1.\" $Id: roff.7,v 1.37 2011/12/11 00:38:11 schwarze Exp $ 2.\" 3.\" Copyright (c) 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv> 4.\" Copyright (c) 2010, 2011 Ingo Schwarze <schwarze@openbsd.org> 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. 17.\" 18.Dd $Mdocdate: December 11 2011 $ 19.Dt ROFF 7 20.Os 21.Sh NAME 22.Nm roff 23.Nd roff language reference for mandoc 24.Sh DESCRIPTION 25The 26.Nm roff 27language is a general purpose text formatting language. 28Since traditional implementations of the 29.Xr mdoc 7 30and 31.Xr man 7 32manual formatting languages are based on it, 33many real-world manuals use small numbers of 34.Nm 35requests intermixed with their 36.Xr mdoc 7 37or 38.Xr man 7 39code. 40To properly format such manuals, the 41.Xr mandoc 1 42utility supports a tiny subset of 43.Nm 44requests. 45Only these requests supported by 46.Xr mandoc 1 47are documented in the present manual, 48together with the basic language syntax shared by 49.Nm , 50.Xr mdoc 7 , 51and 52.Xr man 7 . 53For complete 54.Nm 55manuals, consult the 56.Sx SEE ALSO 57section. 58.Pp 59Input lines beginning with the control character 60.Sq \&. 61are parsed for requests and macros. 62Such lines are called 63.Dq request lines 64or 65.Dq macro lines , 66respectively. 67Requests change the processing state and manipulate the formatting; 68some macros also define the document structure and produce formatted 69output. 70The single quote 71.Pq Qq \(aq 72is accepted as an alternative control character, 73treated by 74.Xr mandoc 1 75just like 76.Ql \&. 77.Pp 78Lines not beginning with control characters are called 79.Dq text lines . 80They provide free-form text to be printed; the formatting of the text 81depends on the respective processing context. 82.Sh LANGUAGE SYNTAX 83.Nm 84documents may contain only graphable 7-bit ASCII characters, the space 85character, and, in certain circumstances, the tab character. 86The back-space character 87.Sq \e 88indicates the start of an escape sequence for 89.Sx Comments , 90.Sx Special Characters , 91.Sx Predefined Strings , 92and 93user-defined strings defined using the 94.Sx ds 95request. 96.Ss Comments 97Text following an escaped double-quote 98.Sq \e\(dq , 99whether in a request, macro, or text line, is ignored to the end of the line. 100A request line beginning with a control character and comment escape 101.Sq \&.\e\(dq 102is also ignored. 103Furthermore, request lines with only a control character and optional 104trailing whitespace are stripped from input. 105.Pp 106Examples: 107.Bd -literal -offset indent -compact 108\&.\e\(dq This is a comment line. 109\&.\e\(dq The next line is ignored: 110\&. 111\&.Sh EXAMPLES \e\(dq This is a comment, too. 112\&example text \e\(dq And so is this. 113.Ed 114.Ss Special Characters 115Special characters are used to encode special glyphs and are rendered 116differently across output media. 117They may occur in request, macro, and text lines. 118Sequences begin with the escape character 119.Sq \e 120followed by either an open-parenthesis 121.Sq \&( 122for two-character sequences; an open-bracket 123.Sq \&[ 124for n-character sequences (terminated at a close-bracket 125.Sq \&] ) ; 126or a single one character sequence. 127.Pp 128Examples: 129.Bl -tag -width Ds -offset indent -compact 130.It Li \e(em 131Two-letter em dash escape. 132.It Li \ee 133One-letter backslash escape. 134.El 135.Pp 136See 137.Xr mandoc_char 7 138for a complete list. 139.Ss Text Decoration 140Terms may be text-decorated using the 141.Sq \ef 142escape followed by an indicator: B (bold), I (italic), R (regular), or P 143(revert to previous mode). 144A numerical representation 3, 2, or 1 (bold, italic, and regular, 145respectively) may be used instead. 