Annotation of mandoc/roff.7, Revision 1.52
1.52 ! schwarze 1: .\" $Id: roff.7,v 1.51 2014/03/30 21:28:01 schwarze Exp $
1.1 kristaps 2: .\"
1.46 schwarze 3: .\" Copyright (c) 2010, 2011, 2012 Kristaps Dzonsons <kristaps@bsd.lv>
1.47 schwarze 4: .\" Copyright (c) 2010, 2011, 2013, 2014 Ingo Schwarze <schwarze@openbsd.org>
1.1 kristaps 5: .\"
6: .\" Permission to use, copy, modify, and distribute this software for any
7: .\" purpose with or without fee is hereby granted, provided that the above
8: .\" copyright notice and this permission notice appear in all copies.
9: .\"
10: .\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11: .\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12: .\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13: .\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14: .\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15: .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16: .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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1.51 schwarze 18: .Dd $Mdocdate: March 30 2014 $
1.1 kristaps 19: .Dt ROFF 7
20: .Os
21: .Sh NAME
22: .Nm roff
1.17 schwarze 23: .Nd roff language reference for mandoc
1.1 kristaps 24: .Sh DESCRIPTION
25: The
26: .Nm roff
1.17 schwarze 27: language is a general purpose text formatting language.
1.33 schwarze 28: Since traditional implementations of the
1.17 schwarze 29: .Xr mdoc 7
30: and
31: .Xr man 7
1.33 schwarze 32: manual formatting languages are based on it,
33: many real-world manuals use small numbers of
1.17 schwarze 34: .Nm
1.46 schwarze 35: requests and escape sequences intermixed with their
1.33 schwarze 36: .Xr mdoc 7
37: or
38: .Xr man 7
39: code.
40: To properly format such manuals, the
1.1 kristaps 41: .Xr mandoc 1
1.33 schwarze 42: utility supports a tiny subset of
43: .Nm
1.46 schwarze 44: requests and escapes.
45: Only these requests and escapes supported by
1.33 schwarze 46: .Xr mandoc 1
47: are documented in the present manual,
48: together with the basic language syntax shared by
49: .Nm ,
50: .Xr mdoc 7 ,
51: and
52: .Xr man 7 .
53: For complete
54: .Nm
55: manuals, consult the
56: .Sx SEE ALSO
57: section.
1.1 kristaps 58: .Pp
1.33 schwarze 59: Input lines beginning with the control character
1.17 schwarze 60: .Sq \&.
1.33 schwarze 61: are parsed for requests and macros.
62: Such lines are called
63: .Dq request lines
1.1 kristaps 64: or
1.33 schwarze 65: .Dq macro lines ,
66: respectively.
67: Requests change the processing state and manipulate the formatting;
68: some macros also define the document structure and produce formatted
69: output.
70: The single quote
71: .Pq Qq \(aq
72: is accepted as an alternative control character,
73: treated by
74: .Xr mandoc 1
75: just like
76: .Ql \&.
77: .Pp
78: Lines not beginning with control characters are called
79: .Dq text lines .
80: They provide free-form text to be printed; the formatting of the text
81: depends on the respective processing context.
1.1 kristaps 82: .Sh LANGUAGE SYNTAX
83: .Nm
84: documents may contain only graphable 7-bit ASCII characters, the space
1.17 schwarze 85: character, and, in certain circumstances, the tab character.
1.38 kristaps 86: The backslash character
1.33 schwarze 87: .Sq \e
1.46 schwarze 88: indicates the start of an escape sequence, used for example for
1.33 schwarze 89: .Sx Comments ,
90: .Sx Special Characters ,
91: .Sx Predefined Strings ,
92: and
93: user-defined strings defined using the
94: .Sx ds
95: request.
1.46 schwarze 96: For a listing of escape sequences, consult the
97: .Sx ESCAPE SEQUENCE REFERENCE
98: below.
1.33 schwarze 99: .Ss Comments
100: Text following an escaped double-quote
101: .Sq \e\(dq ,
102: whether in a request, macro, or text line, is ignored to the end of the line.
103: A request line beginning with a control character and comment escape
104: .Sq \&.\e\(dq
105: is also ignored.
106: Furthermore, request lines with only a control character and optional
107: trailing whitespace are stripped from input.
108: .Pp
109: Examples:
110: .Bd -literal -offset indent -compact
111: \&.\e\(dq This is a comment line.
112: \&.\e\(dq The next line is ignored:
113: \&.
114: \&.Sh EXAMPLES \e\(dq This is a comment, too.
115: \&example text \e\(dq And so is this.
116: .Ed
117: .Ss Special Characters
118: Special characters are used to encode special glyphs and are rendered
119: differently across output media.
120: They may occur in request, macro, and text lines.
121: Sequences begin with the escape character
122: .Sq \e
123: followed by either an open-parenthesis
124: .Sq \&(
125: for two-character sequences; an open-bracket
126: .Sq \&[
127: for n-character sequences (terminated at a close-bracket
128: .Sq \&] ) ;
129: or a single one character sequence.
130: .Pp
131: Examples:
132: .Bl -tag -width Ds -offset indent -compact
133: .It Li \e(em
134: Two-letter em dash escape.
135: .It Li \ee
136: One-letter backslash escape.
137: .El
138: .Pp
139: See
1.17 schwarze 140: .Xr mandoc_char 7
1.33 schwarze 141: for a complete list.
142: .Ss Text Decoration
143: Terms may be text-decorated using the
144: .Sq \ef
145: escape followed by an indicator: B (bold), I (italic), R (regular), or P
146: (revert to previous mode).
147: A numerical representation 3, 2, or 1 (bold, italic, and regular,
148: respectively) may be used instead.
1.34 kristaps 149: The indicator or numerical representative may be preceded by C
150: (constant-width), which is ignored.
1.33 schwarze 151: .Pp
1.42 schwarze 152: The two-character indicator
153: .Sq BI
154: requests a font that is both bold and italic.
155: It may not be portable to old roff implementations.
156: .Pp
1.33 schwarze 157: Examples:
158: .Bl -tag -width Ds -offset indent -compact
159: .It Li \efBbold\efR
1.42 schwarze 160: Write in \fBbold\fP, then switch to regular font mode.
