| blob | 030e739f142df482e1eb155aa05cc78b8c205494 |
1 .TH GROFF_TMAC @MAN5EXT@ "@MDATE@" "Groff Version @VERSION@"
2 .SH NAME
3 groff_tmac \- macro files in the roff typesetting system
4 .SH DESCRIPTION
5 .\" The .SH was moved to this place to make `apropos' happy.
6 .
7 .
8 .\" --------------------------------------------------------------------
9 .\" Legalize
10 .\" --------------------------------------------------------------------
11 .
12 .ig
13 groff_tmac.5
15 File position: <groff-source>/man/groff_tmac.man
17 Last update: 27 Jul 2004
19 This file is part of groff, the GNU roff type-setting system.
21 Copyright (C) 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
22 written by Bernd Warken <bwarken@mayn.de> and Werner Lemberg
23 <wl@gnu.org>
25 Permission is granted to copy, distribute and/or modify this document
26 under the terms of the GNU Free Documentation License, Version 1.1 or
27 any later version published by the Free Software Foundation; with the
28 Invariant Sections being this .ig-section and AUTHOR, with no
29 Front-Cover Texts, and with no Back-Cover Texts.
31 A copy of the Free Documentation License is included as a file called
32 FDL in the main directory of the groff source package.
33 ..
34 .
35 .\" --------------------------------------------------------------------
36 .\" Setup
37 .\" --------------------------------------------------------------------
38 .
39 .do nr groff_tmac_C \n[.C]
40 .cp 0
41 .
42 .mso www.tmac
43 .
44 .if n \{\
45 . mso tty-char.tmac
46 . ftr CR R
47 . ftr CI I
48 . ftr CB B
49 .\}
50 .
51 .ds Ellipsis \&.\|.\|.\&\"
52 .
53 .\" Global static variables for inter-macro communication
54 .rr @+Example_font
55 .
56 .\" --------------------------------------------------------------------
57 .\" setup for the macro definitions below
58 .\"
59 .\" naming: namespace:cathegory_macro.variable_name (experimental)
60 .
61 .\" --------------------------------------------------------------------
62 .\" configuration of prompt for `.Shell_cmd'* macros
63 .ds groffer:Shell_cmd.prompt_text sh#\" prompt for shell commands
64 .ds groffer:Shell_cmd+.prompt_text >\" prompt on continuation lines
65 .ds groffer:Shell_cmd_base.prompt_font I\" font for prompts
66 .
67 .\" automatically determine setup from the configuration above
68 .als @f groffer:Shell_cmd_base.prompt_font\"
69 .als @t groffer:Shell_cmd.prompt_text\"
70 .als @t+ groffer:Shell_cmd+.prompt_text\"
71 .ds groffer:Shell_cmd.prompt \f[\*[@f]]\*[@t]\f[]\" needed
72 .ds groffer:Shell_cmd+.prompt \f[\*[@f]]\*[@t+]\f[]\" needed
73 .nr @w \w'\*[groffer:Shell_cmd.prompt]'\"
74 .nr @w+ \w'\*[groffer:Shell_cmd+.prompt]'\"
75 .ft \*[@f]
76 .\" Full prompt width is maximum of texts plus 1m
77 .nr groffer:Shell_cmd_base.prompt_width (\n[@w]>?\n[@w+]+1m)\" needed
78 .ft
79 .rm @f
80 .rm @f+
81 .rm @t
82 .rm @t+
83 .rr @w
84 .rr @w+
85 .
86 .\"--------------------------------------------------------------------
87 .\" Ignore all arguments like a comment, even after a .eo call.
88 .de c
89 ..
90 .c --------------------------------------------------------------------
91 .de BIR
92 . ie (\\n[.$] < 3) \
93 . BI \\$@
94 . el \{\
95 . ds @tmp@ \fB\\$1\f[]\fI\\$2\f[]
96 . shift 2
97 . Text \\*[@tmp@]\fR\\$*\f[]
98 . rm @tmp@
99 . \}
100 ..
101 .c --------------------------------------------------------------------
102 .c .Env_var (<env_var_name> [<punct>])
103 .c
104 .c Display an environment variable, with optional punctuation.
105 .c
106 .de Env_var
107 . nh
108 . SM
109 . Text \f[CB]\\$1\f[]\\$2
110 . hy
111 ..
112 .c --------------------------------------------------------------------
113 .c .Error (<text>...)
114 .c
115 .c Print error message to terminal and abort.
116 .c
117 .de Error
118 . tm \\$*
119 . ab
120 ..
121 .c --------------------------------------------------------------------
122 .de Example
123 . if r@+Example_font \
124 . Error previous .Example was not terminated by a ./Example
125 . nr @+Example_font \\n[.f]
126 . nh
127 . nf
128 . RS
129 . ft CR
130 ..
