eqn.7

   1 .\"     $Id: eqn.7,v 1.3 2011/07/17 14:08:49 kristaps Exp $
   2 .\"
   3 .\" Copyright (c) 2011 Kristaps Dzonsons <kristaps@bsd.lv>
   4 .\"
   5 .\" Permission to use, copy, modify, and distribute this software for any
   6 .\" purpose with or without fee is hereby granted, provided that the above
   7 .\" copyright notice and this permission notice appear in all copies.
   8 .\"
   9 .\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  10 .\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  11 .\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  12 .\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  13 .\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  14 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  15 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  16 .\"
  17 .Dd $Mdocdate: July 17 2011 $
  18 .Dt EQN 7
  19 .Os
  20 .Sh NAME
  21 .Nm eqn
  22 .Nd eqn language reference for mandoc
  23 .Sh DESCRIPTION
  24 The
  25 .Nm eqn
  26 language is a equation-formatting language.
  27 It is used within
  28 .Xr mdoc 7
  29 and
  30 .Xr man 7
  31 .Ux
  32 manual pages.
  33 This manual describes the subset of the
  34 .Nm
  35 language accepted by the
  36 .Xr mandoc 1
  37 utility.
  38 .Pp
  39 Equations within
  40 .Xr mdoc 7
  41 or
  42 .Xr man 7
  43 documents are enclosed by the standalone
  44 .Sq \&.EQ
  45 and
  46 .Sq \&.EN
  47 tags.
  48 Equations are multi-line blocks consisting of formulas and control
  49 statements.
  50 .Sh EQUATION STRUCTURE
  51 Each equation is bracketed by
  52 .Sq \&.EQ
  53 and
  54 .Sq \&.EN
  55 strings.
  56 .Em Note :
  57 these are not the same as
  58 .Xr roff 7
  59 macros, and may only be invoked as
  60 .Sq \&.EQ .
  61 .Pp
  62 The equation grammar is as follows:
  63 .Bd -literal -offset indent
  64 eqn     : box | eqn box
  65 box     : text
  66         | DEFINE text text
  67         | SET text text
  68         | UNDEF text
  69 text    : TEXT
  70 .Ed
  71 .Pp
  72 Data in TEXT form is a non-empty sequence of non-space characters or a
  73 non-empty quoted string.
  74 White-space (and enclosing literal quote pairs) is thrown away and
  75 productions may not be broken by newlines.
  76 .Pp
  77 The following control statements are available:
  78 .Bl -tag -width Ds
  79 .It Cm define
  80 Replace all occurances of a key with a value.
  81 Its syntax is as follows:
  82 .Pp
  83 .D1 define Ar key val
  84 .Pp
  85 It is an error to have an empty
  86 .Ar key or
  87 .Ar value .
  88 Note that a quoted
  89 .Ar key
  90 causes errors in some
  91 .Nm
  92 implementations and should not be considered portable.
  93 .It Cm set
  94 Set an equation mode.
  95 Both arguments are thrown away.
  96 .It Cm undef
  97 Unset a previously-defined key.
  98 Its syntax is as follows:
  99 .Pp
 100 .D1 define Ar key
 101 .Pp
 102 Once invoked, the definition for
 103 .Ar key
 104 is discarded.
 105 .El
 106 .Sh SEE ALSO
 107 .Xr mandoc 1 ,
 108 .Xr man 7 ,
 109 .Xr mandoc_char 7 ,
 110 .Xr mdoc 7 ,
 111 .Xr roff 7
 112 .Rs
 113 .%A Brian W. Kernighan
 114 .%A Lorinda L. Cherry
 115 .%T System for Typesetting Mathematics
 116 .%J Communications of the ACM
 117 .%V 18
 118 .%P 151\(en157
 119 .%D March, 1975
 120 .Re
 121 .\" .Sh HISTORY
 122 .\" The tbl utility, a preprocessor for troff, was originally written by M.
 123 .\" E. Lesk at Bell Labs in 1975.
 124 .\" The GNU reimplementation of tbl, part of the groff package, was released
 125 .\" in 1990 by James Clark.
 126 .\" A standalone tbl implementation was written by Kristaps Dzonsons in
 127 .\" 2010.
 128 .\" This formed the basis of the implementation that is part of the
 129 .\" .Xr mandoc 1
 130 .\" utility.
 131 .Sh AUTHORS
 132 This partial
 133 .Nm
 134 reference was written by
 135 .An Kristaps Dzonsons Aq kristaps@bsd.lv .