===================================================================
RCS file: /cvs/mandoc/eqn.7,v
retrieving revision 1.22
retrieving revision 1.25
diff -u -p -r1.22 -r1.25
--- mandoc/eqn.7	2011/07/23 12:10:16	1.22
+++ mandoc/eqn.7	2011/07/23 19:04:47	1.25
@@ -1,4 +1,4 @@
-.\"	$Id: eqn.7,v 1.22 2011/07/23 12:10:16 kristaps Exp $
+.\"	$Id: eqn.7,v 1.25 2011/07/23 19:04:47 kristaps Exp $
 .\"
 .\" Copyright (c) 2011 Kristaps Dzonsons <kristaps@bsd.lv>
 .\"
@@ -30,11 +30,16 @@ 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 correspond to the Second Edition eqn specification (see
+.Sx SEE ALSO
+for references).
 .Pp
 Equations within
 .Xr mdoc 7
@@ -66,6 +71,8 @@ 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
@@ -77,9 +84,9 @@ box     : text
         | font box
         | \*qsize\*q text box
         | \*qleft\*q text eqn [\*qright\*q text]
-col     : \*qlcol\*q | \*qrcol\*q | \*qccol\*q
+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
@@ -145,6 +152,13 @@ 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:
@@ -173,6 +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:
@@ -185,6 +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