146The indicator or numerical representative may be preceded by C 147(constant-width), which is ignored. 148.Pp 149Examples: 150.Bl -tag -width Ds -offset indent -compact 151.It Li \efBbold\efR 152Write in bold, then switch to regular font mode. 153.It Li \efIitalic\efP 154Write in italic, then return to previous font mode. 155.El 156.Pp 157Text decoration is 158.Em not 159recommended for 160.Xr mdoc 7 , 161which encourages semantic annotation. 162.Ss Predefined Strings 163Predefined strings, like 164.Sx Special Characters , 165mark special output glyphs. 166Predefined strings are escaped with the slash-asterisk, 167.Sq \e* : 168single-character 169.Sq \e*X , 170two-character 171.Sq \e*(XX , 172and N-character 173.Sq \e*[N] . 174.Pp 175Examples: 176.Bl -tag -width Ds -offset indent -compact 177.It Li \e*(Am 178Two-letter ampersand predefined string. 179.It Li \e*q 180One-letter double-quote predefined string. 181.El 182.Pp 183Predefined strings are not recommended for use, 184as they differ across implementations. 185Those supported by 186.Xr mandoc 1 187are listed in 188.Xr mandoc_char 7 . 189Manuals using these predefined strings are almost certainly not portable. 190.Ss Whitespace 191Whitespace consists of the space character. 192In text lines, whitespace is preserved within a line. 193In request and macro lines, whitespace delimits arguments and is discarded. 194.Pp 195Unescaped trailing spaces are stripped from text line input unless in a 196literal context. 197In general, trailing whitespace on any input line is discouraged for 198reasons of portability. 199In the rare case that a blank character is needed at the end of an 200input line, it may be forced by 201.Sq \e\ \e& . 202.Pp 203Literal space characters can be produced in the output 204using escape sequences. 205In macro lines, they can also be included in arguments using quotation; see 206.Sx MACRO SYNTAX 207for details. 208.Pp 209Blank text lines, which may include whitespace, are only permitted 210within literal contexts. 211If the first character of a text line is a space, that line is printed 212with a leading newline. 213.Ss Scaling Widths 214Many requests and macros support scaled widths for their arguments. 215The syntax for a scaled width is 216.Sq Li [+-]?[0-9]*.[0-9]*[:unit:] , 217where a decimal must be preceded or followed by at least one digit. 218Negative numbers, while accepted, are truncated to zero. 219.Pp 220The following scaling units are accepted: 221.Pp 222.Bl -tag -width Ds -offset indent -compact 223.It c 224centimetre 225.It i 226inch 227.It P 228pica (~1/6 inch) 229.It p 230point (~1/72 inch) 231.It f 232synonym for 233.Sq u 234.It v 235default vertical span 236.It m 237width of rendered 238.Sq m 239.Pq em 240character 241.It n 242width of rendered 243.Sq n 244.Pq en 245character 246.It u 247default horizontal span 248.It M 249mini-em (~1/100 em) 250.El 251.Pp 252Using anything other than 253.Sq m , 254.Sq n , 255.Sq u , 256or 257.Sq v 258is necessarily non-portable across output media. 259See 260.Sx COMPATIBILITY . 261.Pp 262If a scaling unit is not provided, the numerical value is interpreted 263under the default rules of 264.Sq v 265for vertical spaces and 266.Sq u 267for horizontal ones. 268.Pp 269Examples: 270.Bl -tag -width ".Bl -tag -width 2i" -offset indent -compact 271.It Li \&.Bl -tag -width 2i 272two-inch tagged list indentation in 273.Xr mdoc 7 274.It Li \&.HP 2i 275two-inch tagged list indentation in 276.Xr man 7 277.It Li \&.sp 2v 278two vertical spaces 279.El 280.Ss Sentence Spacing 281Each sentence should terminate at the end of an input line. 282By doing this, a formatter will be able to apply the proper amount of 283spacing after the end of sentence (unescaped) period, exclamation mark, 284or question mark followed by zero or more non-sentence closing 285delimiters 286.Po 287.Sq \&) , 288.Sq \&] , 289.Sq \&' , 290.Sq \&" 291.Pc . 