131 .c --------------------------------------------------------------------
132 .de /Example
133 . if !r@+Example_font \
134 . Error no previous call to .Example
135 . ft \\n[@+Example_font]
136 . RE
137 . fi
138 . hy
139 . rr @+Example_font
140 ..
141 .
142 .c --------------------------------------------------------------------
143 .c .Shell_cmd (<CR> [<CI>] ...)
144 .c
145 .c A shell command line; display args alternating in fonts CR and CI.
146 .c
147 .c Examples:
148 .c .Shell_cmd "groffer --dpi 100 file"
149 .c result: `sh# groffer --dpi 100 file'
150 .c with 'sh#' in font I, the rest in CR
151 .c
152 .c .Shell_cmd groffer\~--dpi\~100\~file
153 .c result: the same as above
154 .c
155 .c .Shell_cmd "groffer --dpi=" value " file"
156 .c result: sh# groffer --dpi=value file
157 .c with `groffer --dpi=' and `file' in CR; `value' in CI
158 .c
159 .c .Shell_cmd groffer\~--dpi= value \~file
160 .c result: the same as the previous example
161 .c
162 .de Shell_cmd
163 . groffer:Shell_cmd_base "\*[groffer:Shell_cmd.prompt]" \\$@
164 ..
165 .c --------------------------------------------------------------------
166 .c .Shell_cmd+ (<CR> [<CI>] ...)
167 .c
168 .c A continuation line for .Shell_cmd.
169 .c
170 .de Shell_cmd+
171 . groffer:Shell_cmd_base "\*[groffer:Shell_cmd+.prompt]" \\$@
172 ..
173 .c --------------------------------------------------------------------
174 .c .Shell_cmd_base (<prompt> [<CR> [<CI>] ...])
175 .c
176 .c A shell command line; display args alternating in fonts CR and CI.
177 .c Internal, do not use directly.
178 .c
179 .c Globals: read-only register @.Shell_cmd_width
180 .c
181 .de groffer:Shell_cmd_base
182 . if (\\n[.$] <= 0) \
183 . return
184 . nr @+font \\n[.f]\"
185 . ds @prompt \\$1\"
186 . ft CR
187 . c gap between prompt and command
188 . nr @+gap \\n[groffer:Shell_cmd_base.prompt_width]-\\w'\\*[@prompt]'\"
189 . ds @res \\*[@prompt]\h'\\n[@+gap]u'\"
190 . shift
191 . ds @cf CR\"
192 . while (\\n[.$] > 0) \{\
193 . as @res \\f[\\*[@cf]]\\$1\"
194 . shift
195 . ie '\\*[@cf]'CR' \
196 . ds @cf I\"
197 . el \
198 . ds @cf CR\"
199 . \}
200 . br
201 . ad l
202 . nh
203 . nf
204 . Text \\*[@res]\"
205 . fi
206 . hy
207 . ad
208 . br
209 . ft \\n[@+font]
210 . rr @+font
211 . rr @+gap
212 . rm @cf
213 . rm @res
214 ..
215 .c --------------------------------------------------------------------
216 .c .Text (<text>...)
217 .c
218 .c Treat the arguments as text, no matter how they look.
219 .c
220 .de Text
221 . if (\\n[.$] == 0) \
222 . return
223 . nop \)\\$*\)
224 ..
225 .c --------------------------------------------------------------------
226 .c .Topic ([<indent>])
227 .c
228 .c A bulleted paragraph
229 .c
230 .de Topic
231 . ie (\\n[.$] = 0) \
232 . ds @indent 2m\"
233 . el \
234 . ds @indent \\$1\"
235 . TP \\*[@indent]
236 . Text \[bu]
237 . rm @indent
238 ..
239 .c --------------------------------------------------------------------
240 .c .TP+ ()
241 .c
242 .c Continuation line for .TP header.
243 .c
244 .de TP+
245 . br
246 . ns
247 . TP \\$1
248 ..
249 .c --------------------------------------------------------------------
250 .de 'char
251 . ds @tmp@ `\f(CR\\$1\f[]'
252 . shift
253 . Text \\*[@tmp@]\\$*
254 . rm @tmp@
255 ..
256 .c --------------------------------------------------------------------
257 .de option
258 . ds @tmp@ \f(CB\\$1\f[]
259 . shift 1
260 . Text \\*[@tmp@]\\$*
261 . rm @tmp@
262 ..
263 .c --------------------------------------------------------------------
264 .de argument
265 . ds @tmp@ \f(CI\\$1\f[]
266 . shift 1
267 . Text \\*[@tmp@]\\$*
268 . rm @tmp@
269 ..
