===================================================================
RCS file: /cvs/mandoc/eqn.7,v
retrieving revision 1.14
retrieving revision 1.30
diff -u -p -r1.14 -r1.30
--- mandoc/eqn.7	2011/07/22 12:55:02	1.14
+++ mandoc/eqn.7	2014/10/10 08:44:24	1.30
@@ -1,4 +1,4 @@
-.\"	$Id: eqn.7,v 1.14 2011/07/22 12:55:02 kristaps Exp $
+.\"	$Id: eqn.7,v 1.30 2014/10/10 08:44:24 kristaps Exp $
 .\"
 .\" 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.
 .\"
-.Dd $Mdocdate: July 22 2011 $
+.Dd $Mdocdate: October 10 2014 $
 .Dt EQN 7
 .Os
 .Sh NAME
@@ -23,18 +23,23 @@
 .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.
-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
-utility.
+utility, which corresponds to the Second Edition eqn specification (see
+.Sx SEE ALSO
+for references).
 .Pp
 Equations within
 .Xr mdoc 7
@@ -59,53 +64,59 @@ these are not the same as
 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
-        | { eqn }
-        | DEFINE text text
-        | SET text text
-        | UNDEF 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
-        | pile { list }
+        | \*qmatrix\*q \*q{\*q [col \*q{\*q list \*q}\*q ]*
+        | pile \*q{\*q list \*q}\*q
         | font box
-        | SIZE text box
-        | LEFT text eqn [RIGHT text]
-text    : TEXT
-pile    : LPILE
-        | CPILE
-        | RPILE
-pos     : OVER
-        | SUP
-        | SUB
-        | TO
-        | FROM
-mark	: DOT
-        | DOTDOT
-        | HAT
-        | TILDE
-        | VEC
-        | DYAD
-        | BAR
-        | UNDER
-font    : ROMAN
-        | ITALIC
-        | BOLD
-list    : eqn | list ABOVE eqn
+        | \*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
-Data in TEXT form is a non-empty sequence of non-space characters or a
-non-empty quoted string.
-Unless within a quoted string, white-space (and enclosing literal quote
-pairs) is thrown away.
-Quoted strings are not scanned for replacement definitions.
+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
-Replace all occurances of a key with a value.
+Replace all occurrences of a key with a value.
 Its syntax is as follows:
 .Pp
 .D1 define Ar key cvalc
@@ -120,7 +131,8 @@ This allows for arbitrary enclosure of terms (not just
 .D1 define Ar foo cbar bazc
 .Pp
 It is an error to have an empty
-.Ar key or
+.Ar key
+or
 .Ar val .
 Note that a quoted
 .Ar key
@@ -140,9 +152,32 @@ foo bar 'baz'
 .Ed
 .Pp
 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.
-Both arguments are thrown away.
+In mandoc, both arguments are thrown away.
 Its syntax is as follows:
 .Pp
 .D1 set Ar key val
@@ -152,6 +187,7 @@ The
 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:
@@ -164,6 +200,7 @@ 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
@@ -178,6 +215,26 @@ 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 ,
@@ -207,7 +264,7 @@ In mandoc, this is interpreted as a comment.
 .%D 1978
 .Re
 .Sh HISTORY
-The eqn utility, a preprocessor for troff, was originally written by 
+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.
@@ -218,4 +275,4 @@ was added in 2011.
 This
 .Nm
 reference was written by
-.An Kristaps Dzonsons Aq kristaps@bsd.lv .
+.An Kristaps Dzonsons Aq Mt kristaps@bsd.lv .