292.Pp 293The proper spacing is also intelligently preserved if a sentence ends at 294the boundary of a macro line. 295.Pp 296Examples: 297.Bd -literal -offset indent -compact 298Do not end sentences mid-line like this. Instead, 299end a sentence like this. 300A macro would end like this: 301\&.Xr mandoc 1 \&. 302.Ed 303.Sh REQUEST SYNTAX 304A request or macro line consists of: 305.Pp 306.Bl -enum -compact 307.It 308the control character 309.Sq \&. 310or 311.Sq \(aq 312at the beginning of the line, 313.It 314optionally an arbitrary amount of whitespace, 315.It 316the name of the request or the macro, which is one word of arbitrary 317length, terminated by whitespace, 318.It 319and zero or more arguments delimited by whitespace. 320.El 321.Pp 322Thus, the following request lines are all equivalent: 323.Bd -literal -offset indent 324\&.ig end 325\&.ig end 326\&. ig end 327.Ed 328.Sh MACRO SYNTAX 329Macros are provided by the 330.Xr mdoc 7 331and 332.Xr man 7 333languages and can be defined by the 334.Sx \&de 335request. 336When called, they follow the same syntax as requests, except that 337macro arguments may optionally be quoted by enclosing them 338in double quote characters 339.Pq Sq \(dq . 340Quoted text, even if it contains whitespace or would cause 341a macro invocation when unquoted, is always considered literal text. 342Inside quoted text, pairs of double quote characters 343.Pq Sq Qq 344resolve to single double quote characters. 345.Pp 346To be recognised as the beginning of a quoted argument, the opening 347quote character must be preceded by a space character. 348A quoted argument extends to the next double quote character that is not 349part of a pair, or to the end of the input line, whichever comes earlier. 350Leaving out the terminating double quote character at the end of the line 351is discouraged. 352For clarity, if more arguments follow on the same input line, 353it is recommended to follow the terminating double quote character 354by a space character; in case the next character after the terminating 355double quote character is anything else, it is regarded as the beginning 356of the next, unquoted argument. 357.Pp 358Both in quoted and unquoted arguments, pairs of backslashes 359.Pq Sq \e\e 360resolve to single backslashes. 361In unquoted arguments, space characters can alternatively be included 362by preceding them with a backslash 363.Pq Sq \e\~ , 364but quoting is usually better for clarity. 365.Pp 366Examples: 367.Bl -tag -width Ds -offset indent -compact 368.It Li .Fn strlen \(dqconst char *s\(dq 369Group arguments 370.Qq const char *s 371into one function argument. 372If unspecified, 373.Qq const , 374.Qq char , 375and 376.Qq *s 377would be considered separate arguments. 378.It Li .Op \(dqFl a\(dq 379Consider 380.Qq \&Fl a 381as literal text instead of a flag macro. 382.El 383.Sh REQUEST REFERENCE 384The 385.Xr mandoc 1 386.Nm 387parser recognises the following requests. 388Note that the 389.Nm 390language defines many more requests not implemented in 391.Xr mandoc 1 . 392.Ss \&ad 393Set line adjustment mode. 394This line-scoped request is intended to have one argument to select 395normal, left, right, or centre adjustment for subsequent text. 396Currently, it is ignored including its arguments, 397and the number of arguments is not checked. 398.Ss \&am 399Append to a macro definition. 400The syntax of this request is the same as that of 401.Sx \&de . 402It is currently ignored by 403.Xr mandoc 1 , 404as are its children. 