270 .c --------------------------------------------------------------------
271 .de request
272 . ds @tmp@ \f(CB\\$1\f[]
273 . shift 1
274 . Text .\\*[@tmp@]\\$*
275 . rm @tmp@
276 ..
277 .c --------------------------------------------------------------------
278 .de escape
279 . ds @tmp@ \f[CB]\\$1\f[]
280 . shift 1
281 . Text \[rs]\\*[@tmp@]\\$*
282 . rm @tmp@
283 ..
284 .\" --------------------------------------------------------------------
285 .\" SH DESCRIPTION
286 .\" --------------------------------------------------------------------
287 .
288 The
289 .BR roff (@MAN7EXT@)
290 type-setting system provides a set of macro packages suitable for
291 special kinds of documents.
292 .
293 Each macro package stores its macros and definitions in a file called
294 the package's
295 .BR "tmac file" .
296 The name is deduced from
297 .RB ` T\c
298 .IB roff MAC\c
299 .IR ros '.
300 .
301 .P
302 The tmac files are normal roff source documents, except that they
303 usually contain only definitions and setup commands, but no text.
304 .
305 All tmac files are kept in a single or a small number of directories,
306 the
307 .B tmac
308 directories.
309 .
310 .
311 .\" --------------------------------------------------------------------
312 .SH "GROFF MACRO PACKAGES"
313 .\" --------------------------------------------------------------------
314 .
315 .I groff
316 provides all classical macro packages, some more full packages, and
317 some secondary packages for special purposes.
318 .
319 Note that it is not possible to use multiple primary macro packages at the
320 same time; saying e.g.\&
321 .
322 .IP
323 .Shell_cmd "groff \-m man \-m ms foo"
324 .
325 .P
326 or
327 .
328 .IP
329 .Shell_cmd "groff \-m man foo \-m ms bar"
330 .
331 .P
332 will fail.
333 .
334 .
335 .\" --------------------------------------------------------------------
336 .SS "Man\~Pages"
337 .\" --------------------------------------------------------------------
338 .
339 .TP
340 .B man
341 This is the classical macro package for UNIX manual pages
342 (man\~pages); it is quite handy and easy to use; see
343 .BR groff_man (@MAN7EXT@).
344 .
345 .
346 .TP
347 .B doc
348 .TP+
349 .B mdoc
350 An alternative macro package for man\~pages mainly used in BSD
351 systems; it provides many new features, but it is not the standard for
352 man\~pages; see
353 .BR groff_mdoc (@MAN7EXT@).
354 .
355 .
356 .\" --------------------------------------------------------------------
357 .SS "Full Packages"
358 .\" --------------------------------------------------------------------
359 .
360 The packages in this section provide a complete set of macros for
361 writing documents of any kind, up to whole books.
362 .
363 They are similar in functionality; it is a matter of taste which one
364 to use.
365 .
366 .
367 .TP
368 .B me
369 The classical
370 .I me
371 macro package; see
372 .BR groff_me (@MAN7EXT@).
373 .
374 .
375 .TP
376 .B mm
377 The semi-classical
378 .I mm
379 macro package; see
380 .BR groff_mm (@MAN7EXT@).
381 .
382 .
383 .TP
384 .B mom
385 The new
386 .I mom
387 macro package, only available in groff.
388 .
389 As this is not based on other packages, it can be freely designed.
390 .
391 So it is expected to become quite a nice, modern macro package.
392 .
393 See
394 .BR groff_mom (@MAN7EXT@).
395 .
396 .
397 .TP
398 .B ms
399 The classical
400 .I ms
401 macro package; see
402 .BR groff_ms (@MAN7EXT@).
403 .
404 .
405 .\" --------------------------------------------------------------------
406 .SS "Special Packages"
407 .\" --------------------------------------------------------------------
408 .
409 The macro packages in this section are not intended for stand-alone
410 usage, but can be used to add special functionality to any other
411 macro package or to plain groff.
412 .
413 .
414 .TP
415 .B papersize
416 This macro file is already loaded at start-up by
417 .B @g@troff
418 so it isn't necessary to call it explicitly.
419 .
420 It provides an interface to set the paper size on the command line with
421 the option \f[B]\%\-dpaper=\f[]\f[I]size\f[].
422 .
423 Possible values for
424 .I size
425 are the same as the predefined
426 .B papersize
427 values in the DESC file (only lowercase; see
428 .BR groff_font (@MAN5EXT@)
429 for more) except
430 .BR a7 - d7 .
431 .
432 An appended
433 .B l
434 (ell) character denotes landscape orientation.
435 .
436 Examples:
437 .BR a4 ,
438 .BR c3l ,
439 .BR letterl .
440 .
