Implement the roff(7) `r' (register exists) conditional.

Missing feature found by Markus <Waldeck at gmx dot de>
in Debian's bash(1) manual page.

1 files changed, 5 insertions, 2 deletions

diff --git a/roff.7 b/roff.7
index d7515f40..d8fc0c04 100644
--- a/roff.7
+++ b/roff.7
@@ -1057,8 +1057,6 @@ If the first character of COND is
 .Pq string defined ,
 .Sq e
 .Pq even page ,
-.Sq r
-.Pq register accessed ,
 .Sq t
 .Pq troff mode ,
 or
@@ -1066,6 +1064,11 @@ 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