===================================================================
RCS file: /cvs/mandoc/eqn.7,v
retrieving revision 1.19
retrieving revision 1.28
diff -u -p -r1.19 -r1.28
--- mandoc/eqn.7	2011/07/23 09:47:25	1.19
+++ mandoc/eqn.7	2011/09/25 18:37:09	1.28
@@ -1,4 +1,4 @@
-.\"	$Id: eqn.7,v 1.19 2011/07/23 09:47:25 kristaps Exp $
+.\"	$Id: eqn.7,v 1.28 2011/09/25 18:37:09 schwarze 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 23 2011 $
+.Dd $Mdocdate: September 25 2011 $
 .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
@@ -66,22 +71,26 @@ eqn     : box | eqn box
 box     : text
         | \*q{\*q eqn \*q}\*q
         | \*qdefine\*q text text
+        | \*qndefine\*q text text
+        | \*qtdefine\*q text text
         | \*qgfont\*q text
         | \*qgsize\*q text
         | \*qset\*q text 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
+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
+font    : \*qroman\*q | \*qitalic\*q | \*qbold\*q | \*qfat\*q
 list    : eqn
         | list \*qabove\*q eqn
 space   : [\e^~ \et]
@@ -108,7 +117,7 @@ partial (partial differential), inf (infinity), >> (mu
 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
@@ -123,7 +132,8 @@ 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
@@ -143,6 +153,13 @@ 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:
@@ -171,6 +188,7 @@ 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:
@@ -183,6 +201,7 @@ 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
@@ -201,6 +220,22 @@ In mandoc, this is interpreted as a comment.
 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 ,
@@ -241,4 +276,5 @@ was added in 2011.
 This
 .Nm
 reference was written by
-.An Kristaps Dzonsons Aq kristaps@bsd.lv .
+.An Kristaps Dzonsons ,
+.Mt kristaps@bsd.lv .