mandoc_char.7

   1 .\" $Id: mandoc_char.7,v 1.79 2022/06/02 14:51:41 schwarze Exp $
   2 .\"
   3 .\" Copyright (c) 2003 Jason McIntyre <jmc@openbsd.org>
   4 .\" Copyright (c) 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
   5 .\" Copyright (c) 2011, 2013, 2015, 2017-2020, 2022
   6 .\"               Ingo Schwarze <schwarze@openbsd.org>
   7 .\"
   8 .\" Permission to use, copy, modify, and distribute this software for any
   9 .\" purpose with or without fee is hereby granted, provided that the above
  10 .\" copyright notice and this permission notice appear in all copies.
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  12 .\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  13 .\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  14 .\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  15 .\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  16 .\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  17 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  18 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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  20 .Dd $Mdocdate: June 2 2022 $
  21 .Dt MANDOC_CHAR 7
  22 .Os
  23 .Sh NAME
  24 .Nm mandoc_char
  25 .Nd mandoc special characters
  26 .Sh DESCRIPTION
  27 This page documents the
  28 .Xr roff 7
  29 escape sequences accepted by
  30 .Xr mandoc 1
  31 to represent special characters in
  32 .Xr mdoc 7
  33 and
  34 .Xr man 7
  35 documents.
  36 .Pp
  37 The rendering depends on the
  38 .Xr mandoc 1
  39 output mode; it can be inspected by calling
  40 .Xr man 1
  41 on the
  42 .Nm
  43 manual page with different
  44 .Fl T
  45 arguments.
  46 In ASCII output, the rendering of some characters may be hard
  47 to interpret for the reader.
  48 Many are rendered as descriptive strings like
  49 .Qq <integral> ,
  50 .Qq <degree> ,
  51 or
  52 .Qq <Gamma> ,
  53 which may look ugly, and many are replaced by similar ASCII characters.
  54 In particular, accented characters are usually shown without the accent.
  55 For that reason, try to avoid using any of the special characters
  56 documented here except those discussed in the
  57 .Sx DESCRIPTION ,
  58 unless they are essential for explaining the subject matter at hand,
  59 for example when documenting complicated mathematical functions.
  60 .Pp
  61 In particular, in English manual pages, do not use special-character
  62 escape sequences to represent national language characters in author
  63 names; instead, provide ASCII transcriptions of the names.
  64 .Ss Dashes and Hyphens
  65 In typography there are different types of dashes of various width:
  66 the hyphen (\(hy),
  67 the en-dash (\(en),
  68 the em-dash (\(em),
  69 and the mathematical minus sign (\(mi).
  70 .Pp
  71 Hyphens are used for adjectives;
  72 to separate the two parts of a compound word;
  73 or to separate a word across two successive lines of text.
  74 The hyphen does not need to be escaped:
  75 .Bd -unfilled -offset indent
  76 blue-eyed
  77 lorry-driver
  78 .Ed
  79 .Pp
  80 The en-dash is used to separate the two elements of a range,
  81 or can be used the same way as an em-dash.
  82 It should be written as
  83 .Sq \e(en :
  84 .Bd -unfilled -offset indent
  85 pp. 95\e(en97.
  86 Go away \e(en or else!
  87 .Ed
  88 .Pp
  89 The em-dash can be used to show an interruption
  90 or can be used the same way as colons, semi-colons, or parentheses.
  91 It should be written as
  92 .Sq \e(em :
  93 .Bd -unfilled -offset indent
  94 Three things \e(em apples, oranges, and bananas.
  95 This is not that \e(em rather, this is that.
  96 .Ed
  97 .Pp
  98 In
  99 .Xr roff 7
 100 documents, the minus sign is normally written as
 101 .Sq \e- .
 102 In manual pages, some style guides recommend to also use
 103 .Sq \e-
 104 if an ASCII 0x2d
 105 .Dq hyphen-minus
 106 output glyph that can be copied and pasted is desired in output modes
 107 supporting it, for example in
 108 .Fl T Cm utf8
 109 and
 110 .Fl T Cm html .
 111 But currently, no practically relevant manual page formatter requires
 112 that subtlety, so in manual pages, it is sufficient to write plain
 113 .Sq -
 114 to represent hyphen, minus, and hyphen-minus.
 115 .Pp
 116 If a word on a text input line contains a hyphen, a formatter may decide
 117 to insert an output line break after the hyphen if that helps filling
 118 the current output line, but the whole word would overflow the line.
 119 If it is important that the word is not broken across lines in this
 120 way, a zero-width space
 121 .Pq Sq \e&
 122 can be inserted before or after the hyphen.
 123 While
 124 .Xr mandoc 1
 125 never breaks the output line after hyphens adjacent to a zero-width
 126 space, after any of the other dash- or hyphen-like characters
 127 represented by escape sequences, or after hyphens inside words in
 128 macro arguments, other software may not respect these rules and may
 129 break the line even in such cases.
 130 .Pp
 131 Some
 132 .Xr roff 7
 133 implementations contains dictionaries allowing to break the line
 134 at syllable boundaries even inside words that contain no hyphens.
 135 Such automatic hyphenation is not supported by
 136 .Xr mandoc 1 ,
 137 which only breaks the line at whitespace, and inside words only
 138 after existing hyphens.
 139 .Ss Spaces
 140 To separate words in normal text, for indenting and alignment
 141 in literal context, and when none of the following special cases apply,
 142 just use the normal space character
 143 .Pq Sq \  .
 144 .Pp
 145 When filling text, output lines may be broken between words, i.e. at space
 146 characters.