1.33 schwarze 161: .It Li \efIitalic\efP
1.42 schwarze 162: Write in \fIitalic\fP, then return to previous font mode.
163: .It Li \ef(BIbold italic\efP
164: Write in \f(BIbold italic\fP, then return to previous font mode.
1.33 schwarze 165: .El
166: .Pp
167: Text decoration is
168: .Em not
169: recommended for
170: .Xr mdoc 7 ,
171: which encourages semantic annotation.
172: .Ss Predefined Strings
173: Predefined strings, like
174: .Sx Special Characters ,
175: mark special output glyphs.
176: Predefined strings are escaped with the slash-asterisk,
177: .Sq \e* :
178: single-character
179: .Sq \e*X ,
180: two-character
181: .Sq \e*(XX ,
182: and N-character
183: .Sq \e*[N] .
184: .Pp
185: Examples:
186: .Bl -tag -width Ds -offset indent -compact
187: .It Li \e*(Am
188: Two-letter ampersand predefined string.
189: .It Li \e*q
190: One-letter double-quote predefined string.
191: .El
192: .Pp
193: Predefined strings are not recommended for use,
194: as they differ across implementations.
195: Those supported by
196: .Xr mandoc 1
197: are listed in
198: .Xr mandoc_char 7 .
199: Manuals using these predefined strings are almost certainly not portable.
200: .Ss Whitespace
201: Whitespace consists of the space character.
202: In text lines, whitespace is preserved within a line.
203: In request and macro lines, whitespace delimits arguments and is discarded.
204: .Pp
205: Unescaped trailing spaces are stripped from text line input unless in a
206: literal context.
207: In general, trailing whitespace on any input line is discouraged for
208: reasons of portability.
209: In the rare case that a blank character is needed at the end of an
210: input line, it may be forced by
211: .Sq \e\ \e& .
212: .Pp
213: Literal space characters can be produced in the output
214: using escape sequences.
215: In macro lines, they can also be included in arguments using quotation; see
216: .Sx MACRO SYNTAX
217: for details.
218: .Pp
219: Blank text lines, which may include whitespace, are only permitted
220: within literal contexts.
221: If the first character of a text line is a space, that line is printed
222: with a leading newline.
223: .Ss Scaling Widths
224: Many requests and macros support scaled widths for their arguments.
225: The syntax for a scaled width is
226: .Sq Li [+-]?[0-9]*.[0-9]*[:unit:] ,
227: where a decimal must be preceded or followed by at least one digit.
228: Negative numbers, while accepted, are truncated to zero.
229: .Pp
230: The following scaling units are accepted:
231: .Pp
232: .Bl -tag -width Ds -offset indent -compact
233: .It c
234: centimetre
235: .It i
236: inch
237: .It P
238: pica (~1/6 inch)
239: .It p
240: point (~1/72 inch)
241: .It f
242: synonym for
243: .Sq u
244: .It v
245: default vertical span
246: .It m
247: width of rendered
248: .Sq m
249: .Pq em
250: character
251: .It n
252: width of rendered
253: .Sq n
254: .Pq en
255: character
256: .It u
257: default horizontal span
258: .It M
259: mini-em (~1/100 em)
260: .El
261: .Pp
262: Using anything other than
263: .Sq m ,
264: .Sq n ,
265: .Sq u ,
266: or
267: .Sq v
268: is necessarily non-portable across output media.
269: See
270: .Sx COMPATIBILITY .
271: .Pp
272: If a scaling unit is not provided, the numerical value is interpreted
273: under the default rules of
274: .Sq v
275: for vertical spaces and
276: .Sq u
277: for horizontal ones.
278: .Pp
279: Examples:
280: .Bl -tag -width ".Bl -tag -width 2i" -offset indent -compact
281: .It Li \&.Bl -tag -width 2i
282: two-inch tagged list indentation in
283: .Xr mdoc 7
284: .It Li \&.HP 2i
285: two-inch tagged list indentation in
286: .Xr man 7
287: .It Li \&.sp 2v
288: two vertical spaces
289: .El
290: .Ss Sentence Spacing
291: Each sentence should terminate at the end of an input line.
292: By doing this, a formatter will be able to apply the proper amount of
293: spacing after the end of sentence (unescaped) period, exclamation mark,
294: or question mark followed by zero or more non-sentence closing
295: delimiters
296: .Po
297: .Sq \&) ,
298: .Sq \&] ,
299: .Sq \&' ,
300: .Sq \&"
301: .Pc .
302: .Pp
303: The proper spacing is also intelligently preserved if a sentence ends at
304: the boundary of a macro line.
305: .Pp
306: Examples:
307: .Bd -literal -offset indent -compact
308: Do not end sentences mid-line like this. Instead,
309: end a sentence like this.
310: A macro would end like this:
311: \&.Xr mandoc 1 \&.
312: .Ed
1.17 schwarze 313: .Sh REQUEST SYNTAX
314: A request or macro line consists of:
315: .Pp
316: .Bl -enum -compact
317: .It
318: the control character
319: .Sq \&.
1.1 kristaps 320: or
1.17 schwarze 321: .Sq \(aq
322: at the beginning of the line,
323: .It
324: optionally an arbitrary amount of whitespace,
325: .It
326: the name of the request or the macro, which is one word of arbitrary
327: length, terminated by whitespace,
328: .It
329: and zero or more arguments delimited by whitespace.
330: .El
331: .Pp
332: Thus, the following request lines are all equivalent:
1.1 kristaps 333: .Bd -literal -offset indent
1.17 schwarze 334: \&.ig end
335: \&.ig end
336: \&. ig end
1.1 kristaps 337: .Ed
1.24 schwarze 338: .Sh MACRO SYNTAX
1.33 schwarze 339: Macros are provided by the
340: .Xr mdoc 7
341: and
342: .Xr man 7
343: languages and can be defined by the
1.24 schwarze 344: .Sx \&de
345: request.
346: When called, they follow the same syntax as requests, except that
347: macro arguments may optionally be quoted by enclosing them
348: in double quote characters
349: .Pq Sq \(dq .
1.33 schwarze 350: Quoted text, even if it contains whitespace or would cause
351: a macro invocation when unquoted, is always considered literal text.