441 .IP
442 Most output drivers need additional command line switches
443 .B \-p
444 and
445 .B \-l
446 to override the default paper length and orientation as set in the driver
447 specific DESC file.
448 .
449 For example, use the following for PS output on A4 paper in landscape
450 orientation:
451 .
452 .IP
453 .Shell_cmd "groff \-Tps \-dpaper=a4l \-P\-pa4 \-P\-l \-ms foo.ms > foo.ps"
454 .
455 .
456 .TP
457 .B pic
458 This file provides proper definitions for the macros
459 .B PS
460 and
461 .BR PE ,
462 needed for the
463 .BR @g@pic (@MAN1EXT@)
464 preprocessor.
465 .
466 They will center each picture.
467 .
468 Use it only if your macro package doesn't provide proper definitions
469 for those two macros (actually, most of them already have).
470 .
471 .
472 .TP
473 .B pspic
474 A single macro is provided in this file,
475 .BR PSPIC ,
476 to include a PostScript graphic in a document.
477 .
478 It makes only sense for output devices which support inclusion of PS
479 images:
480 .BR \-Tps ,
481 .BR \-Tdvi ,
482 and
483 .BR \-Thtml ;
484 the file is then loaded automatically.
485 .
486 Syntax:
487 .RS
488 .IP
489 \&\fB.PSPIC\fP [\fB\-L\fP|\fB-R\fP|\fB\-I\fP \fIn\fP]\ \fI\|file\fP [\fIwidth\fP [\fIheight\fP]]
490 .RE
491 .
492 .IP
493 .I file
494 is the name of the file containing the illustration;
495 .I width
496 and
497 .I height
498 give the desired width and height of the graphic.
499 .
500 The
501 .I width
502 and
503 .I height
504 arguments may have scaling indicators attached;
505 the default scaling indicator is\~\c
506 .BR i .
507 .
508 This macro will scale the graphic uniformly
509 in the x and y\~directions so that it is no more than
510 .I width
511 wide
512 and
513 .I height
514 high.
515 .
516 By default, the graphic will be horizontally centered.
517 .
518 The
519 .BI \-L
520 and
521 .BI \-R
522 options cause the graphic to be left-aligned and right-aligned,
523 respectively.
524 .
525 The
526 .B \-I
527 option causes the graphic to be indented by\~\c
528 .I n
529 (default scaling indicator is\~\c
530 .BR m ).
531 .
532 .
533 .TP
534 .B trace
535 Use this for tracing macro calls.
536 .
537 It is only useful for debugging.
538 .
539 See
540 .BR groff_trace (@MAN7EXT@) .
541 .
542 .
543 .TP
544 .B tty-char
545 Overrides the definition of standard troff characters and some groff
546 characters for tty devices.
547 .
548 The optical appearance is intentionally inferior compared to that of
549 normal tty formatting to allow processing with critical equipment.
550 .
551 .
552 .TP
553 .B www
554 Additions of elements known from the html format, as being used in the
555 internet (World Wide Web) pages; this includes URL links and mail
556 addresses; see
557 .BR groff_www (@MAN7EXT@).
558 .
559 .
560 .\" --------------------------------------------------------------------
561 .SH NAMING
562 .\" --------------------------------------------------------------------
563 .
564 In classical roff systems, there was a funny naming scheme for macro
565 packages, due to a simplistic design in option parsing.
566 .
567 Macro packages were always included by option
568 .option -m;
569 when this option was directly followed by its argument without an
570 intervening space, this looked like a long option preceded by a single
571 minus \[em] a sensation in the computer stone age.
572 .
573 To make this optically working for macro package names, all classical
574 macro packages choose a name that started with the letter
575 .'char m ,
576 which was omitted in the naming of the macro file.
577 .
578 .
579 .P
580 For example, the macro package for the man pages was called
581 .IR man ,
582 while its macro file
583 .IR tmac.an .
584 So it could be activated by the argument
585 .I an
586 to option
587 .option -m ,
588 or
589 .option -man
590 for short.
591 .
592 .
593 .P
594 For similar reasons, macro packages that did not start with an
595 .'char m
596 had a leading
597 .'char m
598 added in the documentation and in talking; for example, the package
599 corresponding to
600 .I tmac.doc
601 was called
602 .I mdoc
603 in the documentation, although a more suitable name would be
604 .IR doc .
605 For, when omitting the space between the option and its argument, the
606 command line option for activating this package reads
607 .option "-mdoc" .
608 .
609 .
610 .P
611 To cope with all situations, actual versions of
612 .BR groff (@MAN1EXT@)
613 are smart about both naming schemes by providing two macro files
614 for the inflicted macro packages; one with a leading
615 .'char m ,
616 the other one without it.
617 .
618 So in
619 .IR groff ,
620 the
621 .I man
622 macro package may be specified as on of the following four methods:
623 .
