The "value" argument to the roff(7) .nr requests ends right before

the first non-digit character.  While here, implement and document
an optional sign, requesting increment or decrement, as documented
in the Ossanna/Kernighan/Ritter troff manual and supported by groff.

Reported by bentley@ on discuss at mdocml.

9 files changed, 79 insertions, 19 deletions

diff --git a/regress/usr.bin/mandoc/roff/nr/Makefile b/regress/usr.bin/mandoc/roff/nr/Makefile
index ed0ad3c5ad1..82dfd046182 100644
--- a/regress/usr.bin/mandoc/roff/nr/Makefile
+++ b/regress/usr.bin/mandoc/roff/nr/Makefile
@@ -1,5 +1,5 @@
-# $OpenBSD: Makefile,v 1.1 2013/10/03 22:04:07 schwarze Exp $
+# $OpenBSD: Makefile,v 1.2 2013/12/15 21:18:00 schwarze Exp $
 
-REGRESS_TARGETS = int
+REGRESS_TARGETS = int argc
 
 .include <bsd.regress.mk>
diff --git a/regress/usr.bin/mandoc/roff/nr/argc.in b/regress/usr.bin/mandoc/roff/nr/argc.in
new file mode 100644
index 00000000000..bf204a70a2a
--- /dev/null
+++ b/regress/usr.bin/mandoc/roff/nr/argc.in
@@ -0,0 +1,21 @@
+.Dd December 15, 2013
+.Dt NR-ARGC 1
+.Os OpenBSD
+.Sh NAME
+.Nm nr-argc
+.Nd varying number of arguments to the .nr macro
+.Sh DESCRIPTION
+.nr onearg
+one argument: \n[onearg]
+.Pp
+.nr twoargs 2
+two arguments: \n[twoargs]
+.Pp
+.nr withsuffix 2x
+with suffix: \n[withsuffix]
+.Pp
+.nr threeargs 2 3
+three arguments: \n[threeargs]
+.Pp
+.nr fourargs 2 3 4
+four arguments: \n[fourargs]
diff --git a/regress/usr.bin/mandoc/roff/nr/argc.out_ascii b/regress/usr.bin/mandoc/roff/nr/argc.out_ascii
new file mode 100644
index 00000000000..82c86bfd3a4
--- /dev/null
+++ b/regress/usr.bin/mandoc/roff/nr/argc.out_ascii
@@ -0,0 +1,17 @@
+NR-ARGC(1)                 OpenBSD Reference Manual                 NR-ARGC(1)
+
+NNAAMMEE
+     nnrr--aarrggcc - varying number of arguments to the .nr macro
+
+DDEESSCCRRIIPPTTIIOONN
+     one argument: 0
+
+     two arguments: 2
+
+     with suffix: 2
+
+     three arguments: 2
+
+     four arguments: 2
+
+OpenBSD                        December 15, 2013                       OpenBSD
diff --git a/regress/usr.bin/mandoc/roff/nr/int.in b/regress/usr.bin/mandoc/roff/nr/int.in
index 8dd7c477f3f..3f907697a54 100644
--- a/regress/usr.bin/mandoc/roff/nr/int.in
+++ b/regress/usr.bin/mandoc/roff/nr/int.in
@@ -7,4 +7,9 @@ initial contents: \nY \n(YY \n[YYY]
 .nr Y 42
 .nr YY -1
 .nr YYY 2147483647
+intermediate contents: \nY \n(YY \n[YYY]
+.br
+.nr Y -19
+.nr YY +2
+.nr YYY +1
 final contents: \nY \n(YY \n[YYY]
diff --git a/regress/usr.bin/mandoc/roff/nr/int.out_ascii b/regress/usr.bin/mandoc/roff/nr/int.out_ascii
index 8da2aa50eda..638321d368d 100644
--- a/regress/usr.bin/mandoc/roff/nr/int.out_ascii
+++ b/regress/usr.bin/mandoc/roff/nr/int.out_ascii
@@ -7,7 +7,8 @@ NNAAMMEE
 
 DDEESSCCRRIIPPTTIIOONN
        initial contents: 0 0 0
-       final contents: 42 -1 2147483647
+       intermediate contents: 42 -1 2147483647
+       final contents: 23 1 -2147483648
 
 
 