352: Inside quoted text, pairs of double quote characters
353: .Pq Sq Qq
354: resolve to single double quote characters.
355: .Pp
1.32 kristaps 356: To be recognised as the beginning of a quoted argument, the opening
1.24 schwarze 357: quote character must be preceded by a space character.
358: A quoted argument extends to the next double quote character that is not
359: part of a pair, or to the end of the input line, whichever comes earlier.
360: Leaving out the terminating double quote character at the end of the line
361: is discouraged.
362: For clarity, if more arguments follow on the same input line,
363: it is recommended to follow the terminating double quote character
364: by a space character; in case the next character after the terminating
365: double quote character is anything else, it is regarded as the beginning
366: of the next, unquoted argument.
367: .Pp
368: Both in quoted and unquoted arguments, pairs of backslashes
369: .Pq Sq \e\e
370: resolve to single backslashes.
371: In unquoted arguments, space characters can alternatively be included
372: by preceding them with a backslash
373: .Pq Sq \e\~ ,
374: but quoting is usually better for clarity.
1.33 schwarze 375: .Pp
376: Examples:
377: .Bl -tag -width Ds -offset indent -compact
378: .It Li .Fn strlen \(dqconst char *s\(dq
379: Group arguments
380: .Qq const char *s
381: into one function argument.
382: If unspecified,
383: .Qq const ,
384: .Qq char ,
385: and
386: .Qq *s
387: would be considered separate arguments.
388: .It Li .Op \(dqFl a\(dq
389: Consider
390: .Qq \&Fl a
391: as literal text instead of a flag macro.
392: .El
1.15 kristaps 393: .Sh REQUEST REFERENCE
1.17 schwarze 394: The
1.15 kristaps 395: .Xr mandoc 1
396: .Nm
1.32 kristaps 397: parser recognises the following requests.
1.17 schwarze 398: Note that the
1.15 kristaps 399: .Nm
1.17 schwarze 400: language defines many more requests not implemented in
1.15 kristaps 401: .Xr mandoc 1 .
402: .Ss \&ad
403: Set line adjustment mode.
404: This line-scoped request is intended to have one argument to select
1.32 kristaps 405: normal, left, right, or centre adjustment for subsequent text.
1.15 kristaps 406: Currently, it is ignored including its arguments,
407: and the number of arguments is not checked.
1.3 kristaps 408: .Ss \&am
1.15 kristaps 409: Append to a macro definition.
410: The syntax of this request is the same as that of
411: .Sx \&de .
412: It is currently ignored by
413: .Xr mandoc 1 ,
414: as are its children.
1.3 kristaps 415: .Ss \&ami
1.15 kristaps 416: Append to a macro definition, specifying the macro name indirectly.
417: The syntax of this request is the same as that of
418: .Sx \&dei .
419: It is currently ignored by
420: .Xr mandoc 1 ,
421: as are its children.
1.3 kristaps 422: .Ss \&am1
1.15 kristaps 423: Append to a macro definition, switching roff compatibility mode off
424: during macro execution.
425: The syntax of this request is the same as that of
426: .Sx \&de1 .
427: It is currently ignored by
428: .Xr mandoc 1 ,
429: as are its children.
1.47 schwarze 430: .Ss \&as
431: Append to a user-defined string.
432: The syntax of this request is the same as that of
433: .Sx \&ds .
434: If a user-defined string with the specified name does not yet exist,
435: it is set to the empty string before appending.
1.39 kristaps 436: .Ss \&cc
437: Changes the control character.
438: Its syntax is as follows:
439: .Bd -literal -offset indent
440: .Pf . Cm \&cc Op Ar c
441: .Ed
442: .Pp
443: If
444: .Ar c
445: is not specified, the control character is reset to
446: .Sq \&. .
447: Trailing characters are ignored.
1.47 schwarze 448: .Ss \&ce
449: Center some lines.
450: This line-scoped request is intended to take one integer argument,
451: specifying how many lines to center.
452: Currently, it is ignored including its arguments, and the number
453: of arguments is not checked.
1.3 kristaps 454: .Ss \&de
1.17 schwarze 455: Define a
1.15 kristaps 456: .Nm
457: macro.
458: Its syntax can be either
459: .Bd -literal -offset indent
460: .Pf . Cm \&de Ar name
461: .Ar macro definition
462: \&..
463: .Ed
464: .Pp
465: or
466: .Bd -literal -offset indent
467: .Pf . Cm \&de Ar name Ar end
468: .Ar macro definition
469: .Pf . Ar end
470: .Ed
471: .Pp
472: Both forms define or redefine the macro
473: .Ar name
474: to represent the
475: .Ar macro definition ,
476: which may consist of one or more input lines, including the newline
477: characters terminating each line, optionally containing calls to
478: .Nm
479: requests,
480: .Nm
481: macros or high-level macros like
482: .Xr man 7
483: or
484: .Xr mdoc 7
485: macros, whichever applies to the document in question.
486: .Pp
487: Specifying a custom
488: .Ar end
489: macro works in the same way as for
490: .Sx \&ig ;
491: namely, the call to
492: .Sq Pf . Ar end
493: first ends the
494: .Ar macro definition ,
495: and after that, it is also evaluated as a
496: .Nm
497: request or
498: .Nm
499: macro, but not as a high-level macro.
500: .Pp
1.17 schwarze 501: The macro can be invoked later using the syntax
1.15 kristaps 502: .Pp
503: .D1 Pf . Ar name Op Ar argument Op Ar argument ...
504: .Pp
1.24 schwarze 505: Regarding argument parsing, see
506: .Sx MACRO SYNTAX
507: above.
1.15 kristaps 508: .Pp
1.17 schwarze 509: The line invoking the macro will be replaced
1.15 kristaps 510: in the input stream by the
511: .Ar macro definition ,
512: replacing all occurrences of
513: .No \e\e$ Ns Ar N ,
1.17 schwarze 514: where
1.15 kristaps 515: .Ar N
516: is a digit, by the
517: .Ar N Ns th Ar argument .
518: For example,
519: .Bd -literal -offset indent
520: \&.de ZN
521: \efI\e^\e\e$1\e^\efP\e\e$2
522: \&..