 147 To prevent a line break between two particular words,
 148 use the unpaddable non-breaking space escape sequence
 149 .Pq Sq \e\ \&
 150 instead of the normal space character.
 151 For example, the input string
 152 .Dq number\e\ 1
 153 will be kept together as
 154 .Dq number\ 1
 155 on the same output line.
 156 .Pp
 157 On request and macro lines, the normal space character serves as an
 158 argument delimiter.
 159 To include whitespace into arguments, quoting is usually the best choice;
 160 see the MACRO SYNTAX section in
 161 .Xr roff 7 .
 162 In some cases, using the non-breaking space escape sequence
 163 .Pq Sq \e\ \&
 164 may be preferable.
 165 .Pp
 166 To escape macro names and to protect whitespace at the end
 167 of input lines, the zero-width space
 168 .Pq Sq \e&
 169 is often useful.
 170 For example, in
 171 .Xr mdoc 7 ,
 172 a normal space character can be displayed in single quotes in either
 173 of the following ways:
 174 .Pp
 175 .Dl .Sq \(dq \(dq
 176 .Dl .Sq \e \e&
 177 .Ss Quotes
 178 On request and macro lines, the double-quote character
 179 .Pq Sq \(dq
 180 is handled specially to allow quoting.
 181 One way to prevent this special handling is by using the
 182 .Sq \e(dq
 183 escape sequence.
 184 .Pp
 185 Note that on text lines, literal double-quote characters can be used
 186 verbatim.
 187 All other quote-like characters can be used verbatim as well,
 188 even on request and macro lines.
 189 .Ss Accents
 190 In output modes supporting such special output characters, for example
 191 .Fl T Cm pdf ,
 192 and sometimes less consistently in
 193 .Fl T Cm utf8 ,
 194 some
 195 .Xr roff 7
 196 formatters convert the following ASCII input characters to the
 197 following Unicode special output characters:
 198 .Bl -column x(ga U+2018 -offset indent
 199 .It \(ga Ta U+2018 Ta left single quotation mark
 200 .It \(aq Ta U+2019 Ta right single quotation mark
 201 .It \(ti Ta U+02DC Ta small tilde
 202 .It \(ha Ta U+02C6 Ta modifier letter circumflex
 203 .El
 204 .Pp
 205 In prose, this automatic substitution is often desirable;
 206 but when these characters have to be displayed as plain ASCII
 207 characters, for example in source code samples, they require
 208 escaping to render as follows:
 209 .Bl -column x(ga U+2018 -offset indent
 210 .It \e(ga Ta U+0060 Ta grave accent
 211 .It \e(aq Ta U+0027 Ta apostrophe
 212 .It \e(ti Ta U+007E Ta tilde
 213 .It \e(ha Ta U+005E Ta circumflex accent
 214 .El
 215 .Ss Periods
 216 The period
 217 .Pq Sq \&.
 218 is handled specially at the beginning of an input line,
 219 where it introduces a
 220 .Xr roff 7
 221 request or a macro, and when appearing alone as a macro argument in
 222 .Xr mdoc 7 .
 223 In such situations, prepend a zero-width space
 224 .Pq Sq \e&.\&
 225 to make it behave like normal text.
 226 .Pp
 227 Do not use the character pair
 228 .Sq \e.
 229 to escape a period because
 230 .Sq \e.
 231 is not a character escape sequence, does not prevent special handling
 232 of the period under normal circumstances, and is only intended to
 233 be used in the very special situation of defining a user-defined
 234 macro that, when called, defines another user-defined macro, which
 235 no manual page is ever supposed to do.
 236 .Ss Backslashes
 237 To include a literal backslash
 238 .Pq Sq \e
 239 into the output, use the
 240 .Pq Sq \ee
 241 escape sequence.
 242 .Pp
 243 Note that doubling it
 244 .Pq Sq \e\e
 245 is not the right way to output a backslash.
 246 Because
 247 .Xr mandoc 1
 248 does not implement full
 249 .Xr roff 7
 250 functionality, it may work with
 251 .Xr mandoc 1 ,
 252 but it may have weird effects on complete
 253 .Xr roff 7
 254 implementations.
 255 .Sh SPECIAL CHARACTERS
 256 Special characters are encoded as
 257 .Sq \eX
 258 .Pq for a one-character escape ,
 259 .Sq \e(XX
 260 .Pq two-character ,
 261 and
 262 .Sq \e[N]
 263 .Pq N-character .
 264 For details, see the
 265 .Em Special Characters
 266 subsection of the
 267 .Xr roff 7
 268 manual.
