second line -- ``pause "at end of compilation"`` -- just prevents the
326 window from closing before you can read its contents, as it otherwise would
327 on Windows NT, 2000 and XP.
329 You'll need to have a new batch file like this to match each new source
330 file which you create. The only item which will differ in the new file is
331 the name of the Inform source file -- ``MyGame1`` in this example. You
332 must change this to match the name of the new source file; everything else
333 can stay the same in each ``.bat`` file that you create.
335 .. rubric:: Getting a better editor
337 Although NotePad is adequate when you're getting started, you'll find life
338 much easier if you obtain a more powerful editor program. We recommend
339 TextPad, available as shareware from http://www.textpad.com/; in addition,
340 there are some detailed instructions at
341 http://www.onyxring.com/informguide.aspx?article=14 on how to improve the
342 way that TextPad works with Inform. The biggest single improvement, the
343 one that will make game development dramatically simpler, is being able to
344 compile your source file *from within* the editor. No need to save the
345 file, switch to another window and double-click the batch file (and indeed,
346 no further need for the batch file itself): just press a key while editing
347 the file -- and it compiles there and then. You can also run the
348 interpreter with similar ease. The convenience of doing this far outweighs
349 the small amount of time needed to obtain and configure TextPad.
353 Inform on an Apple Macintosh (running OS X)
354 ===========================================
356 Whereas our instructions for using Inform on a PC apply to just about all
357 versions of Windows, on the Macintosh we need to be more precise. Our
358 guidance here is specifically for Mac OS X, rather than for its predecessor
359 OS 9, and it may be helpful if we first mention a few relevant differences.
361 Mac OS X is a robust system constructed around -- or on top of -- BSD
362 [#bsd]_ UNIX. There are several kinds of applications that will run on
365 * Aqua: specifically designed for the Graphical User Interface of Mac OS X,
366 and taking advantage of its underlying technologies. Broadly, there
367 are two types of Aqua application:
369 * Cocoa: built with programming tools designed for Mac OS X.
371 * Carbon: built with the programming tools designed for Mac OS 9 and
372 earlier versions, but "translated" to take advantage of OS X.
374 * Classic: designed to work on Mac OS 9 and earlier versions. They need to
375 run in the Classic environment of OS X; roughly speaking, Classic is an
376 emulation of the older Mac systems.
378 * X11: based on a windowing system designed for the UNIX/Linux world. They
379 need an X-Windows server to run, and their appearance and functionality
380 may seem a lot different to what the Aqua user expects.
382 * UNIX: most UNIX programs (including Linux) will run on your Mac OS X, but
383 they usually have to be accessed (or configured) from the UNIX core of
384 your Mac, through the Terminal utility.
386 These differences may be significant, since some of the tools designed to
387 develop and run IF on a Mac system (for example, ones you'll find in the
388 Archive) have been built by programmers working in different environments
389 with varying technologies. We have tried to select tools that will make
390 your life easy as a beginner, but in time you may want to investigate
391 alternative approaches.
393 .. rubric:: Installing and testing Inform
397 1. Download http://www.firthworks.com/roger/downloads/inform_macosx_env.sit
398 to a temporary location on your Mac.
400 2. Use a tool like StuffIt Expander to unpack the downloaded file (if your
401 system configuration is standard, a mere double-click will make it
402 self-extract at the current location, if it hasn't already expanded all
403 by itself). You'll now have a new ``Inform`` folder. Move this folder
404 (and its contents) to a suitable location in your Mac.
408 It is a good idea for now to place it in your home directory;
409 otherwise, a few pre-configured items may not work as explained.
410 Once you learn the basics of the configuration, you may move the
411 Inform folder to a different location and hack all the defaults like
412 the professionals do.
414 You should now have this set of folders:
416 .. image:: /images/inform_mac_env.*
419 In order to make the download small and fast, these folders include just
420 enough to get you started as an Inform designer -- the compiler and
421 interpreter programs, the library files, the ``Ruins.inf`` example from
422 the |DM4|, and a template for your own first game, which you may copy
423 and rename each time you begin a new Inform project. A few other
424 folders are included as placeholders where you could later download
425 additional components, if you wanted them. As soon as possible, you
426 should download the |DM4| into the ``Inform/Doc`` folder -- it's an
427 essential document to have, and has been omitted from this download only
428 because of its 3MB size.