624 .IP
625 .Shell_cmd "groff\~\-m\~man"
626 .Shell_cmd "groff\~\-man"
627 .Shell_cmd "groff\~\-mman"
628 .Shell_cmd "groff\~\-m\~an"
629 .
630 .
631 .P
632 Recent packages that do not start with
633 .'char m
634 do not use an additional
635 .'char m
636 in the documentation.
637 .
638 For example, the
639 .I www
640 macro package may be specified only as one of the two methods:
641 .
642 .IP
643 .Shell_cmd "groff\~\-m\~www"
644 .Shell_cmd "groff\~\-mwww"
645 .
646 .
647 .P
648 Obviously, variants like
649 .I -mmwww
650 would not make much sense.
651 .
652 .
653 .P
654 A second strange feature of classical troff was to name macro files
655 according to
656 .BIR tmac. name .
657 In modern operating systems, the type of a file is specified as
658 postfix, the file name extension.
659 .
660 Again, groff copes with this situation by searching both
661 .IB anything .tmac
662 and
663 .BI tmac. anything
664 if only
665 .I anything
666 is specified.
667 .
668 .
669 .P
670 The easiest way to find out which macro packages are available on a
671 system is to check the man\~page
672 .BR groff (@MAN1EXT@),
673 or the contents of the
674 .I tmac
675 directories.
676 .
677 .
678 .P
679 In
680 .IR groff ,
681 most macro packages are described in\~man pages called
682 .BR groff_\f[I]name\f[] (@MAN7EXT@),
683 with a leading
684 .'char m
685 for the classical packages.
686 .
687 .
688 .\" --------------------------------------------------------------------
689 .SH INCLUSION
690 .\" --------------------------------------------------------------------
691 .
692 There are several ways to use a macro package in a document.
693 .
694 The classical way is to specify the troff/groff option
695 .option \-m
696 .argument name
697 at run-time; this makes the contents of the macro package
698 .I name
699 available.
700 .
701 In groff, the file
702 .IB name .tmac
703 is searched within the tmac path; if not found,
704 .BI tmac. name
705 will be searched for instead.
706 .
707 .
708 .P
709 Alternatively, it is also possible to include a macro file by adding
710 the request
711 .request so
712 .I filename
713 into the document; the argument must be the full file name of an
714 existing file, possibly with the directory where it is kept.
715 .
716 In groff, this was improved by the similar request
717 .request mso
718 .IR package ,
719 which added searching in the tmac path, just like option
720 .option -m
721 does.
722 .
723 .
724 .P
725 Note that in order to resolve the
726 .request so
727 and
728 .request mso
729 requests, the roff preprocessor
730 .BR soelim (@MAN1EXT@)
731 must be called if the files to be included need preprocessing.
732 .
733 This can be done either directly by a pipeline on the command line or
734 by using the troff/groff option
735 .option \-s .
736 .
737 .I man
738 calls soelim automatically.
739 .
740 .
741 .P
742 For example, suppose a macro file is stored as
743 .I @MACRODIR@/macros.tmac
744 and is used in some document called
745 .IR docu.roff .
746 .
747 .
748 .P
749 At run-time, the formatter call for this is
750 .
751 .IP
752 .Shell_cmd "groff\~\-m\~" "macrofile\~document.roff"
753 .
754 .
755 .P
756 To include the macro file directly in the document either
757 .
758 .IP
759 .Example
760 . Text .mso macrofile.tmac
761 ./Example
762 .
763 .P
764 is used or
765 .
766 .IP
767 .Example
768 . Text .so @MACRODIR@/macros.tmac
769 ./Example
770 .
771 .
772 .P
773 In both cases, the formatter is called with
774 .IP
775 .Shell_cmd "groff\~\-s\~" docu.roff
776 .
777 .
778 .P
779 If you want to write your own groff macro file, call it
780 .IB whatever .tmac
781 and put it in some directory of the tmac path, see section
782 .BR FILES .
783 Then documents can include it with the
784 .request mso
785 request or the option
786 .option -m .
787 .
788 .
789 .ig
790 .\" --------------------------------------------------------------------
791 .SH CONVENTION
792 .\" --------------------------------------------------------------------
793 .
794 .\" This section does not fit into the framework of this document.
795 .
796 There is a convention that is supported by many modern roff
797 type-setters and
798 .BR man (1)
799 programs, the
800 .I preprocessor word
801 described in the following.
802 .
803 .P
804 If the first line in a document is a comment, the first word (after the
805 comment characters and a blank) constitutes the
806 .B preprocessor
807 .BR word .
808 That means that the letters of this word are interpreted as
809 abbreviations for those preprocessor commands that should be run
810 when formatting the document.
811 .