 269 .Pp
 270 Spaces, non-breaking unless stated otherwise:
 271 .Bl -column "Input" "Description" -offset indent -compact
 272 .It Em Input Ta Em Description
 273 .It Sq \e\ \& Ta unpaddable space
 274 .It \e\(ti   Ta paddable space
 275 .It \e0      Ta digit-width space
 276 .It \e|      Ta one-sixth \e(em narrow space, zero width in nroff mode
 277 .It \e^      Ta one-twelfth \e(em half-narrow space, zero width in nroff
 278 .It \e&      Ta zero-width space
 279 .It \e)      Ta zero-width space transparent to end-of-sentence detection
 280 .It \e%      Ta zero-width space allowing hyphenation
 281 .It \e:      Ta zero-width space allowing line break
 282 .El
 283 .Pp
 284 Lines:
 285 .Bl -column "Input" "Rendered" "Description" -offset indent -compact
 286 .It Em Input Ta Em Rendered Ta Em Description
 287 .It \e(ba    Ta \(ba        Ta bar
 288 .It \e(br    Ta \(br        Ta box rule
 289 .It \e(ul    Ta \(ul        Ta underscore
 290 .It \e(ru    Ta \(ru        Ta underscore (width 0.5m)
 291 .It \e(rn    Ta \(rn        Ta overline
 292 .It \e(bb    Ta \(bb        Ta broken bar
 293 .It \e(sl    Ta \(sl        Ta forward slash
 294 .It \e(rs    Ta \(rs        Ta backward slash
 295 .El
 296 .Pp
 297 Text markers:
 298 .Bl -column "Input" "Rendered" "Description" -offset indent -compact
 299 .It Em Input Ta Em Rendered Ta Em Description
 300 .It \e(ci    Ta \(ci        Ta circle
 301 .It \e(bu    Ta \(bu        Ta bullet
 302 .It \e(dd    Ta \(dd        Ta double dagger
 303 .It \e(dg    Ta \(dg        Ta dagger
 304 .It \e(lz    Ta \(lz        Ta lozenge
 305 .It \e(sq    Ta \(sq        Ta white square
 306 .It \e(ps    Ta \(ps        Ta paragraph
 307 .It \e(sc    Ta \(sc        Ta section
 308 .It \e(lh    Ta \(lh        Ta left hand
 309 .It \e(rh    Ta \(rh        Ta right hand
 310 .It \e(at    Ta \(at        Ta at
 311 .It \e(sh    Ta \(sh        Ta hash (pound)
 312 .It \e(CR    Ta \(CR        Ta carriage return
 313 .It \e(OK    Ta \(OK        Ta check mark
 314 .It \e(CL    Ta \(CL        Ta club suit
 315 .It \e(SP    Ta \(SP        Ta spade suit
 316 .It \e(HE    Ta \(HE        Ta heart suit
 317 .It \e(DI    Ta \(DI        Ta diamond suit
 318 .El
 319 .Pp
 320 Legal symbols:
 321 .Bl -column "Input" "Rendered" "Description" -offset indent -compact
 322 .It Em Input Ta Em Rendered Ta Em Description
 323 .It \e(co    Ta \(co        Ta copyright
 324 .It \e(rg    Ta \(rg        Ta registered
 325 .It \e(tm    Ta \(tm        Ta trademarked
 326 .El
 327 .Pp
 328 Punctuation:
 329 .Bl -column "Input" "Rendered" "Description" -offset indent -compact
 330 .It Em Input Ta Em Rendered Ta Em Description
 331 .It \e(em    Ta \(em        Ta em-dash
 332 .It \e(en    Ta \(en        Ta en-dash
 333 .It \e(hy    Ta \(hy        Ta hyphen
 334 .It \ee      Ta \e          Ta back-slash
 335 .It \e(r!    Ta \(r!        Ta upside-down exclamation
 336 .It \e(r?    Ta \(r?        Ta upside-down question
 337 .El
 338 .Pp
 339 Quotes:
 340 .Bl -column "Input" "Rendered" "Description" -offset indent -compact
 341 .It Em Input Ta Em Rendered Ta Em Description
 342 .It \e(Bq    Ta \(Bq        Ta right low double-quote
 343 .It \e(bq    Ta \(bq        Ta right low single-quote
 344 .It \e(lq    Ta \(lq        Ta left double-quote
 345 .It \e(rq    Ta \(rq        Ta right double-quote
 346 .It \e(oq    Ta \(oq        Ta left single-quote
 347 .It \e(cq    Ta \(cq        Ta right single-quote
 348 .It \e(aq    Ta \(aq        Ta apostrophe quote (ASCII character)
 349 .It \e(dq    Ta \(dq        Ta double quote (ASCII character)
 350 .It \e(Fo    Ta \(Fo        Ta left guillemet
 351 .It \e(Fc    Ta \(Fc        Ta right guillemet
 352 .It \e(fo    Ta \(fo        Ta left single guillemet
 353 .It \e(fc    Ta \(fc        Ta right single guillemet
 354 .El
 355 .Pp
 356 Brackets:
 357 .Bl -column "xxbracketrightbtx" Rendered Description -offset indent -compact
 358 .It Em Input Ta Em Rendered Ta Em Description
 359 .It \e(lB    Ta \(lB        Ta left bracket
 360 .It \e(rB    Ta \(rB        Ta right bracket
