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.

2 files changed, 39 insertions, 10 deletions

diff --git a/roff.7 b/roff.7
index 02b7212e..127504f8 100644
--- a/roff.7
+++ b/roff.7
@@ -1,4 +1,4 @@
-.\"	$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>
@@ -15,7 +15,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: April 29 2015 $
+.Dd $Mdocdate: May 31 2015 $
 .Dt ROFF 7
 .Os
 .Sh NAME
@@ -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
diff --git a/roff.c b/roff.c
index 31bed07a..0dfcb46c 100644
--- a/roff.c
+++ b/roff.c
@@ -1,4 +1,4 @@
-/*	$Id: roff.c,v 1.270 2015/05/01 16:02:47 schwarze Exp $ */
+/*	$Id: roff.c,v 1.271 2015/05/31 23:13:22 schwarze Exp $ */
 /*
  * Copyright (c) 2008-2012, 2014 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2010-2015 Ingo Schwarze <schwarze@openbsd.org>
@@ -397,8 +397,7 @@ static	enum rofferr	 roff_cond_text(ROFF_ARGS);
 static	enum rofferr	 roff_cond_sub(ROFF_ARGS);
 static	enum rofferr	 roff_ds(ROFF_ARGS);
 static	enum rofferr	 roff_eqndelim(struct roff *, struct buf *, int);
-static	int		 roff_evalcond(struct roff *r, int,
-				const char *, int *);
+static	int		 roff_evalcond(struct roff *r, int, char *, int *);
 static	int		 roff_evalnum(struct roff *, int,
 				const char *, int *, int *, int);
 static	int		 roff_evalpar(struct roff *, int,
@@ -415,6 +414,8 @@ static	int		 roff_getregn(const struct roff *,
 static	int		 roff_getregro(const char *name);
 static	const char	*roff_getstrn(const struct roff *,
 				const char *, size_t);
+static	int		 roff_hasregn(const struct roff *,
+				const char *, size_t);
 static	enum rofferr	 roff_insec(ROFF_ARGS);
 static	enum rofferr	 roff_it(ROFF_ARGS);
 static	enum rofferr	 roff_line_ignore(ROFF_ARGS);
@@ -2134,8 +2135,10 @@ out:
  * or string condition.
  */
 static int
-roff_evalcond(struct roff *r, int ln, const char *v, int *pos)
+roff_evalcond(struct roff *r, int ln, char *v, int *pos)
 {
+	char	*cp, *name;
+	size_t	 sz;
 	int	 number, savepos, wanttrue;
 
 	if ('!' == v[*pos]) {
@@ -2158,13 +2161,16 @@ roff_evalcond(struct roff *r, int ln, const char *v, int *pos)
 		/* FALLTHROUGH */
 	case 'e':
 		/* FALLTHROUGH */
-	case 'r':
-		/* FALLTHROUGH */
 	case 't':
 		/* FALLTHROUGH */
 	case 'v':
 		(*pos)++;
 		return(!wanttrue);
+	case 'r':
+		cp = name = v + ++*pos;
+		sz = roff_getname(r, &cp, ln, *pos);
+		*pos = cp - v;
+		return((sz && roff_hasregn(r, name, sz)) == wanttrue);
 	default:
 		break;
 	}
@@ -2627,6 +2633,26 @@ roff_getregn(const struct roff *r, const char *name, size_t len)
 	return(0);
 }
 
+static int
+roff_hasregn(const struct roff *r, const char *name, size_t len)
+{
+	struct roffreg	*reg;
+	int		 val;
+
+	if ('.' == name[0] && 2 == len) {
+		val = roff_getregro(name + 1);
+		if (-1 != val)
+			return(1);
+	}
+
+	for (reg = r->regtab; reg; reg = reg->next)
+		if (len == reg->key.sz &&
+		    0 == strncmp(name, reg->key.p, len))
+			return(1);
+
+	return(0);
+}
+
 static void
 roff_freereg(struct roffreg *reg)
 {