405.Ss \&ami 406Append to a macro definition, specifying the macro name indirectly. 407The syntax of this request is the same as that of 408.Sx \&dei . 409It is currently ignored by 410.Xr mandoc 1 , 411as are its children. 412.Ss \&am1 413Append to a macro definition, switching roff compatibility mode off 414during macro execution. 415The syntax of this request is the same as that of 416.Sx \&de1 . 417It is currently ignored by 418.Xr mandoc 1 , 419as are its children. 420.Ss \&de 421Define a 422.Nm 423macro. 424Its syntax can be either 425.Bd -literal -offset indent 426.Pf . Cm \&de Ar name 427.Ar macro definition 428\&.. 429.Ed 430.Pp 431or 432.Bd -literal -offset indent 433.Pf . Cm \&de Ar name Ar end 434.Ar macro definition 435.Pf . Ar end 436.Ed 437.Pp 438Both forms define or redefine the macro 439.Ar name 440to represent the 441.Ar macro definition , 442which may consist of one or more input lines, including the newline 443characters terminating each line, optionally containing calls to 444.Nm 445requests, 446.Nm 447macros or high-level macros like 448.Xr man 7 449or 450.Xr mdoc 7 451macros, whichever applies to the document in question. 452.Pp 453Specifying a custom 454.Ar end 455macro works in the same way as for 456.Sx \&ig ; 457namely, the call to 458.Sq Pf . Ar end 459first ends the 460.Ar macro definition , 461and after that, it is also evaluated as a 462.Nm 463request or 464.Nm 465macro, but not as a high-level macro. 466.Pp 467The macro can be invoked later using the syntax 468.Pp 469.D1 Pf . Ar name Op Ar argument Op Ar argument ... 470.Pp 471Regarding argument parsing, see 472.Sx MACRO SYNTAX 473above. 474.Pp 475The line invoking the macro will be replaced 476in the input stream by the 477.Ar macro definition , 478replacing all occurrences of 479.No \e\e$ Ns Ar N , 480where 481.Ar N 482is a digit, by the 483.Ar N Ns th Ar argument . 484For example, 485.Bd -literal -offset indent 486\&.de ZN 487\efI\e^\e\e$1\e^\efP\e\e$2 488\&.. 489\&.ZN XtFree . 490.Ed 491.Pp 492produces 493.Pp 494.D1 \efI\e^XtFree\e^\efP. 495.Pp 496in the input stream, and thus in the output: \fI\^XtFree\^\fP. 497.Pp 498Since macros and user-defined strings share a common string table, 499defining a macro 500.Ar name 501clobbers the user-defined string 502.Ar name , 503and the 504.Ar macro definition 505can also be printed using the 506.Sq \e* 507string interpolation syntax described below 508.Sx ds , 509but this is rarely useful because every macro definition contains at least 510one explicit newline character. 511.Pp 512In order to prevent endless recursion, both groff and 513.Xr mandoc 1 514limit the stack depth for expanding macros and strings 515to a large, but finite number. 516Do not rely on the exact value of this limit. 517.Ss \&dei 518Define a 519.Nm 520macro, specifying the macro name indirectly. 521The syntax of this request is the same as that of 522.Sx \&de . 523It is currently ignored by 524.Xr mandoc 1 , 525as are its children. 526.Ss \&de1 527Define a 528.Nm 529macro that will be executed with 530.Nm 531compatibility mode switched off during macro execution. 532This is a GNU extension not available in traditional 533.Nm 534implementations and not even in older versions of groff. 535Since 536.Xr mandoc 1 537does not implement 538.Nm 539compatibility mode at all, it handles this request as an alias for 540.Sx \&de . 541.Ss \&ds 542Define a user-defined string. 543Its syntax is as follows: 544.Pp 545.D1 Pf . Cm \&ds Ar name Oo \(dq Oc Ns Ar string 546.Pp 547The 548.Ar name 549and 550.Ar string 551arguments are space-separated. 552If the 553.Ar string 554begins with a double-quote character, that character will not be part 555of the string. 