 361 .It \e(lC    Ta \(lC        Ta left brace
 362 .It \e(rC    Ta \(rC        Ta right brace
 363 .It \e(la    Ta \(la        Ta left angle
 364 .It \e(ra    Ta \(ra        Ta right angle
 365 .It \e(bv    Ta \(bv        Ta brace extension (special font)
 366 .It \e[braceex] Ta \[braceex] Ta brace extension
 367 .It \e[bracketlefttp] Ta \[bracketlefttp] Ta top-left hooked bracket
 368 .It \e[bracketleftbt] Ta \[bracketleftbt] Ta bottom-left hooked bracket
 369 .It \e[bracketleftex] Ta \[bracketleftex] Ta left hooked bracket extension
 370 .It \e[bracketrighttp] Ta \[bracketrighttp] Ta top-right hooked bracket
 371 .It \e[bracketrightbt] Ta \[bracketrightbt] Ta bottom-right hooked bracket
 372 .It \e[bracketrightex] Ta \[bracketrightex] Ta right hooked bracket extension
 373 .It \e(lt    Ta \(lt        Ta top-left hooked brace
 374 .It \e[bracelefttp] Ta \[bracelefttp] Ta top-left hooked brace
 375 .It \e(lk    Ta \(lk        Ta mid-left hooked brace
 376 .It \e[braceleftmid] Ta \[braceleftmid] Ta mid-left hooked brace
 377 .It \e(lb    Ta \(lb        Ta bottom-left hooked brace
 378 .It \e[braceleftbt] Ta \[braceleftbt] Ta bottom-left hooked brace
 379 .It \e[braceleftex] Ta \[braceleftex] Ta left hooked brace extension
 380 .It \e(rt    Ta \(rt        Ta top-left hooked brace
 381 .It \e[bracerighttp] Ta \[bracerighttp] Ta top-right hooked brace
 382 .It \e(rk    Ta \(rk        Ta mid-right hooked brace
 383 .It \e[bracerightmid] Ta \[bracerightmid] Ta mid-right hooked brace
 384 .It \e(rb    Ta \(rb        Ta bottom-right hooked brace
 385 .It \e[bracerightbt] Ta \[bracerightbt] Ta bottom-right hooked brace
 386 .It \e[bracerightex] Ta \[bracerightex] Ta right hooked brace extension
 387 .It \e[parenlefttp] Ta \[parenlefttp] Ta top-left hooked parenthesis
 388 .It \e[parenleftbt] Ta \[parenleftbt] Ta bottom-left hooked parenthesis
 389 .It \e[parenleftex] Ta \[parenleftex] Ta left hooked parenthesis extension
 390 .It \e[parenrighttp] Ta \[parenrighttp] Ta top-right hooked parenthesis
 391 .It \e[parenrightbt] Ta \[parenrightbt] Ta bottom-right hooked parenthesis
 392 .It \e[parenrightex] Ta \[parenrightex] Ta right hooked parenthesis extension
 393 .El
 394 .Pp
 395 Arrows:
 396 .Bl -column "Input" "Rendered" "Description" -offset indent -compact
 397 .It Em Input Ta Em Rendered Ta Em Description
 398 .It \e(<-    Ta \(<-        Ta left arrow
 399 .It \e(->    Ta \(->        Ta right arrow
 400 .It \e(<>    Ta \(<>        Ta left-right arrow
 401 .It \e(da    Ta \(da        Ta down arrow
 402 .It \e(ua    Ta \(ua        Ta up arrow
 403 .It \e(va    Ta \(va        Ta up-down arrow
 404 .It \e(lA    Ta \(lA        Ta left double-arrow
 405 .It \e(rA    Ta \(rA        Ta right double-arrow
 406 .It \e(hA    Ta \(hA        Ta left-right double-arrow
 407 .It \e(uA    Ta \(uA        Ta up double-arrow
 408 .It \e(dA    Ta \(dA        Ta down double-arrow
 409 .It \e(vA    Ta \(vA        Ta up-down double-arrow
 410 .It \e(an    Ta \(an        Ta horizontal arrow extension
 411 .El
 412 .Pp
 413 Logical:
 414 .Bl -column "Input" "Rendered" "Description" -offset indent -compact
 415 .It Em Input Ta Em Rendered Ta Em Description
 416 .It \e(AN    Ta \(AN        Ta logical and
 417 .It \e(OR    Ta \(OR        Ta logical or
 418 .It \e[tno]  Ta \[tno]      Ta logical not (text font)
 419 .It \e(no    Ta \(no        Ta logical not (special font)
 420 .It \e(te    Ta \(te        Ta existential quantifier
 421 .It \e(fa    Ta \(fa        Ta universal quantifier
 422 .It \e(st    Ta \(st        Ta such that
 423 .It \e(tf    Ta \(tf        Ta therefore
 424 .It \e(3d    Ta \(3d        Ta therefore
 425 .It \e(or    Ta \(or        Ta bitwise or
 426 .El
 427 .Pp
 428 Mathematical:
 429 .Bl -column "xxcoproductxx" "Rendered" "Description" -offset indent -compact
 430 .It Em Input Ta Em Rendered Ta Em Description
 431 .It \e-      Ta \-          Ta minus (text font)
 432 .It \e(mi    Ta \(mi        Ta minus (special font)
 433 .It +        Ta +           Ta plus (text font)