523: \&.ZN XtFree .
524: .Ed
525: .Pp
526: produces
527: .Pp
528: .D1 \efI\e^XtFree\e^\efP.
529: .Pp
530: in the input stream, and thus in the output: \fI\^XtFree\^\fP.
531: .Pp
1.17 schwarze 532: Since macros and user-defined strings share a common string table,
1.15 kristaps 533: defining a macro
534: .Ar name
535: clobbers the user-defined string
536: .Ar name ,
537: and the
538: .Ar macro definition
539: can also be printed using the
540: .Sq \e*
541: string interpolation syntax described below
542: .Sx ds ,
543: but this is rarely useful because every macro definition contains at least
544: one explicit newline character.
1.16 schwarze 545: .Pp
546: In order to prevent endless recursion, both groff and
547: .Xr mandoc 1
548: limit the stack depth for expanding macros and strings
549: to a large, but finite number.
550: Do not rely on the exact value of this limit.
1.3 kristaps 551: .Ss \&dei
1.17 schwarze 552: Define a
1.15 kristaps 553: .Nm
554: macro, specifying the macro name indirectly.
1.17 schwarze 555: The syntax of this request is the same as that of
1.15 kristaps 556: .Sx \&de .
557: It is currently ignored by
558: .Xr mandoc 1 ,
559: as are its children.
560: .Ss \&de1
1.17 schwarze 561: Define a
1.15 kristaps 562: .Nm
563: macro that will be executed with
564: .Nm
565: compatibility mode switched off during macro execution.
566: This is a GNU extension not available in traditional
567: .Nm
568: implementations and not even in older versions of groff.
569: Since
570: .Xr mandoc 1
571: does not implement
572: .Nm
1.17 schwarze 573: compatibility mode at all, it handles this request as an alias for
1.15 kristaps 574: .Sx \&de .
1.6 schwarze 575: .Ss \&ds
1.15 kristaps 576: Define a user-defined string.
1.13 kristaps 577: Its syntax is as follows:
578: .Pp
1.15 kristaps 579: .D1 Pf . Cm \&ds Ar name Oo \(dq Oc Ns Ar string
1.13 kristaps 580: .Pp
581: The
1.15 kristaps 582: .Ar name
1.13 kristaps 583: and
1.15 kristaps 584: .Ar string
585: arguments are space-separated.
586: If the
587: .Ar string
588: begins with a double-quote character, that character will not be part
589: of the string.
590: All remaining characters on the input line form the
591: .Ar string ,
592: including whitespace and double-quote characters, even trailing ones.
593: .Pp
1.13 kristaps 594: The
1.15 kristaps 595: .Ar string
596: can be interpolated into subsequent text by using
597: .No \e* Ns Bq Ar name
598: for a
599: .Ar name
600: of arbitrary length, or \e*(NN or \e*N if the length of
601: .Ar name
602: is two or one characters, respectively.
1.17 schwarze 603: Interpolation can be prevented by escaping the leading backslash;
604: that is, an asterisk preceded by an even number of backslashes
605: does not trigger string interpolation.
1.15 kristaps 606: .Pp
607: Since user-defined strings and macros share a common string table,
608: defining a string
609: .Ar name
1.17 schwarze 610: clobbers the macro
1.15 kristaps 611: .Ar name ,
612: and the
613: .Ar name
614: used for defining a string can also be invoked as a macro,
615: in which case the following input line will be appended to the
616: .Ar string ,
617: forming a new input line passed to the
618: .Nm
619: parser.
620: For example,
621: .Bd -literal -offset indent
622: \&.ds badidea .S
623: \&.badidea
624: H SYNOPSIS
625: .Ed
626: .Pp
627: invokes the
628: .Cm SH
629: macro when used in a
630: .Xr man 7
631: document.
632: Such abuse is of course strongly discouraged.
1.5 kristaps 633: .Ss \&el
634: The
635: .Qq else
636: half of an if/else conditional.
637: Pops a result off the stack of conditional evaluations pushed by
638: .Sx \&ie
639: and uses it as its conditional.
640: If no stack entries are present (e.g., due to no prior
641: .Sx \&ie
642: calls)
643: then false is assumed.
1.17 schwarze 644: The syntax of this request is similar to
1.5 kristaps 645: .Sx \&if
646: except that the conditional is missing.
1.27 kristaps 647: .Ss \&EN
648: End an equation block.
649: See
650: .Sx \&EQ .
651: .Ss \&EQ
652: Begin an equation block.
653: See
654: .Xr eqn 7
655: for a description of the equation language.
1.43 schwarze 656: .Ss \&fam
657: Change the font family.
658: This line-scoped request is intended to have one argument specifying
659: the font family to be selected.
660: It is a groff extension, and currently, it is ignored including its
661: arguments, and the number of arguments is not checked.
1.49 schwarze 662: .Ss \&ft
663: Change the font.
664: Its syntax is as follows:
665: .Pp
666: .D1 Pf . Cm \&ft Op Ar font
667: .Pp
668: The following
669: .Ar font
670: arguments are supported:
671: .Bl -tag -width 4n -offset indent
672: .It Cm B , BI , 3 , 4
673: switches to
674: .Sy bold
675: font
676: .It Cm I , 2
677: switches to
678: .Em underlined
679: font
680: .It Cm R , CW , 1
681: switches to normal font
682: .It Cm P No "or no argument"
683: switches back to the previous font
684: .El
685: .Pp
686: This request takes effect only locally, may be overridden by macros
687: and escape sequences, and is only supported in
688: .Xr man 7
689: for now.
1.44 schwarze 690: .Ss \&hw
691: Specify hyphenation points in words.
692: This line-scoped request is currently ignored.
1.15 kristaps 693: .Ss \&hy
694: Set automatic hyphenation mode.
695: This line-scoped request is currently ignored.
1.5 kristaps 696: .Ss \&ie
697: The
698: .Qq if
699: half of an if/else conditional.
700: The result of the conditional is pushed into a stack used by subsequent
701: invocations of
702: .Sx \&el ,
703: which may be separated by any intervening input (or not exist at all).
704: Its syntax is equivalent to
705: .Sx \&if .
1.1 kristaps 706: .Ss \&if
1.7 schwarze 707: Begins a conditional.