430 3. To verify that the downloaded files work properly, use the Finder to
431 display the contents of the ``Inform/Games/MyGame1`` folder: you will see
432 the files ``MyGame1.command`` and ``MyGame1.inf``:
434 .. image:: /images/mac_filelist1.*
437 ``MyGame1.inf`` is a tiny skeleton game in Inform source format. By
438 convention, all Inform source files have an extension of ``.inf``.
439 However, Mac OS X may show its Kind as "FUJI BAS IMG document", and try
440 to open it with GraphicConverter. If you're not a regular user of FUJI
441 BAS IMG documents, you'll probably want to change this. Either:
443 * right-click on the file (or Ctrl-click)
445 * select ``Open with`` and choose ``Other...``
447 * in the ``Open with`` dialog, go to the ``Applications`` folder and
450 * click to select "``Always open with``"
456 * right-click on the file (or Ctrl-click)
458 * press Option, select ``Always open with`` and choose ``Other...``
460 * in the ``Open with`` dialog, go to the ``Applications`` folder and
465 Now, if you double-click the file, it should open in TextEdit so that
466 you can see how it's written, though it probably won't mean much -- yet.
470 The above process may affect only this specific file. To change
471 the program that opens by default *all* ``.inf`` files, try this:
473 * right-click on the file (or Ctrl-click)
475 * select ``Get Info``
477 * in the ``Open with`` tab, select TextEdit as the application
479 * click the ``Change All...`` button, and confirm the change when asked.
481 4. ``MyGame1.command`` is a Terminal Shell Script (a UNIX executable
482 command-line file, a kind of text-only computer program from the days
483 before point-and-click interfaces) which runs the Inform compiler.
484 Double-click it; a UNIX window opens as the game compiles, and you'll
485 see something like this (the working path will reflect your folder
488 Last login: Sat Jul 3 03:07:51 on ttyp1
490 /Users/Dave/Inform/Games/MyGame1/MyGame1.command; [Hal:~] Dave%
491 /Users/Dave/Inform/Games/MyGame1/MyGame1.command; exit
492 Inform 6.30 (27th Feb 2004)
498 Verify this output. It's what's in the PDF, but the command prompt
499 looks like it's in the wrong place.
501 5. A story file ``MyGame1.z5`` has appeared in the folder; this is the
502 compiled game, which you can play using an interpreter:
504 .. image:: /images/mac_filelist2.*
507 The extension of ``.z5`` signifies that the story file contains a
508 Z-machine game in Version 5 (today's standard) format.
510 6. Use the Finder to display the contents of the ``Inform/Bin/Zoom``
511 folder, and double-click ``Zoom``; the interpreter presents an ``Open``
514 7. Browse to display the ``Inform/Games/MyGame1`` folder, and select
515 ``MyGame1.z5``. Click ``Open``. The game starts running in the Zoom
518 8. When you tire of "playing" the game -- which won't take long -- you can
519 type the QUIT command, you can select ``Zoom > Quit Zoom``, or you can
520 simply close the Zoom window.
522 .. rubric:: Setting file associations
524 The business of first starting the interpreter, and then locating the story
525 file that you want to play, is clumsy and inconvenient. Fortunately, when
526 the system first "sees" the Zoom interpreter (which is a nice Aqua
527 application) it automatically creates an association with story files whose
528 extension is ``.z5`` (and with other Infocom formats). From now on, you'll
529 be able to play a game simply by double-clicking its story file.
531 The files in the folder should now look like this:
533 .. image:: /images/mac_filelist3.*
536 .. rubric:: Compiling using a command-line file
538 If you have followed these instructions to configure your system, every
539 time that you need to compile your source code you just have to
540 double-click on the file ``MyGame1.command``. However, this file is good
541 only for this folder and for ``MyGame1.inf``.
543 If you want to start coding another game, you may copy the folder
544 ``MyGame1`` with all its contents and rename it as you please (for example,
545 ``MyGame2`` or something more appropriate). Inside the folder, you'll also
546 want to rename the relevant files:
548 ``MyGame1.inf`` might become ``MyGame2.inf``, or ``MobyDick.inf``,
551 ``MyGame1.command`` would change to match: ``MyGame2.command``, or
552 ``MobyDick.command``.