 434 .It \e(pl    Ta \(pl        Ta plus (special font)
 435 .It \e(-+    Ta \(-+        Ta minus-plus
 436 .It \e[t+-]  Ta \[t+-]      Ta plus-minus (text font)
 437 .It \e(+-    Ta \(+-        Ta plus-minus (special font)
 438 .It \e(pc    Ta \(pc        Ta center-dot
 439 .It \e[tmu]  Ta \[tmu]      Ta multiply (text font)
 440 .It \e(mu    Ta \(mu        Ta multiply (special font)
 441 .It \e(c*    Ta \(c*        Ta circle-multiply
 442 .It \e(c+    Ta \(c+        Ta circle-plus
 443 .It \e[tdi]  Ta \[tdi]      Ta divide (text font)
 444 .It \e(di    Ta \(di        Ta divide (special font)
 445 .It \e(f/    Ta \(f/        Ta fraction
 446 .It \e(**    Ta \(**        Ta asterisk
 447 .It \e(<=    Ta \(<=        Ta less-than-equal
 448 .It \e(>=    Ta \(>=        Ta greater-than-equal
 449 .It \e(<<    Ta \(<<        Ta much less
 450 .It \e(>>    Ta \(>>        Ta much greater
 451 .It \e(eq    Ta \(eq        Ta equal
 452 .It \e(!=    Ta \(!=        Ta not equal
 453 .It \e(==    Ta \(==        Ta equivalent
 454 .It \e(ne    Ta \(ne        Ta not equivalent
 455 .It \e(ap    Ta \(ap        Ta tilde operator
 456 .It \e(|=    Ta \(|=        Ta asymptotically equal
 457 .It \e(=\(ti Ta \(=~        Ta approximately equal
 458 .It \e(\(ti\(ti Ta \(~~        Ta almost equal
 459 .It \e(\(ti= Ta \(~=        Ta almost equal
 460 .It \e(pt    Ta \(pt        Ta proportionate
 461 .It \e(es    Ta \(es        Ta empty set
 462 .It \e(mo    Ta \(mo        Ta element
 463 .It \e(nm    Ta \(nm        Ta not element
 464 .It \e(sb    Ta \(sb        Ta proper subset
 465 .It \e(nb    Ta \(nb        Ta not subset
 466 .It \e(sp    Ta \(sp        Ta proper superset
 467 .It \e(nc    Ta \(nc        Ta not superset
 468 .It \e(ib    Ta \(ib        Ta reflexive subset
 469 .It \e(ip    Ta \(ip        Ta reflexive superset
 470 .It \e(ca    Ta \(ca        Ta intersection
 471 .It \e(cu    Ta \(cu        Ta union
 472 .It \e(/_    Ta \(/_        Ta angle
 473 .It \e(pp    Ta \(pp        Ta perpendicular
 474 .It \e(is    Ta \(is        Ta integral
 475 .It \e[integral] Ta \[integral] Ta integral
 476 .It \e[sum]    Ta \[sum]   Ta summation
 477 .It \e[product] Ta \[product] Ta product
 478 .It \e[coproduct] Ta \[coproduct] Ta coproduct
 479 .It \e(gr    Ta \(gr        Ta gradient
 480 .It \e(sr    Ta \(sr        Ta square root
 481 .It \e[sqrt] Ta \[sqrt]     Ta square root
 482 .It \e(lc    Ta \(lc        Ta left-ceiling
 483 .It \e(rc    Ta \(rc        Ta right-ceiling
 484 .It \e(lf    Ta \(lf        Ta left-floor
 485 .It \e(rf    Ta \(rf        Ta right-floor
 486 .It \e(if    Ta \(if        Ta infinity
 487 .It \e(Ah    Ta \(Ah        Ta aleph
 488 .It \e(Im    Ta \(Im        Ta imaginary
 489 .It \e(Re    Ta \(Re        Ta real
 490 .It \e(wp    Ta \(wp        Ta Weierstrass p
 491 .It \e(pd    Ta \(pd        Ta partial differential
 492 .It \e(-h    Ta \(-h        Ta Planck constant over 2\(*p
 493 .It \e[hbar] Ta \[hbar]     Ta Planck constant over 2\(*p
 494 .It \e(12    Ta \(12        Ta one-half
 495 .It \e(14    Ta \(14        Ta one-fourth
 496 .It \e(34    Ta \(34        Ta three-fourths
 497 .It \e(18    Ta \(18        Ta one-eighth
 498 .It \e(38    Ta \(38        Ta three-eighths
 499 .It \e(58    Ta \(58        Ta five-eighths
 500 .It \e(78    Ta \(78        Ta seven-eighths
 501 .It \e(S1    Ta \(S1        Ta superscript 1
 502 .It \e(S2    Ta \(S2        Ta superscript 2
 503 .It \e(S3    Ta \(S3        Ta superscript 3
 504 .El
 505 .Pp
 506 Ligatures:
 507 .Bl -column "Input" "Rendered" "Description" -offset indent -compact
 508 .It Em Input Ta Em Rendered Ta Em Description
 509 .It \e(ff    Ta \(ff        Ta ff ligature
 510 .It \e(fi    Ta \(fi        Ta fi ligature
 511 .It \e(fl    Ta \(fl        Ta fl ligature
 512 .It \e(Fi    Ta \(Fi        Ta ffi ligature
 513 .It \e(Fl    Ta \(Fl        Ta ffl ligature
 514 .It \e(AE    Ta \(AE        Ta AE
 515 .It \e(ae    Ta \(ae        Ta ae
 516 .It \e(OE    Ta \(OE        Ta OE
 517 .It \e(oe    Ta \(oe        Ta oe
 518 .It \e(ss    Ta \(ss        Ta German eszett