1.48 schwarze 708: This request has the following syntax:
709: .Bd -literal -offset indent
710: \&.if COND BODY
711: .Ed
712: .Bd -literal -offset indent
713: \&.if COND \e{BODY
714: BODY...\e}
715: .Ed
716: .Bd -literal -offset indent
717: \&.if COND \e{\e
718: BODY...
719: \&.\e}
720: .Ed
721: .Pp
722: COND is a conditional statement.
723: Currently,
724: .Xr mandoc 1
725: supports the following subset of roff conditionals:
726: .Bl -bullet
727: .It
728: If
729: .Sq \&!
730: is prefixed to COND, the condition is logically inverted.
731: .It
732: If the first character of COND is
733: .Sq n
734: .Pq nroff mode
735: or
736: .Sq o
737: .Pq odd page ,
738: COND evaluates to true.
739: .It
740: If the first character of COND is
741: .Sq c
742: .Pq character available ,
743: .Sq d
744: .Pq string defined ,
745: .Sq e
746: .Pq even page ,
747: .Sq r
748: .Pq register accessed ,
749: or
750: .Sq t
751: .Pq troff mode ,
752: COND evaluates to false.
753: .It
754: If COND starts with a digit, optionally prefixed by a minus sign,
755: it is evaluated as a numerical expression of the form
756: .Ar number operator number ,
757: where
758: .Ar operator
759: is one of
760: .Sq < ,
761: .Sq <= ,
762: .Sq = ,
763: .Sq >= ,
764: or
765: .Sq > .
766: .It
767: Otherwise, the first character of COND is regarded as a delimiter
768: and COND evaluates to true if the string extending from its first
769: to its second occurrence is equal to the string extending from its
770: second to its third occurrence.
771: .It
772: If COND cannot be parsed, it evaluates to false.
773: .El
774: .Pp
1.3 kristaps 775: If a conditional is false, its children are not processed, but are
776: syntactically interpreted to preserve the integrity of the input
777: document.
778: Thus,
779: .Pp
1.17 schwarze 780: .D1 \&.if t .ig
1.3 kristaps 781: .Pp
782: will discard the
783: .Sq \&.ig ,
784: which may lead to interesting results, but
785: .Pp
1.17 schwarze 786: .D1 \&.if t .if t \e{\e
1.3 kristaps 787: .Pp
788: will continue to syntactically interpret to the block close of the final
789: conditional.
790: Sub-conditionals, in this case, obviously inherit the truth value of
791: the parent.
1.1 kristaps 792: .Pp
793: If the BODY section is begun by an escaped brace
794: .Sq \e{ ,
1.48 schwarze 795: scope continues until the end of the input line containing the
796: matching closing-brace escape sequence
797: .Sq \e} .
1.17 schwarze 798: If the BODY is not enclosed in braces, scope continues until
799: the end of the line.
1.1 kristaps 800: If the COND is followed by a BODY on the same line, whether after a
1.17 schwarze 801: brace or not, then requests and macros
1.1 kristaps 802: .Em must
803: begin with a control character.
804: It is generally more intuitive, in this case, to write
805: .Bd -literal -offset indent
806: \&.if COND \e{\e
807: \&.foo
808: bar
809: \&.\e}
810: .Ed
811: .Pp
1.17 schwarze 812: than having the request or macro follow as
1.1 kristaps 813: .Pp
814: .D1 \&.if COND \e{ .foo
815: .Pp
816: The scope of a conditional is always parsed, but only executed if the
817: conditional evaluates to true.
818: .Pp
1.29 kristaps 819: Note that the
1.1 kristaps 820: .Sq \e}
1.29 kristaps 821: is converted into a zero-width escape sequence if not passed as a
822: standalone macro
823: .Sq \&.\e} .
824: For example,
825: .Pp
826: .D1 \&.Fl a \e} b
827: .Pp
828: will result in
1.8 kristaps 829: .Sq \e}
1.29 kristaps 830: being considered an argument of the
831: .Sq \&Fl
832: macro.
1.1 kristaps 833: .Ss \&ig
1.2 kristaps 834: Ignore input.
1.15 kristaps 835: Its syntax can be either
836: .Bd -literal -offset indent
837: .Pf . Cm \&ig
838: .Ar ignored text
1.2 kristaps 839: \&..
840: .Ed
1.15 kristaps 841: .Pp
842: or
843: .Bd -literal -offset indent
844: .Pf . Cm \&ig Ar end
845: .Ar ignored text
846: .Pf . Ar end
1.2 kristaps 847: .Ed
848: .Pp
849: In the first case, input is ignored until a
850: .Sq \&..
1.17 schwarze 851: request is encountered on its own line.
1.15 kristaps 852: In the second case, input is ignored until the specified
853: .Sq Pf . Ar end
854: macro is encountered.
855: Do not use the escape character
1.2 kristaps 856: .Sq \e
1.15 kristaps 857: anywhere in the definition of
858: .Ar end ;
859: it would cause very strange behaviour.
860: .Pp
861: When the
862: .Ar end
863: macro is a roff request or a roff macro, like in
1.2 kristaps 864: .Pp
865: .D1 \&.ig if
866: .Pp
867: the subsequent invocation of
868: .Sx \&if
1.15 kristaps 869: will first terminate the
870: .Ar ignored text ,
871: then be invoked as usual.
872: Otherwise, it only terminates the
873: .Ar ignored text ,
874: and arguments following it or the
875: .Sq \&..
1.17 schwarze 876: request are discarded.
1.50 schwarze 877: .Ss \&ll
878: Change the output line length.
879: Its syntax is as follows:
880: .Pp
1.51 schwarze 881: .D1 Pf . Cm \&ll Op Oo +|- Oc Ns Ar width
1.50 schwarze 882: .Pp
883: If the
884: .Ar width
885: argument is omitted, the line length is reset to its previous value.
886: The default setting for terminal output is 78n.
1.51 schwarze 887: If a sign is given, the line length is added to or subtracted from;
888: otherwise, it is set to the provided value.
1.50 schwarze 889: Using this request in new manuals is discouraged for several reasons,
890: among others because it overrides the
891: .Xr mandoc 1
892: .Fl O Cm width
893: command line option.