554 You can view -- and of course change -- the contents of
555 ``MyGame2.command``, the command file which you double-click to run the
556 compiler, using any text editor. You'll see two lines, something like this
557 (the second chunk is all on one long line, with a space between the
558 ``MyGame1`` and the ``+include_path``)::
560 cd ~/Inform/Games/MyGame1/
561 ../../Lib/Base/inform630_macosx MyGame1
562 +include_path=./,../../Lib/Base,../../Lib/Contrib
564 These long strings of text are command lines -- a powerful interface method
565 predating the icons and menus that most computer users know. You won't
566 need to master the command line interface in order to start using Inform,
567 but this section will introduce you to a few basic concepts to get your
568 bearings. The first line changes the working directory to
569 ``~/Inform/Games/MyGame1/``. The command ``cd`` (also known as ``chdir``,
570 short for "Change Directory to") lets you travel to the desired folder,
571 specified by the path, in this case: ``~/Inform/Games/MyGame1/``. The
572 ``~`` symbol stands for your home directory. That is, if your user name
573 were Dave, the above path is equal to::
575 /Users/Dave/Inform/Games/MyGame1/
577 You want to change that line so that it reads: ``cd
578 ~/Inform/Games/MyGame2/``
580 There are three parts to the second line:
582 1. ``inform630_macosx`` refers to the compiler program, and
583 ``../../Lib/Base`` is the name of the folder which contains it
584 (addressed relative to *this* folder, the one which holds the source
585 file). Double-dots stand for "go to the parent folder".
587 2. ``MyGame1`` is the name of the Inform source file; you don't need to
588 mention its extension of ``.inf`` if you don't want to. You'll want to
589 change this to match the name of your new file: ``MyGame2``.
591 3. ``+include_path=./,../../Lib/Base,../../Lib/Contrib`` tells the compiler
592 where to look for files like ``Parser`` and ``VerbLib`` which you've
593 Included in the source file (this may sound confusing now, but it will
594 make a lot of sense after you've delved a bit deeper into this Guide).
595 Three locations are suggested, separated by commas: this folder, which
596 holds the source file (``./``); the folder holding the standard library
597 files (``../../Lib/Base``); the folder holding useful bits and pieces
598 contributed by the Inform community (``../../Lib/Contrib``). The three
599 locations are searched in that order.
603 On the command line, you sometimes also see a compiler :term:`switch`
604 such as :option:`-S`, used for controlling detailed aspects of how
605 the compiler operates. Rather than do that here, we find it more
606 convenient to place any necessary switches at the very top of the
607 source file, as we'll explain in the next chapter.
609 Once you've finished editing those lines, ``Save`` the file (not
610 ``SaveAs``), overwriting the original, and make sure that your text editor
611 doesn't append an extension like ``.txt`` (TextEdit, the default editor
612 that comes with OS X, is polite enough to ask you about this).
614 You'll need to have a new command file like this to match each new source
615 file which you create. The only item which will differ in the new file is
616 the name of the Inform source file -- ``MyGameN``. You must change this to
617 match the name of the new source file; everything else can stay the same in
618 each ``.command`` file that you create.
620 .. rubric:: Making your own command-line file
622 There are two peculiarities by which your system understands that
623 ``MyGame1.command`` is a Terminal Shell Script. One is the extension
624 ``.command``, and the other is an attribute of the file which marks it as
625 "executable" (the "executable bits"). If it doesn't meet both conditions,
626 ``MyGame1.command`` won't run as it should. You have to be careful when
627 editing this file: if you were, for instance, to open it in a text editor
628 and save it to a different location with a different name, the executable
629 bits might get lost, and when you double-click it, you would see:
631 .. image:: /images/mac_exec_error.*
634 To make a command file from scratch (also, to fix this problem) you can
637 1. Open any text editor and write (using your own path)::
639 cd ~/Inform/Games/MyGameN/
640 ../../Lib/Base/inform630_macosx MyGameN
641 +include_path=./,../../Lib/Base,../../Lib/Contrib
643 where ``MyGameN`` stands for the name you have chosen for your Inform
646 2. Save the file in the folder ``MyGameN`` and call it ``MyGameN.command``.
647 Make sure that the text editor doesn't append a ``.txt`` extension; if
648 it does, rename the file manually.
650 3. Go to ``Applications > Utilities`` and double-click on ``Terminal``.