556All remaining characters on the input line form the 557.Ar string , 558including whitespace and double-quote characters, even trailing ones. 559.Pp 560The 561.Ar string 562can be interpolated into subsequent text by using 563.No \e* Ns Bq Ar name 564for a 565.Ar name 566of arbitrary length, or \e*(NN or \e*N if the length of 567.Ar name 568is two or one characters, respectively. 569Interpolation can be prevented by escaping the leading backslash; 570that is, an asterisk preceded by an even number of backslashes 571does not trigger string interpolation. 572.Pp 573Since user-defined strings and macros share a common string table, 574defining a string 575.Ar name 576clobbers the macro 577.Ar name , 578and the 579.Ar name 580used for defining a string can also be invoked as a macro, 581in which case the following input line will be appended to the 582.Ar string , 583forming a new input line passed to the 584.Nm 585parser. 586For example, 587.Bd -literal -offset indent 588\&.ds badidea .S 589\&.badidea 590H SYNOPSIS 591.Ed 592.Pp 593invokes the 594.Cm SH 595macro when used in a 596.Xr man 7 597document. 598Such abuse is of course strongly discouraged. 599.Ss \&el 600The 601.Qq else 602half of an if/else conditional. 603Pops a result off the stack of conditional evaluations pushed by 604.Sx \&ie 605and uses it as its conditional. 606If no stack entries are present (e.g., due to no prior 607.Sx \&ie 608calls) 609then false is assumed. 610The syntax of this request is similar to 611.Sx \&if 612except that the conditional is missing. 613.Ss \&EN 614End an equation block. 615See 616.Sx \&EQ . 617.Ss \&EQ 618Begin an equation block. 619See 620.Xr eqn 7 621for a description of the equation language. 622.Ss \&hy 623Set automatic hyphenation mode. 624This line-scoped request is currently ignored. 625.Ss \&ie 626The 627.Qq if 628half of an if/else conditional. 629The result of the conditional is pushed into a stack used by subsequent 630invocations of 631.Sx \&el , 632which may be separated by any intervening input (or not exist at all). 633Its syntax is equivalent to 634.Sx \&if . 635.Ss \&if 636Begins a conditional. 637Right now, the conditional evaluates to true 638if and only if it starts with the letter 639.Sy n , 640indicating processing in nroff style as opposed to troff style. 641If a conditional is false, its children are not processed, but are 642syntactically interpreted to preserve the integrity of the input 643document. 644Thus, 645.Pp 646.D1 \&.if t .ig 647.Pp 648will discard the 649.Sq \&.ig , 650which may lead to interesting results, but 651.Pp 652.D1 \&.if t .if t \e{\e 653.Pp 654will continue to syntactically interpret to the block close of the final 655conditional. 656Sub-conditionals, in this case, obviously inherit the truth value of 657the parent. 658This request has the following syntax: 659.Bd -literal -offset indent 660\&.if COND \e{\e 661BODY... 662\&.\e} 663.Ed 664.Bd -literal -offset indent 665\&.if COND \e{ BODY 666BODY... \e} 667.Ed 668.Bd -literal -offset indent 669\&.if COND \e{ BODY 670BODY... 671\&.\e} 672.Ed 673.Bd -literal -offset indent 674\&.if COND \e 675BODY 676.Ed 677.Pp 678COND is a conditional statement. 679roff allows for complicated conditionals; mandoc is much simpler. 680At this time, mandoc supports only 681.Sq n , 682evaluating to true; 683and 684.Sq t , 685.Sq e , 686and 687.Sq o , 688evaluating to false. 689All other invocations are read up to the next end of line or space and 690evaluate as false. 691.Pp 692If the BODY section is begun by an escaped brace 693.Sq \e{ , 694scope continues until a closing-brace escape sequence 695.Sq \.\e} . 