 519 .It \e(IJ    Ta \(IJ        Ta IJ ligature
 520 .It \e(ij    Ta \(ij        Ta ij ligature
 521 .El
 522 .Pp
 523 Accents:
 524 .Bl -column "Input" "Rendered" "Description" -offset indent -compact
 525 .It Em Input Ta Em Rendered Ta Em Description
 526 .It \e(a"    Ta \(a"        Ta Hungarian umlaut
 527 .It \e(a-    Ta \(a-        Ta macron
 528 .It \e(a.    Ta \(a.        Ta dotted
 529 .It \e(a^    Ta \(a^        Ta circumflex
 530 .It \e(aa    Ta \(aa        Ta acute
 531 .It \e\(aq   Ta \'          Ta acute
 532 .It \e(ga    Ta \(ga        Ta grave
 533 .It \e\(ga   Ta \`          Ta grave
 534 .It \e(ab    Ta \(ab        Ta breve
 535 .It \e(ac    Ta \(ac        Ta cedilla
 536 .It \e(ad    Ta \(ad        Ta dieresis
 537 .It \e(ah    Ta \(ah        Ta caron
 538 .It \e(ao    Ta \(ao        Ta ring
 539 .It \e(a\(ti Ta \(a~        Ta tilde
 540 .It \e(ho    Ta \(ho        Ta ogonek
 541 .It \e(ha    Ta \(ha        Ta hat (ASCII character)
 542 .It \e(ti    Ta \(ti        Ta tilde (ASCII character)
 543 .El
 544 .Pp
 545 Accented letters:
 546 .Bl -column "Input" "Rendered" "Description" -offset indent -compact
 547 .It Em Input Ta Em Rendered Ta Em Description
 548 .It \e(\(aqA Ta \('A        Ta acute A
 549 .It \e(\(aqE Ta \('E        Ta acute E
 550 .It \e(\(aqI Ta \('I        Ta acute I
 551 .It \e(\(aqO Ta \('O        Ta acute O
 552 .It \e(\(aqU Ta \('U        Ta acute U
 553 .It \e(\(aqY Ta \('Y        Ta acute Y
 554 .It \e(\(aqa Ta \('a        Ta acute a
 555 .It \e(\(aqe Ta \('e        Ta acute e
 556 .It \e(\(aqi Ta \('i        Ta acute i
 557 .It \e(\(aqo Ta \('o        Ta acute o
 558 .It \e(\(aqu Ta \('u        Ta acute u
 559 .It \e(\(aqy Ta \('y        Ta acute y
 560 .It \e(\(gaA Ta \(`A        Ta grave A
 561 .It \e(\(gaE Ta \(`E        Ta grave E
 562 .It \e(\(gaI Ta \(`I        Ta grave I
 563 .It \e(\(gaO Ta \(`O        Ta grave O
 564 .It \e(\(gaU Ta \(`U        Ta grave U
 565 .It \e(\(gaa Ta \(`a        Ta grave a
 566 .It \e(\(gae Ta \(`e        Ta grave e
 567 .It \e(\(gai Ta \(`i        Ta grave i
 568 .It \e(\(gao Ta \(`i        Ta grave o
 569 .It \e(\(gau Ta \(`u        Ta grave u
 570 .It \e(\(tiA Ta \(~A        Ta tilde A
 571 .It \e(\(tiN Ta \(~N        Ta tilde N
 572 .It \e(\(tiO Ta \(~O        Ta tilde O
 573 .It \e(\(tia Ta \(~a        Ta tilde a
 574 .It \e(\(tin Ta \(~n        Ta tilde n
 575 .It \e(\(tio Ta \(~o        Ta tilde o
 576 .It \e(:A    Ta \(:A        Ta dieresis A
 577 .It \e(:E    Ta \(:E        Ta dieresis E
 578 .It \e(:I    Ta \(:I        Ta dieresis I
 579 .It \e(:O    Ta \(:O        Ta dieresis O
 580 .It \e(:U    Ta \(:U        Ta dieresis U
 581 .It \e(:a    Ta \(:a        Ta dieresis a
 582 .It \e(:e    Ta \(:e        Ta dieresis e
 583 .It \e(:i    Ta \(:i        Ta dieresis i
 584 .It \e(:o    Ta \(:o        Ta dieresis o
 585 .It \e(:u    Ta \(:u        Ta dieresis u
 586 .It \e(:y    Ta \(:y        Ta dieresis y
 587 .It \e(^A    Ta \(^A        Ta circumflex A
 588 .It \e(^E    Ta \(^E        Ta circumflex E
 589 .It \e(^I    Ta \(^I        Ta circumflex I
 590 .It \e(^O    Ta \(^O        Ta circumflex O
 591 .It \e(^U    Ta \(^U        Ta circumflex U
 592 .It \e(^a    Ta \(^a        Ta circumflex a
 593 .It \e(^e    Ta \(^e        Ta circumflex e
 594 .It \e(^i    Ta \(^i        Ta circumflex i
 595 .It \e(^o    Ta \(^o        Ta circumflex o
 596 .It \e(^u    Ta \(^u        Ta circumflex u
 597 .It \e(,C    Ta \(,C        Ta cedilla C
 598 .It \e(,c    Ta \(,c        Ta cedilla c
 599 .It \e(/L    Ta \(/L        Ta stroke L
 600 .It \e(/l    Ta \(/l        Ta stroke l
 601 .It \e(/O    Ta \(/O        Ta stroke O
 602 .It \e(/o    Ta \(/o        Ta stroke o
 603 .It \e(oA    Ta \(oA        Ta ring A
 604 .It \e(oa    Ta \(oa        Ta ring a
 605 .El
 606 .Pp
 607 Special letters:
 608 .Bl -column "Input" "Rendered" "Description" -offset indent -compact
 609 .It Em Input Ta Em Rendered Ta Em Description
 610 .It \e(-D    Ta \(-D        Ta Eth
 611 .It \e(Sd    Ta \(Sd        Ta eth
 612 .It \e(TP    Ta \(TP        Ta Thorn