diff --git a/share/man/man7/roff.7 b/share/man/man7/roff.7
index 527a6923961..e8d10a5efb9 100644
--- a/share/man/man7/roff.7
+++ b/share/man/man7/roff.7
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: roff.7,v 1.24 2013/10/22 20:37:54 schwarze Exp $
+.\"	$OpenBSD: roff.7,v 1.25 2013/12/15 21:18:00 schwarze Exp $
 .\"
 .\" Copyright (c) 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
 .\" Copyright (c) 2010, 2011 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: October 22 2013 $
+.Dd $Mdocdate: December 15 2013 $
 .Dt ROFF 7
 .Os
 .Sh NAME
@@ -840,19 +840,22 @@ the name of the request, macro or string to be undefined.
 Currently, it is ignored including its arguments,
 and the number of arguments is not checked.
 .Ss \&nr
-Define a register.
+Define or change a register.
 A register is an arbitrary string value that defines some sort of state,
 which influences parsing and/or formatting.
 Its syntax is as follows:
 .Pp
-.D1 Pf \. Cm \&nr Ar name Ar value
+.D1 Pf \. Cm \&nr Ar name Oo +|- Oc Ns Ar value
 .Pp
 The
 .Ar value
 may, at the moment, only be an integer.
-So far, only the following register
+If it is prefixed by a sign, the register will be 
+incremented or decremented instead of assigned to.
+.Pp
+The following register
 .Ar name
-is recognised:
+is handled specially:
 .Bl -tag -width Ds
 .It Cm nS
 If set to a positive integer value, certain
diff --git a/usr.bin/mandoc/libmandoc.h b/usr.bin/mandoc/libmandoc.h
index 302187d965d..9f24af6b95c 100644
--- a/usr.bin/mandoc/libmandoc.h
+++ b/usr.bin/mandoc/libmandoc.h
@@ -1,4 +1,4 @@
-/*	$Id: libmandoc.h,v 1.21 2013/10/03 22:04:08 schwarze Exp $ */
+/*	$Id: libmandoc.h,v 1.22 2013/12/15 21:18:00 schwarze Exp $ */
 /*
  * Copyright (c) 2009, 2010, 2011, 2012 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2013 Ingo Schwarze <schwarze@openbsd.org>
@@ -68,7 +68,7 @@ void		 roff_reset(struct roff *);
 enum rofferr	 roff_parseln(struct roff *, int, 
 			char **, size_t *, int, int *);
 void		 roff_endparse(struct roff *);
-void		 roff_setreg(struct roff *, const char *, int);
+void		 roff_setreg(struct roff *, const char *, int, char sign);
 int		 roff_getreg(const struct roff *, const char *);
 char		*roff_strdup(const struct roff *, const char *);
 int		 roff_getcontrol(const struct roff *, 
diff --git a/usr.bin/mandoc/mdoc_validate.c b/usr.bin/mandoc/mdoc_validate.c
index 2d85c62f0a5..683e6464049 100644
--- a/usr.bin/mandoc/mdoc_validate.c
+++ b/usr.bin/mandoc/mdoc_validate.c
@@ -1,4 +1,4 @@
-/*	$Id: mdoc_validate.c,v 1.115 2013/10/21 23:32:33 schwarze Exp $ */
+/*	$Id: mdoc_validate.c,v 1.116 2013/12/15 21:18:00 schwarze Exp $ */
 /*
  * Copyright (c) 2008-2012 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2010, 2011, 2012, 2013 Ingo Schwarze <schwarze@openbsd.org>
@@ -1987,10 +1987,10 @@ post_sh_head(POST_ARGS)
 	/* The SYNOPSIS gets special attention in other areas. */
 
 	if (SEC_SYNOPSIS == sec) {
-		roff_setreg(mdoc->roff, "nS", 1);
+		roff_setreg(mdoc->roff, "nS", 1, '=');
 		mdoc->flags |= MDOC_SYNOPSIS;
 	} else {
-		roff_setreg(mdoc->roff, "nS", 0);
+		roff_setreg(mdoc->roff, "nS", 0, '=');
 		mdoc->flags &= ~MDOC_SYNOPSIS;
 	}
 
diff --git a/usr.bin/mandoc/roff.c b/usr.bin/mandoc/roff.c
index 2b98bab84a9..6c9dfa97282 100644
--- a/usr.bin/mandoc/roff.c
+++ b/usr.bin/mandoc/roff.c
@@ -1,4 +1,4 @@
-/*	$Id: roff.c,v 1.59 2013/10/22 20:37:54 schwarze Exp $ */
+/*	$Id: roff.c,v 1.60 2013/12/15 21:18:00 schwarze Exp $ */
 /*
  * Copyright (c) 2010, 2011, 2012 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2010, 2011, 2012, 2013 Ingo Schwarze <schwarze@openbsd.org>
@@ -1356,7 +1356,7 @@ roff_ds(ROFF_ARGS)
 }
 
 void
-roff_setreg(struct roff *r, const char *name, int val)
+roff_setreg(struct roff *r, const char *name, int val, char sign)
 {
 	struct roffreg	*reg;
 
@@ -1371,11 +1371,17 @@ roff_setreg(struct roff *r, const char *name, int val)
 		reg = mandoc_malloc(sizeof(struct roffreg));
 		reg->key.p = mandoc_strdup(name);
 		reg->key.sz = strlen(name);
+		reg->val = 0;
 		reg->next = r->regtab;
 		r->regtab = reg;
 	}
 
-	reg->val = val;
+	if ('+' == sign)
+		reg->val += val;
+	else if ('-' == sign)
+		reg->val -= val;
+	else
+		reg->val = val;
 }
 
 int
@@ -1422,14 +1428,21 @@ roff_nr(ROFF_ARGS)
 {
 	const char	*key;
 	char		*val;
+	size_t		 sz;
 	int		 iv;
+	char		 sign;
 
 	val = *bufp + pos;
 	key = roff_getname(r, &val, ln, pos);
 
-	iv = mandoc_strntoi(val, strlen(val), 10);
+	sign = *val;
+	if ('+' == sign || '-' == sign)
+		val++;
+
+	sz = strspn(val, "0123456789");
+	iv = sz ? mandoc_strntoi(val, sz, 10) : 0;
 
-	roff_setreg(r, key, iv);
+	roff_setreg(r, key, iv, sign);
 
 	return(ROFF_IGN);
 }