696If the BODY is not enclosed in braces, scope continues until 697the end of the line. 698If the COND is followed by a BODY on the same line, whether after a 699brace or not, then requests and macros 700.Em must 701begin with a control character. 702It is generally more intuitive, in this case, to write 703.Bd -literal -offset indent 704\&.if COND \e{\e 705\&.foo 706bar 707\&.\e} 708.Ed 709.Pp 710than having the request or macro follow as 711.Pp 712.D1 \&.if COND \e{ .foo 713.Pp 714The scope of a conditional is always parsed, but only executed if the 715conditional evaluates to true. 716.Pp 717Note that the 718.Sq \e} 719is converted into a zero-width escape sequence if not passed as a 720standalone macro 721.Sq \&.\e} . 722For example, 723.Pp 724.D1 \&.Fl a \e} b 725.Pp 726will result in 727.Sq \e} 728being considered an argument of the 729.Sq \&Fl 730macro. 731.Ss \&ig 732Ignore input. 733Its syntax can be either 734.Bd -literal -offset indent 735.Pf . Cm \&ig 736.Ar ignored text 737\&.. 738.Ed 739.Pp 740or 741.Bd -literal -offset indent 742.Pf . Cm \&ig Ar end 743.Ar ignored text 744.Pf . Ar end 745.Ed 746.Pp 747In the first case, input is ignored until a 748.Sq \&.. 749request is encountered on its own line. 750In the second case, input is ignored until the specified 751.Sq Pf . Ar end 752macro is encountered. 753Do not use the escape character 754.Sq \e 755anywhere in the definition of 756.Ar end ; 757it would cause very strange behaviour. 758.Pp 759When the 760.Ar end 761macro is a roff request or a roff macro, like in 762.Pp 763.D1 \&.ig if 764.Pp 765the subsequent invocation of 766.Sx \&if 767will first terminate the 768.Ar ignored text , 769then be invoked as usual. 770Otherwise, it only terminates the 771.Ar ignored text , 772and arguments following it or the 773.Sq \&.. 774request are discarded. 775.Ss \&ne 776Declare the need for the specified minimum vertical space 777before the next trap or the bottom of the page. 778This line-scoped request is currently ignored. 779.Ss \&nh 780Turn off automatic hyphenation mode. 781This line-scoped request is currently ignored. 782.Ss \&rm 783Remove a request, macro or string. 784This request is intended to have one argument, 785the name of the request, macro or string to be undefined. 786Currently, it is ignored including its arguments, 787and the number of arguments is not checked. 788.Ss \&nr 789Define a register. 790A register is an arbitrary string value that defines some sort of state, 791which influences parsing and/or formatting. 792Its syntax is as follows: 793.Pp 794.D1 Pf \. Cm \&nr Ar name Ar value 795.Pp 796The 797.Ar value 798may, at the moment, only be an integer. 799So far, only the following register 800.Ar name 801is recognised: 802.Bl -tag -width Ds 803.It Cm nS 804If set to a positive integer value, certain 805.Xr mdoc 7 806macros will behave in the same way as in the 807.Em SYNOPSIS 808section. 809If set to 0, these macros will behave in the same way as outside the 810.Em SYNOPSIS 811section, even when called within the 812.Em SYNOPSIS 813section itself. 814Note that starting a new 815.Xr mdoc 7 816section with the 817.Cm \&Sh 818macro will reset this register. 819.El 820.Ss \&ns 821Turn on no-space mode. 822This line-scoped request is intended to take no arguments. 823Currently, it is ignored including its arguments, 824and the number of arguments is not checked. 825.Ss \&ps 826Change point size. 827This line-scoped request is intended to take one numerical argument. 828Currently, it is ignored including its arguments, 829and the number of arguments is not checked. 