 613 .It \e(Tp    Ta \(Tp        Ta thorn
 614 .It \e(.i    Ta \(.i        Ta dotless i
 615 .It \e(.j    Ta \(.j        Ta dotless j
 616 .El
 617 .Pp
 618 Currency:
 619 .Bl -column "Input" "Rendered" "Description" -offset indent -compact
 620 .It Em Input Ta Em Rendered Ta Em Description
 621 .It \e(Do    Ta \(Do        Ta dollar
 622 .It \e(ct    Ta \(ct        Ta cent
 623 .It \e(Eu    Ta \(Eu        Ta Euro symbol
 624 .It \e(eu    Ta \(eu        Ta Euro symbol
 625 .It \e(Ye    Ta \(Ye        Ta yen
 626 .It \e(Po    Ta \(Po        Ta pound
 627 .It \e(Cs    Ta \(Cs        Ta Scandinavian
 628 .It \e(Fn    Ta \(Fn        Ta florin
 629 .El
 630 .Pp
 631 Units:
 632 .Bl -column "Input" "Rendered" "Description" -offset indent -compact
 633 .It Em Input Ta Em Rendered Ta Em Description
 634 .It \e(de    Ta \(de        Ta degree
 635 .It \e(%0    Ta \(%0        Ta per-thousand
 636 .It \e(fm    Ta \(fm        Ta minute
 637 .It \e(sd    Ta \(sd        Ta second
 638 .It \e(mc    Ta \(mc        Ta micro
 639 .It \e(Of    Ta \(Of        Ta Spanish female ordinal
 640 .It \e(Om    Ta \(Om        Ta Spanish masculine ordinal
 641 .El
 642 .Pp
 643 Greek letters:
 644 .Bl -column "Input" "Rendered" "Description" -offset indent -compact
 645 .It Em Input Ta Em Rendered Ta Em Description
 646 .It \e(*A    Ta \(*A        Ta Alpha
 647 .It \e(*B    Ta \(*B        Ta Beta
 648 .It \e(*G    Ta \(*G        Ta Gamma
 649 .It \e(*D    Ta \(*D        Ta Delta
 650 .It \e(*E    Ta \(*E        Ta Epsilon
 651 .It \e(*Z    Ta \(*Z        Ta Zeta
 652 .It \e(*Y    Ta \(*Y        Ta Eta
 653 .It \e(*H    Ta \(*H        Ta Theta
 654 .It \e(*I    Ta \(*I        Ta Iota
 655 .It \e(*K    Ta \(*K        Ta Kappa
 656 .It \e(*L    Ta \(*L        Ta Lambda
 657 .It \e(*M    Ta \(*M        Ta Mu
 658 .It \e(*N    Ta \(*N        Ta Nu
 659 .It \e(*C    Ta \(*C        Ta Xi
 660 .It \e(*O    Ta \(*O        Ta Omicron
 661 .It \e(*P    Ta \(*P        Ta Pi
 662 .It \e(*R    Ta \(*R        Ta Rho
 663 .It \e(*S    Ta \(*S        Ta Sigma
 664 .It \e(*T    Ta \(*T        Ta Tau
 665 .It \e(*U    Ta \(*U        Ta Upsilon
 666 .It \e(*F    Ta \(*F        Ta Phi
 667 .It \e(*X    Ta \(*X        Ta Chi
 668 .It \e(*Q    Ta \(*Q        Ta Psi
 669 .It \e(*W    Ta \(*W        Ta Omega
 670 .It \e(*a    Ta \(*a        Ta alpha
 671 .It \e(*b    Ta \(*b        Ta beta
 672 .It \e(*g    Ta \(*g        Ta gamma
 673 .It \e(*d    Ta \(*d        Ta delta
 674 .It \e(*e    Ta \(*e        Ta epsilon
 675 .It \e(*z    Ta \(*z        Ta zeta
 676 .It \e(*y    Ta \(*y        Ta eta
 677 .It \e(*h    Ta \(*h        Ta theta
 678 .It \e(*i    Ta \(*i        Ta iota
 679 .It \e(*k    Ta \(*k        Ta kappa
 680 .It \e(*l    Ta \(*l        Ta lambda
 681 .It \e(*m    Ta \(*m        Ta mu
 682 .It \e(*n    Ta \(*n        Ta nu
 683 .It \e(*c    Ta \(*c        Ta xi
 684 .It \e(*o    Ta \(*o        Ta omicron
 685 .It \e(*p    Ta \(*p        Ta pi
 686 .It \e(*r    Ta \(*r        Ta rho
 687 .It \e(*s    Ta \(*s        Ta sigma
 688 .It \e(*t    Ta \(*t        Ta tau
 689 .It \e(*u    Ta \(*u        Ta upsilon
 690 .It \e(*f    Ta \(*f        Ta phi
 691 .It \e(*x    Ta \(*x        Ta chi
 692 .It \e(*q    Ta \(*q        Ta psi
 693 .It \e(*w    Ta \(*w        Ta omega
 694 .It \e(+h    Ta \(+h        Ta theta variant
 695 .It \e(+f    Ta \(+f        Ta phi variant
 696 .It \e(+p    Ta \(+p        Ta pi variant
 697 .It \e(+e    Ta \(+e        Ta epsilon variant
 698 .It \e(ts    Ta \(ts        Ta sigma terminal
 699 .El
 700 .Sh PREDEFINED STRINGS
 701 Predefined strings are inherited from the macro packages of historical
 702 troff implementations.
 703 They are
 704 .Em not recommended
 705 for use, as they differ across implementations.
 706 Manuals using these predefined strings are almost certainly not
 707 portable.
 708 .Pp
 709 Their syntax is similar to special characters, using
 710 .Sq \e*X
 711 .Pq for a one-character escape ,
 712 .Sq \e*(XX
 713 .Pq two-character ,
 714 and
 715 .Sq \e*[N]
 716 .Pq N-character .
