Annotation of mandoc/eqn.7, Revision 1.7
1.7 ! kristaps 1: .\" $Id: eqn.7,v 1.6 2011/07/21 11:34:53 kristaps Exp $
1.1 kristaps 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
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1.6 kristaps 17: .Dd $Mdocdate: July 21 2011 $
1.1 kristaps 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
1.3 kristaps 43: documents are enclosed by the standalone
44: .Sq \&.EQ
1.1 kristaps 45: and
1.3 kristaps 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.
1.5 kristaps 74: Unless within a quoted string, white-space (and enclosing literal quote
75: pairs) is thrown away.
1.6 kristaps 76: Quoted strings are not scanned for replacement definitions.
1.3 kristaps 77: .Pp
78: The following control statements are available:
79: .Bl -tag -width Ds
80: .It Cm define
81: Replace all occurances of a key with a value.
82: Its syntax is as follows:
83: .Pp
1.5 kristaps 84: .D1 define Ar key cvalc
85: .Pp
86: The first character of the value string,
87: .Ar c ,
88: is used as the delimiter for the value
89: .Ar val .
90: This allows for arbitrary enclosure of terms (not just quotes), such as
91: .Pp
92: .D1 define Ar foo 'bar baz'
93: .D1 define Ar foo cbar bazc
1.2 kristaps 94: .Pp
1.3 kristaps 95: It is an error to have an empty
96: .Ar key or
1.5 kristaps 97: .Ar val .
1.3 kristaps 98: Note that a quoted
99: .Ar key
100: causes errors in some
1.2 kristaps 101: .Nm
1.3 kristaps 102: implementations and should not be considered portable.
1.7 ! kristaps 103: It is not expanded for replacements.
1.4 kristaps 104: Definitions may refer to other definitions; these are evaluated
105: recursively when text replacement occurs and not when the definition is
106: created.
1.5 kristaps 107: .Pp
108: Definitions can create arbitrary strings, for example, the following is
109: a legal construction.
110: .Bd -literal -offset indent
111: define foo 'define'
112: foo bar 'baz'
113: .Ed
114: .Pp
1.4 kristaps 115: Self-referencing definitions will raise an error.
1.3 kristaps 116: .It Cm set
1.4 kristaps 117: Set an equation mode.
1.3 kristaps 118: Both arguments are thrown away.
1.7 ! kristaps 119: Its syntax is as follows:
! 120: .Pp
! 121: .D1 set Ar key val
! 122: .Pp
! 123: The
! 124: .Ar key
! 125: and
! 126: .Ar val
! 127: are not expanded for replacements.
1.3 kristaps 128: .It Cm undef
129: Unset a previously-defined key.
130: Its syntax is as follows:
131: .Pp
132: .D1 define Ar key
1.2 kristaps 133: .Pp
1.3 kristaps 134: Once invoked, the definition for
135: .Ar key
136: is discarded.
1.7 ! kristaps 137: The
! 138: .Ar key
! 139: is not expanded for replacements.
1.3 kristaps 140: .El
1.5 kristaps 141: .Sh COMPATIBILITY
142: This section documents the compatibility of mandoc
143: .Nm
144: and the troff
145: .Nm
146: implementation (including GNU troff).
147: .Pp
148: .Bl -dash -compact
149: .It
150: The text string
151: .Sq \e\*q
152: is interpreted as a literal quote in troff.
153: In mandoc, this is interpreted as a comment.
154: .El
1.1 kristaps 155: .Sh SEE ALSO
156: .Xr mandoc 1 ,
157: .Xr man 7 ,
158: .Xr mandoc_char 7 ,
159: .Xr mdoc 7 ,
160: .Xr roff 7
161: .Rs
162: .%A Brian W. Kernighan
163: .%A Lorinda L. Cherry
164: .%T System for Typesetting Mathematics
165: .%J Communications of the ACM
166: .%V 18
167: .%P 151\(en157
168: .%D March, 1975
169: .Re
1.5 kristaps 170: .Rs
171: .%A Brian W. Kernighan
172: .%A Lorinda L. Cherry
173: .%T Typesetting Mathematics, User's Guide
174: .%D 1976
175: .Re
176: .Rs
177: .%A Brian W. Kernighan
178: .%A Lorinda L. Cherry
179: .%T Typesetting Mathematics, User's Guide (Second Edition)
180: .%D 1978
181: .Re
182: .Sh HISTORY
183: The eqn utility, a preprocessor for troff, was originally written by
184: Brian W. Kernighan and Lorinda L. Cherry in 1975.
185: The GNU reimplementation of eqn, part of the GNU troff package, was
186: released in 1989 by James Clark.
187: The eqn component of
188: .Xr mandoc 1
189: was added in 2011.
1.1 kristaps 190: .Sh AUTHORS
1.5 kristaps 191: This
1.1 kristaps 192: .Nm
193: reference was written by
194: .An Kristaps Dzonsons Aq kristaps@bsd.lv .
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