Drop trailing whitespace, adjust a few indentations,

[mandoc.git] / eqn.7

diff --git a/eqn.7 b/eqn.7
index 1eaf156fd657ab13b473a78471ad719492ff1d85..ba8164c267f7d572986329cc4f8b783fd818f252 100644 (file)
--- a/eqn.7
+++ b/eqn.7
@@ -1,4 +1,4 @@
-.\"    $Id: eqn.7,v 1.4 2011/07/18 13:47:38 kristaps Exp $
+.\"    $Id: eqn.7,v 1.30 2014/10/10 08:44:24 kristaps Exp $

 .\"
 .\" Copyright (c) 2011 Kristaps Dzonsons <kristaps@bsd.lv>
 .\"
 .\"
 .\" Copyright (c) 2011 Kristaps Dzonsons <kristaps@bsd.lv>
 .\"


@@ -14,7 +14,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"

-.Dd $Mdocdate: July 18 2011 $
+.Dd $Mdocdate: October 10 2014 $

 .Dt EQN 7
 .Os
 .Sh NAME
 .Dt EQN 7
 .Os
 .Sh NAME


@@ -23,18 +23,23 @@
 .Sh DESCRIPTION
 The
 .Nm eqn
 .Sh DESCRIPTION
 The
 .Nm eqn

-language is a equation-formatting language.
+language is an equation-formatting language.

 It is used within
 .Xr mdoc 7
 and
 .Xr man 7
 .Ux
 manual pages.
 It is used within
 .Xr mdoc 7
 and
 .Xr man 7
 .Ux
 manual pages.

-This manual describes the subset of the
+It describes the
+.Em structure
+of an equation, not its mathematical meaning.
+This manual describes the

 .Nm
 language accepted by the
 .Xr mandoc 1
 .Nm
 language accepted by the
 .Xr mandoc 1

-utility.
+utility, which corresponds to the Second Edition eqn specification (see
+.Sx SEE ALSO
+for references).

 .Pp
 Equations within
 .Xr mdoc 7
 .Pp
 Equations within
 .Xr mdoc 7


@@ -59,44 +64,130 @@ these are not the same as
 macros, and may only be invoked as
 .Sq \&.EQ .
 .Pp
 macros, and may only be invoked as
 .Sq \&.EQ .
 .Pp

-The equation grammar is as follows:
+The equation grammar is as follows, where quoted strings are
+case-sensitive literals in the input:

 .Bd -literal -offset indent
 eqn     : box | eqn box
 box     : text
 .Bd -literal -offset indent
 eqn     : box | eqn box
 box     : text

-        | DEFINE text text
-        | SET text text
-        | UNDEF text
-text    : TEXT
+        | \*q{\*q eqn \*q}\*q
+        | \*qdefine\*q text text
+        | \*qndefine\*q text text
+        | \*qtdefine\*q text text
+        | \*qgfont\*q text
+        | \*qgsize\*q text
+        | \*qundef\*q text
+        | box pos box
+        | box mark
+        | \*qmatrix\*q \*q{\*q [col \*q{\*q list \*q}\*q ]*
+        | pile \*q{\*q list \*q}\*q
+        | font box
+        | \*qsize\*q text box
+        | \*qleft\*q text eqn [\*qright\*q text]
+col     : \*qlcol\*q | \*qrcol\*q | \*qccol\*q | \*qcol\*q
+text    : [^space\e\*q]+ | \e\*q.*\e\*q
+pile    : \*qlpile\*q | \*qcpile\*q | \*qrpile\*q | \*qpile\*q
+pos     : \*qover\*q | \*qsup\*q | \*qsub\*q | \*qto\*q | \*qfrom\*q
+mark   : \*qdot\*q | \*qdotdot\*q | \*qhat\*q | \*qtilde\*q | \*qvec\*q
+        | \*qdyad\*q | \*qbar\*q | \*qunder\*q
+font    : \*qroman\*q | \*qitalic\*q | \*qbold\*q | \*qfat\*q
+list    : eqn
+        | list \*qabove\*q eqn
+space   : [\e^~ \et]

 .Ed
 .Pp
 .Ed
 .Pp

-Data in TEXT form is a non-empty sequence of non-space characters or a
-non-empty quoted string.
-White-space (and enclosing literal quote pairs) is thrown away and
-productions may not be broken by newlines.
+White-space consists of the space, tab, circumflex, and tilde
+characters.
+If within a quoted string, these space characters are retained.
+Quoted strings are also not scanned for replacement definitions.
+.Pp
+The following text terms are translated into a rendered glyph, if
+available: alpha, beta, chi, delta, epsilon, eta, gamma, iota, kappa,
+lambda, mu, nu, omega, omicron, phi, pi, psi, rho, sigma, tau, theta,
+upsilon, xi, zeta, DELTA, GAMMA, LAMBDA, OMEGA, PHI, PI, PSI, SIGMA,
+THETA, UPSILON, XI, inter (intersection), union (union), prod (product),
+int (integral), sum (summation), grad (gradient), del (vector
+differential), times (multiply), cdot (centre-dot), nothing (zero-width
+space), approx (approximately equals), prime (prime), half (one-half),
+partial (partial differential), inf (infinity), >> (much greater), <<
+(much less), \-> (left arrow), <\- (right arrow), += (plus-minus), !=
+(not equal), == (equivalence), <= (less-than-equal), and >=
+(more-than-equal).

 .Pp
 The following control statements are available:
 .Bl -tag -width Ds
 .It Cm define
 .Pp
 The following control statements are available:
 .Bl -tag -width Ds
 .It Cm define

-Replace all occurances of a key with a value.
+Replace all occurrences of a key with a value.