812 Mostly, only the letters corresponding to the options for the
813 preprocessors are recognized,
814 .'char e
815 (for
816 .BR eqn ),
817 .\" 'char G ,
818 .\" 'char g ,
819 .'char p ,
820 (for
821 .BR pic ),
822 .'char R
823 (for
824 .BR refer ),
825 .'char s
826 (for
827 .BR soelim ),
828 and
829 .'char t
830 (for
831 .BR tbl ).
832 (see
833 .BR roff (@MAN7EXT@)).
834 .
835 .
836 .P
837 Besides being a good reminder for the user, some formatters (like the
838 .BR man (1)
839 program) are even able to automatically start the preprocessors
840 specified in the preprocessor word, but do not bet on this.
841 .
842 .
843 .P
844 The
845 .I man
846 program handles some preprocessors automatically, such that in
847 man\~pages only the following characters should be used:
848 .'char e ,
849 .'char p ,
850 and
851 .'char t .
852 .
853 .
854 ..
855 .\" --------------------------------------------------------------------
856 .SH "WRITING MACROS"
857 .\" --------------------------------------------------------------------
858 .
859 A
860 .BR roff (@MAN7EXT@)
861 document is a text file that is enriched by predefined formatting
862 constructs, such as requests, escape sequences, strings, numeric
863 registers, and macros from a macro package.
864 .
865 These elements are described in
866 .BR roff (@MAN7EXT@).
867 .
868 .
869 .P
870 To give a document a personal style, it is most useful to extend the
871 existing elements by defining some macros for repeating tasks; the best
872 place for this is near the beginning of the document or in a separate
873 file.
874 .
875 .
876 .P
877 Macros without arguments are just like strings.
878 .
879 But the full power of macros reveals when arguments are passed with a
880 macro call.
881 .
882 Within the macro definition, the arguments are available as the escape
883 sequences
884 .BR $1 ,
885 \*[Ellipsis],
886 .BR $9 ,
887 .BR $[ \*[Ellipsis] ] ,
888 .BR $* ,
889 and
890 .BR $@ ,
891 the name under which the macro was called is in
892 .BR $0 ,
893 and the number of arguments is in register
894 .BR \n[.$] ;
895 see
896 .BR groff (@MAN7EXT@).
897 .
898 .
899 .\" --------------------------------------------------------------------
900 .SS "Copy-in Mode"
901 .\" --------------------------------------------------------------------
902 .
903 The phase when groff reads a macro is called
904 .I "copy-in mode"
905 in roff-talk.
906 .
907 This is comparable to the C\~preprocessing phase during the development
908 of a program written in the C\~language.
909 .
910 .
911 .P
912 In this phase, groff interprets all backslashes; that means that all
913 escape sequences in the macro body are interpreted and replaced by
914 their value.
915 .
916 For constant expression, this is wanted, but strings and registers
917 that might change between calls of the macro must be protected from
918 being evaluated.
919 .
920 This is most easily done by doubling the backslash that introduces the
921 escape sequence.
922 .
923 This doubling is most important for the positional parameters.
924 .
925 For example, to print information on the arguments that were passed to
926 the macro to the terminal, define a macro named `.print_args',
927 say.
928 .
929 .
930 .P
931 .ds @1 \[rs]f[I]\[rs]\[rs]$0\[rs]f[]\"
932 .ds @2 arguments:\"
933 .Example
934 . Text .ds midpart was called with
935 . Text .de print_args
936 . Text .\~\~tm\~\*[@1]\~\[rs]\[rs]*[midpart]\~\[rs]\[rs]n[.$]\~\*[@2]
937 . Text .\~\~tm\~\[rs]\[rs]$*
938 . Text ..
939 ./Example
940 .rm @1
941 .rm @2
942 .
943 .
944 .P
945 When calling this macro by
946 .
947 .P
948 .Example
949 . Text .print_args arg1 arg2
950 ./Example
951 .
952 .P
953 the following text is printed to the terminal:
954 .
955 .P
956 .Example
957 . Text \f[CI]print_args\f[] was called with the following 2 arguments:
958 arg1 arg2
959 ./Example
960 .
961 .
962 .P
963 Let's analyze each backslash in the macro definition.
964 .
965 As the positional parameters and the number of arguments will change
966 with each call of the macro their leading backslash must be doubled,
967 which results in
968 .I \[rs]\[rs]$*
969 and
970 .IR \[rs]\[rs][.$] .
971 The same applies to the macro name because it could be called with an
972 alias name, so
973 .IR \[rs]\[rs]$0 .
974 .
975 .
976 .P
977 On the other hand,
978 .I midpart
979 is a constant string, it will not change, so no doubling for
980 .IR \[rs]*[midpart] .