1.15 kristaps 894: .Ss \&ne
895: Declare the need for the specified minimum vertical space
896: before the next trap or the bottom of the page.
897: This line-scoped request is currently ignored.
898: .Ss \&nh
899: Turn off automatic hyphenation mode.
900: This line-scoped request is currently ignored.
1.10 kristaps 901: .Ss \&nr
1.45 schwarze 902: Define or change a register.
1.10 kristaps 903: A register is an arbitrary string value that defines some sort of state,
904: which influences parsing and/or formatting.
905: Its syntax is as follows:
906: .Pp
1.45 schwarze 907: .D1 Pf \. Cm \&nr Ar name Oo +|- Oc Ns Ar value
1.10 kristaps 908: .Pp
909: The
1.15 kristaps 910: .Ar value
1.10 kristaps 911: may, at the moment, only be an integer.
1.46 schwarze 912: If it is prefixed by a sign, the register will be
1.45 schwarze 913: incremented or decremented instead of assigned to.
914: .Pp
915: The following register
1.15 kristaps 916: .Ar name
1.45 schwarze 917: is handled specially:
1.10 kristaps 918: .Bl -tag -width Ds
919: .It Cm nS
920: If set to a positive integer value, certain
921: .Xr mdoc 7
1.17 schwarze 922: macros will behave in the same way as in the
1.10 kristaps 923: .Em SYNOPSIS
1.11 kristaps 924: section.
1.17 schwarze 925: If set to 0, these macros will behave in the same way as outside the
926: .Em SYNOPSIS
927: section, even when called within the
1.10 kristaps 928: .Em SYNOPSIS
1.17 schwarze 929: section itself.
930: Note that starting a new
1.11 kristaps 931: .Xr mdoc 7
1.17 schwarze 932: section with the
933: .Cm \&Sh
934: macro will reset this register.
1.10 kristaps 935: .El
1.26 schwarze 936: .Ss \&ns
937: Turn on no-space mode.
938: This line-scoped request is intended to take no arguments.
939: Currently, it is ignored including its arguments,
940: and the number of arguments is not checked.
941: .Ss \&ps
942: Change point size.
943: This line-scoped request is intended to take one numerical argument.
944: Currently, it is ignored including its arguments,
945: and the number of arguments is not checked.
1.52 ! schwarze 946: .Ss \&rm
! 947: Remove a request, macro or string.
! 948: Its syntax is as follows:
! 949: .Pp
! 950: .D1 Pf \. Cm \&rm Ar name
! 951: .Ss \&rr
! 952: Remove a register.
! 953: Its syntax is as follows:
! 954: .Pp
! 955: .D1 Pf \. Cm \&rr Ar name
1.15 kristaps 956: .Ss \&so
957: Include a source file.
958: Its syntax is as follows:
959: .Pp
960: .D1 Pf \. Cm \&so Ar file
961: .Pp
962: The
963: .Ar file
964: will be read and its contents processed as input in place of the
965: .Sq \&.so
966: request line.
1.28 kristaps 967: To avoid inadvertent inclusion of unrelated files,
1.15 kristaps 968: .Xr mandoc 1
969: only accepts relative paths not containing the strings
970: .Qq ../
971: and
972: .Qq /.. .
1.37 schwarze 973: .Pp
974: This request requires
975: .Xr man 1
976: to change to the right directory before calling
977: .Xr mandoc 1 ,
978: per convention to the root of the manual tree.
979: Typical usage looks like:
980: .Pp
981: .Dl \&.so man3/Xcursor.3
982: .Pp
983: As the whole concept is rather fragile, the use of
984: .Sx \&so
985: is discouraged.
986: Use
987: .Xr ln 1
988: instead.
1.26 schwarze 989: .Ss \&ta
990: Set tab stops.
991: This line-scoped request can take an arbitrary number of arguments.
992: Currently, it is ignored including its arguments.
1.6 schwarze 993: .Ss \&tr
994: Output character translation.
1.30 kristaps 995: Its syntax is as follows:
996: .Pp
997: .D1 Pf \. Cm \&tr Ar [ab]+
998: .Pp
999: Pairs of
1000: .Ar ab
1001: characters are replaced
1002: .Ar ( a
1003: for
1004: .Ar b ) .
1005: Replacement (or origin) characters may also be character escapes; thus,
1006: .Pp
1007: .Dl tr \e(xx\e(yy
1008: .Pp
1009: replaces all invocations of \e(xx with \e(yy.
1.20 kristaps 1010: .Ss \&T&
1011: Re-start a table layout, retaining the options of the prior table
1012: invocation.
1013: See
1014: .Sx \&TS .
1015: .Ss \&TE
1016: End a table context.
1017: See
1018: .Sx \&TS .
1019: .Ss \&TS
1020: Begin a table, which formats input in aligned rows and columns.
1.23 kristaps 1021: See
1022: .Xr tbl 7
1023: for a description of the tbl language.
1.46 schwarze 1024: .Sh ESCAPE SEQUENCE REFERENCE
1025: The
1026: .Xr mandoc 1
1027: .Nm
1028: parser recognises the following escape sequences.
1029: Note that the
1030: .Nm
1031: language defines more escape sequences not implemented in
1032: .Xr mandoc 1 .
1033: In
1034: .Xr mdoc 7
1035: and
1036: .Xr man 7
1037: documents, using escape sequences is discouraged except for those
1038: described in the
1039: .Sx LANGUAGE SYNTAX
1040: section above.
1041: .Pp
1042: A backslash followed by any character not listed here
1043: simply prints that character itself.
1044: .Ss \e<newline>
1045: A backslash at the end of an input line can be used to continue the
1046: logical input line on the next physical input line, joining the text
1047: on both lines together as if it were on a single input line.
1048: .Ss \e<space>
1049: The escape sequence backslash-space
1050: .Pq Sq \e\ \&
1051: is an unpaddable space-sized non-breaking space character; see
1052: .Sx Whitespace .
1053: .Ss \e\(dq
1054: The rest of the input line is treated as
1055: .Sx Comments .
1056: .Ss \e%
1057: Hyphenation allowed at this point of the word; ignored by
1058: .Xr mandoc 1 .