 Its syntax is as follows:
 .Pp
 Its syntax is as follows:
 .Pp

-.D1 define Ar key val
+.D1 define Ar key cvalc
+.Pp
+The first character of the value string,
+.Ar c ,
+is used as the delimiter for the value
+.Ar val .
+This allows for arbitrary enclosure of terms (not just quotes), such as
+.Pp
+.D1 define Ar foo 'bar baz'
+.D1 define Ar foo cbar bazc

 .Pp
 It is an error to have an empty
 .Pp
 It is an error to have an empty

-.Ar key or
-.Ar value .
+.Ar key
+or
+.Ar val .

 Note that a quoted
 .Ar key
 causes errors in some
 .Nm
 implementations and should not be considered portable.
 Note that a quoted
 .Ar key
 causes errors in some
 .Nm
 implementations and should not be considered portable.

+It is not expanded for replacements.

 Definitions may refer to other definitions; these are evaluated
 recursively when text replacement occurs and not when the definition is
 created.
 Definitions may refer to other definitions; these are evaluated
 recursively when text replacement occurs and not when the definition is
 created.

+.Pp
+Definitions can create arbitrary strings, for example, the following is
+a legal construction.
+.Bd -literal -offset indent
+define foo 'define'
+foo bar 'baz'
+.Ed
+.Pp

 Self-referencing definitions will raise an error.
 Self-referencing definitions will raise an error.

+The
+.Cm ndefine
+statement is a synonym for
+.Cm define ,
+while
+.Cm tdefine
+is discarded.
+.It Cm gfont
+Set the default font of subsequent output.
+Its syntax is as follows:
+.Pp
+.D1 gfont Ar font
+.Pp
+In mandoc, this value is discarded.
+.It Cm gsize
+Set the default size of subsequent output.
+Its syntax is as follows:
+.Pp
+.D1 gsize Ar size
+.Pp
+The
+.Ar size
+value should be an integer.

 .It Cm set
 Set an equation mode.
 .It Cm set
 Set an equation mode.

-Both arguments are thrown away.
+In mandoc, both arguments are thrown away.
+Its syntax is as follows:
+.Pp
+.D1 set Ar key val
+.Pp
+The
+.Ar key
+and
+.Ar val
+are not expanded for replacements.
+This statement is a GNU extension.

 .It Cm undef
 Unset a previously-defined key.
 Its syntax is as follows:
 .It Cm undef
 Unset a previously-defined key.
 Its syntax is as follows:


@@ -106,6 +197,44 @@ Its syntax is as follows:
 Once invoked, the definition for
 .Ar key
 is discarded.
 Once invoked, the definition for
 .Ar key
 is discarded.

+The
+.Ar key
+is not expanded for replacements.
+This statement is a GNU extension.
+.El
+.Sh COMPATIBILITY
+This section documents the compatibility of mandoc
+.Nm
+and the troff
+.Nm
+implementation (including GNU troff).
+.Pp
+.Bl -dash -compact
+.It
+The text string
+.Sq \e\*q
+is interpreted as a literal quote in troff.
+In mandoc, this is interpreted as a comment.
+.It
+In troff, The circumflex and tilde white-space symbols map to
+fixed-width spaces.
+In mandoc, these characters are synonyms for the space character.
+.It
+The troff implementation of
+.Nm
+allows for equation alignment with the
+.Cm mark
+and
+.Cm lineup
+tokens.
+mandoc discards these tokens.
+The
+.Cm back Ar n ,
+.Cm fwd Ar n ,
+.Cm up Ar n ,
+and
+.Cm down Ar n
+commands are also ignored.

 .El
 .Sh SEE ALSO
 .Xr mandoc 1 ,
 .El
 .Sh SEE ALSO
 .Xr mandoc 1 ,


@@ -122,18 +251,28 @@ is discarded.
 .%P 151\(en157
 .%D March, 1975
 .Re
 .%P 151\(en157
 .%D March, 1975
 .Re

-.\" .Sh HISTORY
-.\" The tbl utility, a preprocessor for troff, was originally written by M.
-.\" E. Lesk at Bell Labs in 1975.
-.\" The GNU reimplementation of tbl, part of the groff package, was released
-.\" in 1990 by James Clark.
-.\" A standalone tbl implementation was written by Kristaps Dzonsons in
-.\" 2010.
-.\" This formed the basis of the implementation that is part of the
-.\" .Xr mandoc 1
-.\" utility.
+.Rs
+.%A Brian W. Kernighan
+.%A Lorinda L. Cherry
+.%T Typesetting Mathematics, User's Guide
+.%D 1976
+.Re
+.Rs
+.%A Brian W. Kernighan
+.%A Lorinda L. Cherry
+.%T Typesetting Mathematics, User's Guide (Second Edition)
+.%D 1978
+.Re
+.Sh HISTORY
+The eqn utility, a preprocessor for troff, was originally written by
+Brian W. Kernighan and Lorinda L. Cherry in 1975.
+The GNU reimplementation of eqn, part of the GNU troff package, was
+released in 1989 by James Clark.
+The eqn component of
+.Xr mandoc 1
+was added in 2011.

 .Sh AUTHORS
 .Sh AUTHORS

-This partial
+This

 .Nm
 reference was written by
 .Nm
 reference was written by

-.An Kristaps Dzonsons Aq kristaps@bsd.lv .
+.An Kristaps Dzonsons Aq Mt kristaps@bsd.lv .