 717 .Bl -column "Input" "Rendered" "Description" -offset indent
 718 .It Em Input Ta Em Rendered Ta Em Description
 719 .It \e*(Ba   Ta \*(Ba       Ta vertical bar
 720 .It \e*(Ne   Ta \*(Ne       Ta not equal
 721 .It \e*(Ge   Ta \*(Ge       Ta greater-than-equal
 722 .It \e*(Le   Ta \*(Le       Ta less-than-equal
 723 .It \e*(Gt   Ta \*(Gt       Ta greater-than
 724 .It \e*(Lt   Ta \*(Lt       Ta less-than
 725 .It \e*(Pm   Ta \*(Pm       Ta plus-minus
 726 .It \e*(If   Ta \*(If       Ta infinity
 727 .It \e*(Pi   Ta \*(Pi       Ta pi
 728 .It \e*(Na   Ta \*(Na       Ta NaN
 729 .It \e*(Am   Ta \*(Am       Ta ampersand
 730 .It \e*R     Ta \*R         Ta restricted mark
 731 .It \e*(Tm   Ta \*(Tm       Ta trade mark
 732 .It \e*q     Ta \*q         Ta double-quote
 733 .It \e*(Rq   Ta \*(Rq       Ta right-double-quote
 734 .It \e*(Lq   Ta \*(Lq       Ta left-double-quote
 735 .It \e*(lp   Ta \*(lp       Ta right-parenthesis
 736 .It \e*(rp   Ta \*(rp       Ta left-parenthesis
 737 .It \e*(lq   Ta \*(lq       Ta left double-quote
 738 .It \e*(rq   Ta \*(rq       Ta right double-quote
 739 .It \e*(ua   Ta \*(ua       Ta up arrow
 740 .It \e*(va   Ta \*(va       Ta up-down arrow
 741 .It \e*(<=   Ta \*(<=       Ta less-than-equal
 742 .It \e*(>=   Ta \*(>=       Ta greater-than-equal
 743 .It \e*(aa   Ta \*(aa       Ta acute
 744 .It \e*(ga   Ta \*(ga       Ta grave
 745 .It \e*(Px   Ta \*(Px       Ta POSIX standard name
 746 .It \e*(Ai   Ta \*(Ai       Ta ANSI standard name
 747 .El
 748 .Sh UNICODE CHARACTERS
 749 The escape sequences
 750 .Pp
 751 .Dl \e[uXXXX] and \eC\(aquXXXX\(aq
 752 .Pp
 753 are interpreted as Unicode codepoints.
 754 The codepoint must be in the range above U+0080 and less than U+10FFFF.
 755 For compatibility, the hexadecimal digits
 756 .Sq A
 757 to
 758 .Sq F
 759 must be given as uppercase characters,
 760 and points must be zero-padded to four characters; if
 761 greater than four characters, no zero padding is allowed.
 762 Unicode surrogates are not allowed.
 763 .Sh NUMBERED CHARACTERS
 764 For backward compatibility with existing manuals,
 765 .Xr mandoc 1
 766 also supports the
 767 .Pp
 768 .Dl \eN\(aq Ns Ar number Ns \(aq and \e[ Ns Cm char Ns Ar number ]
 769 .Pp
 770 escape sequences, inserting the character
 771 .Ar number
 772 from the current character set into the output.
 773 Of course, this is inherently non-portable and is already marked
 774 as deprecated in the Heirloom roff manual;
 775 on top of that, the second form is a GNU extension.
 776 For example, do not use \eN\(aq34\(aq or \e[char34], use \e(dq,
 777 or even the plain
 778 .Sq \(dq
 779 character where possible.
 780 .Sh COMPATIBILITY
 781 This section documents compatibility between mandoc and other
 782 troff implementations, at this time limited to GNU troff
 783 .Pq Qq groff .
 784 .Pp
 785 .Bl -dash -compact
 786 .It
 787 The \eN\(aq\(aq escape sequence is limited to printable characters; in
 788 groff, it accepts arbitrary character numbers.
 789 .It
 790 In
 791 .Fl T Ns Cm ascii ,
 792 the
 793 \e(ss, \e(nm, \e(nb, \e(nc, \e(ib, \e(ip, \e(pp, \e[sum], \e[product],
 794 \e[coproduct], \e(gr, \e(-h, and \e(a. special characters render
 795 differently between mandoc and groff.
 796 .It
 797 In
 798 .Fl T Ns Cm html ,
 799 the \e(\(ti=, \e(nb, and \e(nc special characters render differently
 800 between mandoc and groff.
 801 .It
 802 The
 803 .Fl T Ns Cm ps
 804 and
 805 .Fl T Ns Cm pdf
 806 modes format like
 807 .Fl T Ns Cm ascii
 808 instead of rendering glyphs as in groff.
 809 .It
 810 The \e[radicalex], \e[sqrtex], and \e(ru special characters have been omitted
 811 from mandoc either because they are poorly documented or they have no
 812 known representation.
 813 .El
 814 .Sh SEE ALSO
 815 .Xr mandoc 1 ,
 816 .Xr man 7 ,
 817 .Xr mdoc 7 ,
 818 .Xr roff 7
 819 .Sh AUTHORS
 820 The
 821 .Nm
 822 manual page was written by
 823 .An Kristaps Dzonsons Aq Mt kristaps@bsd.lv .
 824 .Sh CAVEATS
 825 The predefined string
 826 .Sq \e*(Ba
 827 mimics the behaviour of the
 828 .Sq \&|
 829 character in
 830 .Xr mdoc 7 ;
 831 thus, if you wish to render a vertical bar with no side effects, use
 832 the
 833 .Sq \e(ba
 834 escape.