981 The
982 .I \[rs]f
983 escape sequences are predefined groff elements for setting the font
984 within the text.
985 .
986 Of course, this behavior will not change, so no doubling with
987 .I \[rs]f[I]
988 and
989 .IR \[rs]f[] .
990 .
991 .
992 .\" --------------------------------------------------------------------
993 .SS "Draft Mode"
994 .\" --------------------------------------------------------------------
995 .
996 Writing groff macros is easy when the escaping mechanism is temporarily
997 disabled.
998 .
999 In groff, this is done by enclosing the macro definition(s) into a
1000 pair of
1001 .B .eo
1002 and
1003 .B .ec
1004 requests.
1005 .
1006 Then the body in the macro definition is just like a normal part of
1007 the document \[em] text enhanced by calls of requests, macros,
1008 strings, registers, etc.
1009 .
1010 For example, the code above can be written in a simpler way by
1011 .
1012 .
1013 .P
1014 .ds @1 \[rs]f[I]\[rs]$0\[rs]f[]\"
1015 .ds @2 arguments:\"
1016 .Example
1017 . Text .eo
1018 . Text .ds midpart was called with
1019 . Text .de print_args
1020 . Text .\~\~tm\~\*[@1]\~\[rs]*[midpart]\~\[rs]n[.$]\~\*[@2]
1021 . Text .\~\~tm\~\[rs]$*
1022 . Text ..
1023 . Text .ec
1024 ./Example
1025 .rm @1
1026 .rm @2
1027 .
1028 .
1029 .P
1030 Unfortunately, draft mode cannot be used universally.
1031 .
1032 Although it is good enough for defining normal macros, draft mode
1033 will fail with advanced applications, such as indirectly defined
1034 strings, registers, etc.
1035 .
1036 An optimal way is to define and test all macros in draft mode and then
1037 do the backslash doubling as a final step; do not forget to remove the
1038 .I .eo
1039 request.
1040 .
1041 .
1042 .\" --------------------------------------------------------------------
1043 .SS "Tips for Macro Definitions"
1044 .\" --------------------------------------------------------------------
1045 .
1046 .Topic
1047 Start every line with a dot, for example, by using the groff request
1048 .B .nop
1049 for text lines, or write your own macro that handles also text lines
1050 with a leading dot.
1051 .
1052 .IP
1053 .Example
1054 . Text .de Text
1055 . Text .\~\~if (\[rs]\[rs]n[.$] == 0)\~\[rs]
1056 . Text .\~\~\~\~return
1057 . Text .\~nop\~\[rs])\[rs]\[rs]$*[rs]\)
1058 . Text ..
1059 ./Example
1060 .
1061 .Topic
1062 Write a comment macro that works both for copy-in and draft mode; for
1063 as escaping is off in draft mode, trouble might occur when normal
1064 comments are used.
1065 .
1066 For example, the following macro just ignores its arguments, so it
1067 acts like a comment line:
1068 .
1069 .IP
1070 .Example
1071 . Text .de\~c
1072 . Text ..
1073 . Text .c\~This\~is\~like\~a\~comment\~line.
1074 ./Example
1075 .
1076 .Topic
1077 In long macro definitions, make ample use of comment lines or empty
1078 lines for a better structuring.
1079 .
1080 .Topic
1081 To increase readability, use groff's indentation facility for requests
1082 and macro calls (arbitrary whitespace after the leading dot).
1083 .
1084 .
1085 .\" --------------------------------------------------------------------
1086 .SS "Diversions"
1087 .\" --------------------------------------------------------------------
1088 .
1089 Diversions can be used to realize quite advanced programming
1090 constructs.
1091 .
1092 They are comparable to pointers to large data structures in the
1093 C\~programming language, but their usage is quite different.
1094 .
1095 .
1096 .P
1097 In their simplest form, diversions are multi-line strings, but
1098 they get their power when diversions are used dynamically within macros.
1099 .
1100 The information stored in a diversion can be retrieved by calling the
1101 diversion just like a macro.
1102 .
1103 .
1104 .P
1105 Most of the problems arising with diversions can be avoided if you are
1106 conscious about the fact that diversions always deal with complete
1107 lines.
1108 .
1109 If diversions are used when the line buffer has not been flashed,
1110 strange results are produced; not knowing this, many people get
1111 desperate about diversions.
1112 .
1113 To ensure that a diversion works, line breaks should be added at the
1114 right places.
1115 .
1116 To be on the secure side, enclose everything that has to do with
1117 diversions into a pair of line breaks; for example, by amply using
1118 .B .br
1119 requests.
1120 .
1121 This rule should be applied to diversion definition, both inside and
1122 outside, and to all calls of diversions.
1123 .
1124 This is a bit of overkill, but it works nicely.
1125 .