830.Ss \&so 831Include a source file. 832Its syntax is as follows: 833.Pp 834.D1 Pf \. Cm \&so Ar file 835.Pp 836The 837.Ar file 838will be read and its contents processed as input in place of the 839.Sq \&.so 840request line. 841To avoid inadvertent inclusion of unrelated files, 842.Xr mandoc 1 843only accepts relative paths not containing the strings 844.Qq ../ 845and 846.Qq /.. . 847.Pp 848This request requires 849.Xr man 1 850to change to the right directory before calling 851.Xr mandoc 1 , 852per convention to the root of the manual tree. 853Typical usage looks like: 854.Pp 855.Dl \&.so man3/Xcursor.3 856.Pp 857As the whole concept is rather fragile, the use of 858.Sx \&so 859is discouraged. 860Use 861.Xr ln 1 862instead. 863.Ss \&ta 864Set tab stops. 865This line-scoped request can take an arbitrary number of arguments. 866Currently, it is ignored including its arguments. 867.Ss \&tr 868Output character translation. 869Its syntax is as follows: 870.Pp 871.D1 Pf \. Cm \&tr Ar [ab]+ 872.Pp 873Pairs of 874.Ar ab 875characters are replaced 876.Ar ( a 877for 878.Ar b ) . 879Replacement (or origin) characters may also be character escapes; thus, 880.Pp 881.Dl tr \e(xx\e(yy 882.Pp 883replaces all invocations of \e(xx with \e(yy. 884.Ss \&T& 885Re-start a table layout, retaining the options of the prior table 886invocation. 887See 888.Sx \&TS . 889.Ss \&TE 890End a table context. 891See 892.Sx \&TS . 893.Ss \&TS 894Begin a table, which formats input in aligned rows and columns. 895See 896.Xr tbl 7 897for a description of the tbl language. 898.Sh COMPATIBILITY 899This section documents compatibility between mandoc and other other 900.Nm 901implementations, at this time limited to GNU troff 902.Pq Qq groff . 903The term 904.Qq historic groff 905refers to groff version 1.15. 906.Pp 907.Bl -dash -compact 908.It 909In mandoc, the 910.Sx \&EQ , 911.Sx \&TE , 912.Sx \&TS , 913and 914.Sx \&T& , 915macros are considered regular macros. 916In all other 917.Nm 918implementations, these are special macros that must be specified without 919spacing between the control character (which must be a period) and the 920macro name. 921.It 922The 923.Cm nS 924register is only compatible with OpenBSD's groff-1.15. 925.It 926Historic groff did not accept white-space before a custom 927.Ar end 928macro for the 929.Sx \&ig 930request. 931.It 932The 933.Sx \&if 934and family would print funny white-spaces with historic groff when 935using the next-line syntax. 936.El 937.Sh SEE ALSO 938.Xr mandoc 1 , 939.Xr eqn 7 , 940.Xr man 7 , 941.Xr mandoc_char 7 , 942.Xr mdoc 7 , 943.Xr tbl 7 944.Rs 945.%A Joseph F. Ossanna 946.%A Brian W. Kernighan 947.%I AT&T Bell Laboratories 948.%T Troff User's Manual 949.%R Computing Science Technical Report 950.%N 54 951.%C Murray Hill, New Jersey 952.%D 1976 and 1992 953.%U http://www.kohala.com/start/troff/cstr54.ps 954.Re 955.Rs 956.%A Joseph F. Ossanna 957.%A Brian W. Kernighan 958.%A Gunnar Ritter 959.%T Heirloom Documentation Tools Nroff/Troff User's Manual 960.%D September 17, 2007 961.%U http://heirloom.sourceforge.net/doctools/troff.pdf 962.Re 963.Sh HISTORY 964The RUNOFF typesetting system, whose input forms the basis for 965.Nm , 966was written in MAD and FAP for the CTSS operating system by Jerome E. 967Saltzer in 1964. 968Doug McIlroy rewrote it in BCPL in 1969, renaming it 969.Nm . 970Dennis M. Ritchie rewrote McIlroy's 971.Nm 972in PDP-11 assembly for 973.At v1 , 974Joseph F. Ossanna improved roff and renamed it nroff 975for 976.At v2 , 977then ported nroff to C as troff, which Brian W. Kernighan released with 978.At v7 . 979In 1989, James Clarke re-implemented troff in C++, naming it groff. 980.Sh AUTHORS 981.An -nosplit 982This 983.Nm 984reference was written by 985.An Kristaps Dzonsons , 986.Mt kristaps@bsd.lv ; 987and 988.An Ingo Schwarze , 989.Mt schwarze@openbsd.org . 990