651 This opens the utility which provides you with a set of windows to
652 access the UNIX command line. Supposing the computer is named Hal, and
653 the user Dave, you should see something like this::
655 Last login: Wed Jun 30 18:05:55 on ttyp1
659 4. Every time that you open a Terminal window, you're at your home
660 directory (as noted by the tilde after the computer's name). You can
661 travel to your working folder by typing::
663 cd Inform/Games/MyGameN
665 You'll see how the path changes::
667 [Hal:~/Inform/Games/MyGameN] Dave%
669 Now you can make the command file executable with::
671 chmod 777 MyGameN.command
673 5. Alternatively, you can omit the cd command if you give the full path to
676 chmod 777 ~/Inform/Games/MyGameN/MyGameN.command
678 This sets the executable bits for the file ``MyGameN.command``.
680 6. Close the Terminal window.
682 Now, every time you need to compile your game, you can just double-click on
683 ``MyGameN.command`` from the Finder.
685 .. rubric:: Getting a better editor
687 Although TextEdit is adequate when you're getting started, you'll find life
688 much easier if you obtain a more powerful editor program. We'd really like
689 to recommend one -- there's an exciting list of possibilities at
690 http://osx.hyperjeff.net/Apps/apps.php?sub=5 -- but at the time of writing
691 none of them seems outstandingly suited to IF authorship. If you find one
692 that works really well, please let us know.
694 .. rubric:: More about the editor
696 As well as the ones that we recommend, other good text editors are listed
697 at http://www.firthworks.com/roger/editors/. One feature that's well worth
698 looking out for is "hotkey compilation" -- being able to run the compiler
699 from *within* the editor. Another is "syntax colouring", where the editor
700 understands enough of Inform's syntax rules to colour-code your source
701 file; for example: red for brackets, braces and parentheses ``[ ]`` ``{ }``
702 and ``( )``, blue for reserved words like ``Object`` and ``print``, green
703 for items in quotes like '...' and "...", and so on. Syntax colouring is
704 of great assistance in getting your source file correct and thus avoiding
705 silly compilation errors.
707 .. rubric:: More about the compiler
709 The Inform compiler is a powerful but undramatic software tool; it does an
710 awful lot of work, but it does it all at once, without stopping to ask you
711 any questions. Its input is a readable text source file; the output is a
712 story file, also sometimes known as a :term:`Z-code file` (because it
713 contains the game translated into code for the Z-machine, which we describe
714 in the next section).
716 If you're lucky, the compiler will translate your source file into Z-code;
717 perhaps surprisingly, it doesn't display any form of "success" message when
718 it succeeds. Often, however, it fails, because of mistakes which you've
719 made when writing the game. Inform defines a set of rules -- a capital
720 letter here, a comma there, these words only in a certain order, those
721 words spelled just so -- about which the compiler is extremely fussy. If
722 you accidentally break the rules, the compiler complains: it refuses to
723 write a Z-code file. *Do not worry about this*: the rules are easy to
724 learn, but just as easy to break, and all Inform designers inadvertently do
725 so on a regular basis. There's some additional information about dealing
726 with these mistakes, and about controlling how the compiler behaves, in
729 .. rubric:: More about the interpreter
731 One of the big advantages of the way Inform works is that a compiled game
732 -- the Z-code story file -- is portable between different computers.
733 That's not just from one PC to another: exactly the same story file will
734 run on a PC, a Mac, an Amiga, UNIX workstations, IBM mainframes, PalmOS
735 hand-helds, and on dozens of other past, present and future computers. The
736 magic that makes this happen is the interpreter program, a software tool
737 which pretends to be a simple computer called a :term:`Z-machine`. The
738 Z-machine is an imaginary (or "virtual") computer, but its design has been
739 very carefully specified, so that an expert programmer can quite easily
740 build one. And that's exactly what has happened: a Macintosh guru has
741 built an Inform interpreter which runs on Apple Macs, a UNIX wizard has
742 built one for UNIX workstations, and so on. Sometimes, you even get a
743 choice; for popular machines like the PC and the Mac there are several
744 interpreters available. And the wonderful thing is: each of those
745 interpreters, on each of those computers, is able to play every Inform game
746 that's ever been written *and*, as a surprise bonus, all of the classic
747 1980s Infocom games like "Zork" and "The Hitchhiker's Guide to the Galaxy"
750 (Actually, that last sentence is a slight exaggeration; a few games are
751 very large, or have pictures included within them, and not all interpreters
752 can handle this. However, with that small pinch of salt, it's pretty
755 That's enough waffling: let's get started! It's time to begin designing
758 .. rubric:: Footnotes
761 "BSD" stands for Berkeley Software Distribution, the name of the UNIX
762 derivative distributed in the 1970s from the University of California,
763 Berkeley, and used collectively for the modern descendants of those