Annotation of mandoc/eqn.7, Revision 1.8
1.8 ! kristaps 1: .\" $Id: eqn.7,v 1.7 2011/07/21 11:57:56 kristaps Exp $
1.1 kristaps 2: .\"
3: .\" Copyright (c) 2011 Kristaps Dzonsons <kristaps@bsd.lv>
4: .\"
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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
1.8 ! kristaps 66: | { eqn }
1.3 kristaps 67: | DEFINE text text
68: | SET text text
69: | UNDEF text
70: text : TEXT
71: .Ed
72: .Pp
73: Data in TEXT form is a non-empty sequence of non-space characters or a
74: non-empty quoted string.
1.5 kristaps 75: Unless within a quoted string, white-space (and enclosing literal quote
76: pairs) is thrown away.
1.6 kristaps 77: Quoted strings are not scanned for replacement definitions.
1.3 kristaps 78: .Pp
79: The following control statements are available:
80: .Bl -tag -width Ds
81: .It Cm define
82: Replace all occurances of a key with a value.
83: Its syntax is as follows:
84: .Pp
1.5 kristaps 85: .D1 define Ar key cvalc
86: .Pp
87: The first character of the value string,
88: .Ar c ,
89: is used as the delimiter for the value
90: .Ar val .
91: This allows for arbitrary enclosure of terms (not just quotes), such as
92: .Pp
93: .D1 define Ar foo 'bar baz'
94: .D1 define Ar foo cbar bazc
1.2 kristaps 95: .Pp
1.3 kristaps 96: It is an error to have an empty
97: .Ar key or
1.5 kristaps 98: .Ar val .
1.3 kristaps 99: Note that a quoted
100: .Ar key
101: causes errors in some
1.2 kristaps 102: .Nm
1.3 kristaps 103: implementations and should not be considered portable.
1.7 kristaps 104: It is not expanded for replacements.
1.4 kristaps 105: Definitions may refer to other definitions; these are evaluated
106: recursively when text replacement occurs and not when the definition is
107: created.
1.5 kristaps 108: .Pp
109: Definitions can create arbitrary strings, for example, the following is
110: a legal construction.
111: .Bd -literal -offset indent
112: define foo 'define'
113: foo bar 'baz'
114: .Ed
115: .Pp
1.4 kristaps 116: Self-referencing definitions will raise an error.
1.3 kristaps 117: .It Cm set
1.4 kristaps 118: Set an equation mode.
1.3 kristaps 119: Both arguments are thrown away.
1.7 kristaps 120: Its syntax is as follows:
121: .Pp
122: .D1 set Ar key val
123: .Pp
124: The
125: .Ar key
126: and
127: .Ar val
128: are not expanded for replacements.
1.3 kristaps 129: .It Cm undef
130: Unset a previously-defined key.
131: Its syntax is as follows:
132: .Pp
133: .D1 define Ar key
1.2 kristaps 134: .Pp
1.3 kristaps 135: Once invoked, the definition for
136: .Ar key
137: is discarded.
1.7 kristaps 138: The
139: .Ar key
140: is not expanded for replacements.
1.3 kristaps 141: .El
1.5 kristaps 142: .Sh COMPATIBILITY
143: This section documents the compatibility of mandoc
144: .Nm
145: and the troff
146: .Nm
147: implementation (including GNU troff).
148: .Pp
149: .Bl -dash -compact
150: .It
151: The text string
152: .Sq \e\*q
153: is interpreted as a literal quote in troff.
154: In mandoc, this is interpreted as a comment.
155: .El
1.1 kristaps 156: .Sh SEE ALSO
157: .Xr mandoc 1 ,
158: .Xr man 7 ,
159: .Xr mandoc_char 7 ,
160: .Xr mdoc 7 ,
161: .Xr roff 7
162: .Rs
163: .%A Brian W. Kernighan
164: .%A Lorinda L. Cherry
165: .%T System for Typesetting Mathematics
166: .%J Communications of the ACM
167: .%V 18
168: .%P 151\(en157
169: .%D March, 1975
170: .Re
1.5 kristaps 171: .Rs
172: .%A Brian W. Kernighan
173: .%A Lorinda L. Cherry
174: .%T Typesetting Mathematics, User's Guide
175: .%D 1976
176: .Re
177: .Rs
178: .%A Brian W. Kernighan
179: .%A Lorinda L. Cherry
180: .%T Typesetting Mathematics, User's Guide (Second Edition)
181: .%D 1978
182: .Re
183: .Sh HISTORY
184: The eqn utility, a preprocessor for troff, was originally written by
185: Brian W. Kernighan and Lorinda L. Cherry in 1975.
186: The GNU reimplementation of eqn, part of the GNU troff package, was
187: released in 1989 by James Clark.
188: The eqn component of
189: .Xr mandoc 1
190: was added in 2011.
1.1 kristaps 191: .Sh AUTHORS
1.5 kristaps 192: This
1.1 kristaps 193: .Nm
194: reference was written by
195: .An Kristaps Dzonsons Aq kristaps@bsd.lv .
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