1059: .Ss \e&
1060: Non-printing zero-width character; see
1061: .Sx Whitespace .
1062: .Ss \e\(aq
1063: Acute accent special character; use
1064: .Sq \e(aa
1065: instead.
1066: .Ss \e( Ns Ar cc
1067: .Sx Special Characters
1068: with two-letter names, see
1069: .Xr mandoc_char 7 .
1070: .Ss \e*[ Ns Ar name ]
1071: Interpolate the string with the
1072: .Ar name ;
1073: see
1074: .Sx Predefined Strings
1075: and
1076: .Sx ds .
1077: For short names, there are variants
1078: .No \e* Ns Ar c
1079: and
1080: .No \e*( Ns Ar cc .
1081: .Ss \e-
1082: Special character
1083: .Dq mathematical minus sign .
1084: .Ss \e[ Ns Ar name ]
1085: .Sx Special Characters
1086: with names of arbitrary length, see
1087: .Xr mandoc_char 7 .
1088: .Ss \e^
1089: One-twelfth em half-narrow space character, effectively zero-width in
1090: .Xr mandoc 1 .
1091: .Ss \e`
1092: Grave accent special character; use
1093: .Sq \e(ga
1094: instead.
1095: .Ss \e{
1096: Begin conditional input; see
1097: .Sx if .
1098: .Ss \e\(ba
1099: One-sixth em narrow space character, effectively zero-width in
1100: .Xr mandoc 1 .
1101: .Ss \e}
1102: End conditional input; see
1103: .Sx if .
1104: .Ss \e~
1105: Paddable non-breaking space character.
1106: .Ss \e0
1107: Digit width space character.
1108: .Ss \eA\(aq Ns Ar string Ns \(aq
1109: Anchor definition; ignored by
1110: .Xr mandoc 1 .
1111: .Ss \eB\(aq Ns Ar string Ns \(aq
1112: Test whether
1113: .Ar string
1114: is a numerical expession; ignored by
1115: .Xr mandoc 1 .
1116: .Ss \eb\(aq Ns Ar string Ns \(aq
1117: Bracket building function; ignored by
1118: .Xr mandoc 1 .
1119: .Ss \eC\(aq Ns Ar name Ns \(aq
1120: .Sx Special Characters
1121: with names of arbitrary length.
1122: .Ss \ec
1123: Interrupt text processing to insert requests or macros; ignored by
1124: .Xr mandoc 1 .
1125: .Ss \eD\(aq Ns Ar string Ns \(aq
1126: Draw graphics function; ignored by
1127: .Xr mandoc 1 .
1128: .Ss \ed
1129: Move down by half a line; ignored by
1130: .Xr mandoc 1 .
1131: .Ss \ee
1132: Backslash special character.
1133: .Ss \eF[ Ns Ar name ]
1134: Switch font family (groff extension); ignored by
1135: .Xr mandoc 1 .
1136: For short names, there are variants
1137: .No \eF Ns Ar c
1138: and
1139: .No \eF( Ns Ar cc .
1140: .Ss \ef[ Ns Ar name ]
1141: Switch to the font
1142: .Ar name ,
1143: see
1144: .Sx Text Decoration .
1145: For short names, there are variants
1146: .No \ef Ns Ar c
1147: and
1148: .No \ef( Ns Ar cc .
1149: .Ss \eg[ Ns Ar name ]
1150: Interpolate the format of a number register; ignored by
1151: .Xr mandoc 1 .
1152: For short names, there are variants
1153: .No \eg Ns Ar c
1154: and
1155: .No \eg( Ns Ar cc .
1156: .Ss \eH\(aq Ns Oo +|- Oc Ns Ar number Ns \(aq
1157: Set the height of the current font; ignored by
1158: .Xr mandoc 1 .
1159: .Ss \eh\(aq Ns Ar number Ns \(aq
1160: Horizontal motion; ignored by
1161: .Xr mandoc 1 .
1162: .Ss \ek[ Ns Ar name ]
1163: Mark horizontal input place in register; ignored by
1164: .Xr mandoc 1 .
1165: For short names, there are variants
1166: .No \ek Ns Ar c
1167: and
1168: .No \ek( Ns Ar cc .
1169: .Ss \eL\(aq Ns Ar number Ns Oo Ar c Oc Ns \(aq
1170: Vertical line drawing function; ignored by
1171: .Xr mandoc 1 .
1172: .Ss \el\(aq Ns Ar number Ns Oo Ar c Oc Ns \(aq
1173: Horizontal line drawing function; ignored by
1174: .Xr mandoc 1 .
1175: .Ss \eM[ Ns Ar name ]
1176: Set fill (background) color (groff extension); ignored by
1177: .Xr mandoc 1 .
1178: For short names, there are variants
1179: .No \eM Ns Ar c
1180: and
1181: .No \eM( Ns Ar cc .
1182: .Ss \em[ Ns Ar name ]
1183: Set glyph drawing color (groff extension); ignored by
1184: .Xr mandoc 1 .
1185: For short names, there are variants
1186: .No \em Ns Ar c
1187: and
1188: .No \em( Ns Ar cc .
1189: .Ss \eN\(aq Ns Ar number Ns \(aq
1190: Character
1191: .Ar number
1192: on the current font.
1193: .Ss \en[ Ns Ar name ]
1194: Interpolate the number register
1195: .Ar name .
1196: For short names, there are variants
1197: .No \en Ns Ar c
1198: and
1199: .No \en( Ns Ar cc .
1200: .Ss \eo\(aq Ns Ar string Ns \(aq
1201: Overstrike
1202: .Ar string ;
1203: ignored by
1204: .Xr mandoc 1 .
1205: .Ss \eR\(aq Ns Ar name Oo +|- Oc Ns Ar number Ns \(aq
1206: Set number register; ignored by
1207: .Xr mandoc 1 .
1208: .Ss \eS\(aq Ns Ar number Ns \(aq
1209: Slant output; ignored by
1210: .Xr mandoc 1 .
1211: .Ss \es\(aq Ns Oo +|- Oc Ns Ar number Ns \(aq
1212: Change point size; ignored by
1213: .Xr mandoc 1 .