1126 .
1127 .P
1128 [If you really need diversions which should ignore the current partial
1129 line, use environments to save the current partial line and/\:or use the
1130 .B .box
1131 request.]
1132 .
1133 .
1134 .P
1135 The most powerful feature using diversions is to start a diversion
1136 within a macro definition and end it within another macro.
1137 .
1138 Then everything between each call of this macro pair is stored within
1139 the diversion and can be manipulated from within the macros.
1140 .
1141 .
1142 .\" --------------------------------------------------------------------
1143 .SH FILES
1144 .\" --------------------------------------------------------------------
1145 .
1146 All macro names must be named
1147 .IB name .tmac
1148 to fully use the tmac mechanism.
1149 .
1150 .BI tmac. name
1151 as with classical packages is possible as well, but deprecated.
1152 .
1153 .
1154 .P
1155 The macro files are kept in the
1156 .IR "tmac directories" ;
1157 a colon separated list of these constitutes the
1158 .IR "tmac path" .
1159 .
1160 .
1161 .P
1162 The search sequence for macro files is (in that order):
1163 .
1164 .Topic
1165 the directories specified with troff/groff's
1166 .B \-M
1167 command line option
1168 .
1169 .Topic
1170 the directories given in the
1171 .Env_var $GROFF_TMAC_PATH
1172 environment variable
1173 .
1174 .Topic
1175 the current directory (only if in unsafe mode, which is enabled by the
1176 .B \-U
1177 command line switch)
1178 .
1179 .Topic
1180 the home directory
1181 .
1182 .Topic
1183 a platform-specific directory, being
1184 .B @SYSTEMMACRODIR@
1185 in this installation
1186 .
1187 .Topic
1188 a site-specific (platform-independent) directory, being
1189 .B @LOCALMACRODIR@
1190 in this installation
1191 .
1192 .Topic
1193 the main tmac directory, being
1194 .B @MACRODIR@
1195 in this installation
1196 .
1197 .
1198 .\" --------------------------------------------------------------------
1199 .SH ENVIRONMENT
1200 .\" --------------------------------------------------------------------
1201 .
1202 .TP
1203 .Env_var $GROFF_TMAC_PATH
1204 A colon separated list of additional tmac directories in which to search
1205 for macro files.
1206 .
1207 See the previous section for a detailed description.
1208 .
1209 .
1210 .\" --------------------------------------------------------------------
1211 .SH AUTHOR
1212 .\" --------------------------------------------------------------------
1213 .
1214 Copyright (C) 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
1215 .
1216 .P
1217 This document is distributed under the terms of the FDL (GNU Free
1218 Documentation License) version 1.1 or later.
1219 .
1220 You should have received a copy of the FDL on your system, it is also
1221 available on-line at the
1222 .URL http://\:www.gnu.org/\:copyleft/\:fdl.html "GNU copyleft site" .
1223 .
1224 .P
1225 This document is part of
1226 .IR groff ,
1227 the GNU roff distribution.
1228 .
1229 It was written by
1230 .MTO bwarken@mayn.de "Bernd Warken" ;
1231 it is maintained by
1232 .MTO wl@gnu.org "Werner Lemberg" .
1233 .
1234 .
1235 .\" --------------------------------------------------------------------
1236 .SH "SEE ALSO"
1237 .\" --------------------------------------------------------------------
1238 .
1239 A complete reference for all parts of the groff system is found in the
1240 groff
1241 .BR info (1)
1242 file.
1243 .
1244 .
1245 .TP
1246 .BR groff (@MAN1EXT@)
1247 an overview of the groff system.
1248 .
1249 .
1250 .TP
1251 .BR groff_man (@MAN7EXT@),
1252 .TP+
1253 .BR groff_mdoc (@MAN7EXT@),
1254 .TP+
1255 .BR groff_me (@MAN7EXT@),
1256 .TP+
1257 .BR groff_mm (@MAN7EXT@),
1258 .TP+
1259 .BR groff_mom (@MAN7EXT@),
1260 .TP+
1261 .BR groff_ms (@MAN7EXT@),
1262 .TP+
1263 .BR groff_trace (@MAN7EXT@),
1264 .TP+
1265 .BR groff_www (@MAN7EXT@).
1266 the groff tmac macro packages.
1267 .
1268 .
1269 .TP
1270 .BR groff (@MAN7EXT@)
1271 the groff language.
1272 .
1273 .
1274 .P
1275 The Filesystem Hierarchy Standard is available at the
1276 .URL http://\:www.pathname.com/\:fhs/ "FHS web site" .
1277 .
1278 .cp \n[groff_tmac_C]
1279 .
1280 .\" Local Variables:
1281 .\" mode: nroff
1282 .\" End: