When accessing an undefined number register, define it to be zero, like

the previous commit for strings and macros, only technically simpler.
Desired behaviour also mentioned by Werner Lemberg in 2011.
This diff adds functionality but is -21 +19 LOC.  :-)

5 files changed, 68 insertions, 27 deletions

diff --git a/libmandoc.h b/libmandoc.h
index 2cf07628..9cc8cce4 100644
--- a/libmandoc.h
+++ b/libmandoc.h
@@ -1,4 +1,4 @@
-/*	$Id: libmandoc.h,v 1.70 2017/07/08 17:52:49 schwarze Exp $ */
+/*	$Id: libmandoc.h,v 1.71 2018/04/09 22:27:04 schwarze Exp $ */
 /*
  * Copyright (c) 2009, 2010, 2011, 2012 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2013, 2014, 2015, 2017 Ingo Schwarze <schwarze@openbsd.org>
@@ -66,7 +66,7 @@ void		 roff_man_reset(struct roff_man *);
 enum rofferr	 roff_parseln(struct roff *, int, struct buf *, int *);
 void		 roff_endparse(struct roff *);
 void		 roff_setreg(struct roff *, const char *, int, char sign);
-int		 roff_getreg(const struct roff *, const char *);
+int		 roff_getreg(struct roff *, const char *);
 char		*roff_strdup(const struct roff *, const char *);
 int		 roff_getcontrol(const struct roff *,
 			const char *, int *);
diff --git a/regress/roff/nr/Makefile b/regress/roff/nr/Makefile
index 8da68878..b3ba8102 100644
--- a/regress/roff/nr/Makefile
+++ b/regress/roff/nr/Makefile
@@ -1,6 +1,6 @@
 # $OpenBSD: Makefile,v 1.9 2015/01/23 00:38:43 schwarze Exp $
 
-REGRESS_TARGETS = argc divzero eval escname int predef rr scale
+REGRESS_TARGETS = argc divzero escname eval int predef rr scale undef
 LINT_TARGETS	= divzero escname
 
 .include <bsd.regress.mk>
diff --git a/regress/roff/nr/undef.in b/regress/roff/nr/undef.in
new file mode 100644
index 00000000..fd6000cb
--- /dev/null
+++ b/regress/roff/nr/undef.in
@@ -0,0 +1,24 @@
+.\" $OpenBSD: divzero.in,v 1.3 2017/07/04 14:53:27 schwarze Exp $
+.TH NR-UNDEF 1 "April 9, 2018"
+.SH NAME
+nr-undef \- using an undefined number register
+.SH DESCRIPTION
+The myr register is initially
+.ie rmyr defined.
+.el undefined.
+.PP
+Its initial value is \n[myr].
+.PP
+After interpolating it, is is now
+.ie rmyr defined.
+.el undefined.
+.PP
+.nr myr 1
+After defining it to \n[myr], it is of course still
+.ie rmyr defined.
+.el undefined.
+.PP
+.rr myr
+After removing it, it is again
+.ie rmyr defined.
+.el undefined.
diff --git a/regress/roff/nr/undef.out_ascii b/regress/roff/nr/undef.out_ascii
new file mode 100644
index 00000000..e7649eca
--- /dev/null
+++ b/regress/roff/nr/undef.out_ascii
@@ -0,0 +1,21 @@
+NR-UNDEF(1)                 General Commands Manual                NR-UNDEF(1)
+
+
+
+NNAAMMEE
+       nr-undef - using an undefined number register
+
+DDEESSCCRRIIPPTTIIOONN
+       The myr register is initially undefined.
+
+       Its initial value is 0.
+
+       After interpolating it, is is now defined.
+
+       After defining it to 1, it is of course still defined.
+
+       After removing it, it is again undefined.
+
+
+
+OpenBSD                          April 9, 2018                     NR-UNDEF(1)
diff --git a/roff.c b/roff.c
index 2a609eaf..08c0afc5 100644
--- a/roff.c
+++ b/roff.c
@@ -1,4 +1,4 @@
-/*	$Id: roff.c,v 1.325 2018/04/09 02:31:42 schwarze Exp $ */
+/*	$Id: roff.c,v 1.326 2018/04/09 22:27:04 schwarze Exp $ */
 /*
  * Copyright (c) 2008-2012, 2014 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2010-2015, 2017, 2018 Ingo Schwarze <schwarze@openbsd.org>
@@ -182,8 +182,7 @@ static	void		 roff_freestr(struct roffkv *);
 static	size_t		 roff_getname(struct roff *, char **, int, int);
 static	int		 roff_getnum(const char *, int *, int *, int);
 static	int		 roff_getop(const char *, int *, char *);
-static	int		 roff_getregn(const struct roff *,
-				const char *, size_t);
+static	int		 roff_getregn(struct roff *, const char *, size_t);
 static	int		 roff_getregro(const struct roff *,
 				const char *name);
 static	const char	*roff_getstrn(struct roff *,
@@ -207,6 +206,8 @@ static	enum rofferr	 roff_res(struct roff *, struct buf *, int, int);
 static	enum rofferr	 roff_rm(ROFF_ARGS);
 static	enum rofferr	 roff_rn(ROFF_ARGS);
 static	enum rofferr	 roff_rr(ROFF_ARGS);
+static	void		 roff_setregn(struct roff *, const char *,
+				size_t, int, char);
 static	void		 roff_setstr(struct roff *,
 				const char *, const char *, int);
 static	void		 roff_setstrn(struct roffkv **, const char *,
@@ -2521,19 +2522,27 @@ roff_evalnum(struct roff *r, int ln, const char *v,
 void
 roff_setreg(struct roff *r, const char *name, int val, char sign)
 {
+	roff_setregn(r, name, strlen(name), val, sign);
+}
+
+static void
+roff_setregn(struct roff *r, const char *name, size_t len,
+    int val, char sign)
+{
 	struct roffreg	*reg;
 
 	/* Search for an existing register with the same name. */
 	reg = r->regtab;
 
-	while (reg && strcmp(name, reg->key.p))
+	while (reg != NULL && (reg->key.sz != len ||
+	    strncmp(reg->key.p, name, len) != 0))
 		reg = reg->next;
 
 	if (NULL == reg) {
 		/* Create a new register. */
 		reg = mandoc_malloc(sizeof(struct roffreg));
-		reg->key.p = mandoc_strdup(name);
-		reg->key.sz = strlen(name);
+		reg->key.p = mandoc_strndup(name, len);
+		reg->key.sz = len;
 		reg->val = 0;
 		reg->next = r->regtab;
 		r->regtab = reg;
@@ -2578,26 +2587,13 @@ roff_getregro(const struct roff *r, const char *name)
 }
 
 int
-roff_getreg(const struct roff *r, const char *name)
+roff_getreg(struct roff *r, const char *name)
 {
-	struct roffreg	*reg;
-	int		 val;
-
-	if ('.' == name[0] && '\0' != name[1] && '\0' == name[2]) {
-		val = roff_getregro(r, name + 1);
-		if (-1 != val)
-			return val;
-	}
-
-	for (reg = r->regtab; reg; reg = reg->next)
-		if (0 == strcmp(name, reg->key.p))
-			return reg->val;
-
-	return 0;
+	return roff_getregn(r, name, strlen(name));
 }
 
 static int
-roff_getregn(const struct roff *r, const char *name, size_t len)
+roff_getregn(struct roff *r, const char *name, size_t len)
 {
 	struct roffreg	*reg;
 	int		 val;
@@ -2613,6 +2609,7 @@ roff_getregn(const struct roff *r, const char *name, size_t len)
 		    0 == strncmp(name, reg->key.p, len))
 			return reg->val;
 
+	roff_setregn(r, name, len, 0, '\0');
 	return 0;
 }
 
@@ -2664,14 +2661,13 @@ roff_nr(ROFF_ARGS)
 	keysz = roff_getname(r, &val, ln, pos);
 	if (key[keysz] == '\\')
 		return ROFF_IGN;
-	key[keysz] = '\0';
 
 	sign = *val;
 	if (sign == '+' || sign == '-')
 		val++;
 
 	if (roff_evalnum(r, ln, val, NULL, &iv, ROFFNUM_SCALE))
-		roff_setreg(r, key, iv, sign);
+		roff_setregn(r, key, keysz, iv, sign);
 
 	return ROFF_IGN;
 }