1214: Alternative forms
1215: .No \es Ns Oo +|- Oc Ns Ar n ,
1216: .No \es Ns Oo +|- Oc Ns \(aq Ns Ar number Ns \(aq ,
1217: .No \es Ns [ Oo +|- Oc Ns Ar number ] ,
1218: and
1219: .No \es Ns Oo +|- Oc Ns [ Ar number Ns ]
1220: are also parsed and ignored.
1221: .Ss \et
1222: Horizontal tab; ignored by
1223: .Xr mandoc 1 .
1224: .Ss \eu
1225: Move up by half a line; ignored by
1226: .Xr mandoc 1 .
1227: .Ss \eV[ Ns Ar name ]
1228: Interpolate an environment variable; ignored by
1229: .Xr mandoc 1 .
1230: For short names, there are variants
1231: .No \eV Ns Ar c
1232: and
1233: .No \eV( Ns Ar cc .
1234: .Ss \ev\(aq Ns Ar number Ns \(aq
1235: Vertical motion; ignored by
1236: .Xr mandoc 1 .
1237: .Ss \ew\(aq Ns Ar string Ns \(aq
1238: Interpolate the width of the
1239: .Ar string ;
1240: ignored by
1241: .Xr mandoc 1 .
1242: .Ss \eX\(aq Ns Ar string Ns \(aq
1243: Output
1244: .Ar string
1245: as device control function; ignored in nroff mode and by
1246: .Xr mandoc 1 .
1247: .Ss \ex\(aq Ns Ar number Ns \(aq
1248: Extra line space function; ignored by
1249: .Xr mandoc 1 .
1250: .Ss \eY[ Ns Ar name ]
1251: Output a string as a device control function; ignored in nroff mode and by
1252: .Xr mandoc 1 .
1253: For short names, there are variants
1254: .No \eY Ns Ar c
1255: and
1256: .No \eY( Ns Ar cc .
1257: .Ss \eZ\(aq Ns Ar string Ns \(aq
1258: Print
1259: .Ar string
1260: with zero width and height; ignored by
1261: .Xr mandoc 1 .
1262: .Ss \ez
1263: Output the next character without advancing the cursor position;
1264: approximated in
1265: .Xr mandoc 1
1266: by simply skipping the next character.
1.2 kristaps 1267: .Sh COMPATIBILITY
1.40 schwarze 1268: This section documents compatibility between mandoc and other
1.17 schwarze 1269: .Nm
1270: implementations, at this time limited to GNU troff
1.2 kristaps 1271: .Pq Qq groff .
1272: The term
1273: .Qq historic groff
1.17 schwarze 1274: refers to groff version 1.15.
1.2 kristaps 1275: .Pp
1276: .Bl -dash -compact
1.10 kristaps 1277: .It
1.27 kristaps 1278: In mandoc, the
1279: .Sx \&EQ ,
1280: .Sx \&TE ,
1281: .Sx \&TS ,
1282: and
1283: .Sx \&T& ,
1284: macros are considered regular macros.
1285: In all other
1286: .Nm
1287: implementations, these are special macros that must be specified without
1288: spacing between the control character (which must be a period) and the
1289: macro name.
1290: .It
1.10 kristaps 1291: The
1292: .Cm nS
1.17 schwarze 1293: register is only compatible with OpenBSD's groff-1.15.
1.2 kristaps 1294: .It
1.17 schwarze 1295: Historic groff did not accept white-space before a custom
1296: .Ar end
1297: macro for the
1.2 kristaps 1298: .Sx \&ig
1.17 schwarze 1299: request.
1.4 kristaps 1300: .It
1301: The
1302: .Sx \&if
1303: and family would print funny white-spaces with historic groff when
1.17 schwarze 1304: using the next-line syntax.
1.2 kristaps 1305: .El
1.17 schwarze 1306: .Sh SEE ALSO
1307: .Xr mandoc 1 ,
1.27 kristaps 1308: .Xr eqn 7 ,
1.17 schwarze 1309: .Xr man 7 ,
1310: .Xr mandoc_char 7 ,
1.23 kristaps 1311: .Xr mdoc 7 ,
1312: .Xr tbl 7
1.17 schwarze 1313: .Rs
1314: .%A Joseph F. Ossanna
1315: .%A Brian W. Kernighan
1316: .%I AT&T Bell Laboratories
1317: .%T Troff User's Manual
1318: .%R Computing Science Technical Report
1319: .%N 54
1320: .%C Murray Hill, New Jersey
1321: .%D 1976 and 1992
1322: .%U http://www.kohala.com/start/troff/cstr54.ps
1323: .Re
1324: .Rs
1325: .%A Joseph F. Ossanna
1326: .%A Brian W. Kernighan
1327: .%A Gunnar Ritter
1328: .%T Heirloom Documentation Tools Nroff/Troff User's Manual
1329: .%D September 17, 2007
1330: .%U http://heirloom.sourceforge.net/doctools/troff.pdf
1331: .Re
1332: .Sh HISTORY
1.35 kristaps 1333: The RUNOFF typesetting system, whose input forms the basis for
1.17 schwarze 1334: .Nm ,
1.35 kristaps 1335: was written in MAD and FAP for the CTSS operating system by Jerome E.
1336: Saltzer in 1964.
1337: Doug McIlroy rewrote it in BCPL in 1969, renaming it
1338: .Nm .
1339: Dennis M. Ritchie rewrote McIlroy's
1.36 schwarze 1340: .Nm
1341: in PDP-11 assembly for
1.35 kristaps 1342: .At v1 ,
1343: Joseph F. Ossanna improved roff and renamed it nroff
1344: for
1345: .At v2 ,
1346: then ported nroff to C as troff, which Brian W. Kernighan released with
1347: .At v7 .
1348: In 1989, James Clarke re-implemented troff in C++, naming it groff.
1.1 kristaps 1349: .Sh AUTHORS
1.15 kristaps 1350: .An -nosplit
1.31 kristaps 1351: This
1.1 kristaps 1352: .Nm
1353: reference was written by
1.41 schwarze 1354: .An Kristaps Dzonsons Aq Mt kristaps@bsd.lv
1.15 kristaps 1355: and
1.41 schwarze 1356: .An Ingo Schwarze Aq Mt schwarze@openbsd.org .
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