-.\" $Id: roff.7,v 1.71 2015/04/29 18:35:00 schwarze Exp $
+.\" $Id: roff.7,v 1.72 2015/05/31 23:13:22 schwarze Exp $
.\"
.\" Copyright (c) 2010, 2011, 2012 Kristaps Dzonsons <kristaps@bsd.lv>
.\" Copyright (c) 2010, 2011, 2013, 2014 Ingo Schwarze <schwarze@openbsd.org>
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
-.Dd $Mdocdate: April 29 2015 $
+.Dd $Mdocdate: May 31 2015 $
.Dt ROFF 7
.Os
.Sh NAME
.Pq string defined ,
.Sq e
.Pq even page ,
-.Sq r
-.Pq register accessed ,
.Sq t
.Pq troff mode ,
or
.Pq vroff mode ,
COND evaluates to false.
.It
+If the first character of COND is
+.Sq r ,
+it evalutes to true if the rest of COND is the name of an existing
+number register; otherwise, it evaluates to false.
+.It
If COND starts with a parenthesis or with an optionally signed
integer number, it is evaluated according to the rules of
.Sx Numerical expressions