===================================================================
RCS file: /cvs/mandoc/roff.c,v
retrieving revision 1.179
retrieving revision 1.199
diff -u -p -r1.179 -r1.199
--- mandoc/roff.c	2013/10/05 20:30:05	1.179
+++ mandoc/roff.c	2014/03/19 21:51:20	1.199
@@ -1,7 +1,7 @@
-/*	$Id: roff.c,v 1.179 2013/10/05 20:30:05 schwarze Exp $ */
+/*	$Id: roff.c,v 1.199 2014/03/19 21:51:20 schwarze Exp $ */
 /*
  * Copyright (c) 2010, 2011, 2012 Kristaps Dzonsons <kristaps@bsd.lv>
- * Copyright (c) 2010, 2011, 2012, 2013 Ingo Schwarze <schwarze@openbsd.org>
+ * Copyright (c) 2010-2014 Ingo Schwarze <schwarze@openbsd.org>
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -40,12 +40,16 @@ enum	rofft {
 	ROFF_am,
 	ROFF_ami,
 	ROFF_am1,
+	ROFF_as,
 	ROFF_cc,
+	ROFF_ce,
 	ROFF_de,
 	ROFF_dei,
 	ROFF_de1,
 	ROFF_ds,
 	ROFF_el,
+	ROFF_fam,
+	ROFF_hw,
 	ROFF_hy,
 	ROFF_ie,
 	ROFF_if,
@@ -68,27 +72,11 @@ enum	rofft {
 	ROFF_EQ,
 	ROFF_EN,
 	ROFF_cblock,
-	ROFF_ccond,
 	ROFF_USERDEF,
 	ROFF_MAX
 };
 
-enum	roffrule {
-	ROFFRULE_ALLOW,
-	ROFFRULE_DENY
-};
-
 /*
- * A single register entity.  If "set" is zero, the value of the
- * register should be the default one, which is per-register.
- * Registers are assumed to be unsigned ints for now.
- */
-struct	reg {
-	int		 set; /* whether set or not */
-	unsigned int	 u; /* unsigned integer */
-};
-
-/*
  * An incredibly-simple string buffer.
  */
 struct	roffstr {
@@ -105,14 +93,23 @@ struct	roffkv {
 	struct roffkv	*next; /* next in list */
 };
 
+/*
+ * A single number register as part of a singly-linked list.
+ */
+struct	roffreg {
+	struct roffstr	 key;
+	int		 val;
+	struct roffreg	*next;
+};
+
 struct	roff {
-	enum mparset	 parsetype; /* requested parse type */
 	struct mparse	*parse; /* parse point */
+	int		 options; /* parse options */
 	struct roffnode	*last; /* leaf of stack */
-	enum roffrule	 rstack[RSTACK_MAX]; /* stack of !`ie' rules */
+	int		 rstack[RSTACK_MAX]; /* stack of !`ie' rules */
 	char		 control; /* control character */
 	int		 rstackpos; /* position in rstack */
-	struct reg	 regs[REG__MAX];
+	struct roffreg	*regtab; /* number registers */
 	struct roffkv	*strtab; /* user-defined strings & macros */
 	struct roffkv	*xmbtab; /* multi-byte trans table (`tr') */
 	struct roffstr	*xtab; /* single-byte trans table (`tr') */
@@ -133,7 +130,7 @@ struct	roffnode {
 	char		*name; /* node name, e.g. macro name */
 	char		*end; /* end-rules: custom token */
 	int		 endspan; /* end-rules: next-line or infty */
-	enum roffrule	 rule; /* current evaluation rule */
+	int		 rule; /* current evaluation rule */
 };
 
 #define	ROFF_ARGS	 struct roff *r, /* parse ctx */ \
@@ -176,15 +173,22 @@ static	enum rofferr	 roff_block_text(ROFF_ARGS);
 static	enum rofferr	 roff_block_sub(ROFF_ARGS);
 static	enum rofferr	 roff_cblock(ROFF_ARGS);
 static	enum rofferr	 roff_cc(ROFF_ARGS);
-static	enum rofferr	 roff_ccond(ROFF_ARGS);
+static	void		 roff_ccond(struct roff *, int, int);
 static	enum rofferr	 roff_cond(ROFF_ARGS);
 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 roffrule	 roff_evalcond(const char *, int *);
+static	int		 roff_evalcond(const char *, int *);
+static	int		 roff_evalstrcond(const char *, int *);
 static	void		 roff_free1(struct roff *);
+static	void		 roff_freereg(struct roffreg *);
 static	void		 roff_freestr(struct roffkv *);
 static	char		*roff_getname(struct roff *, char **, int, int);
+static	int		 roff_getnum(const char *, int *, int *);
+static	int		 roff_getop(const char *, int *, char *);
+static	int		 roff_getregn(const struct roff *,
+				const char *, size_t);
+static	int		 roff_getregro(const char *name);
 static	const char	*roff_getstrn(const struct roff *, 
 				const char *, size_t);
 static	enum rofferr	 roff_it(ROFF_ARGS);
@@ -225,12 +229,16 @@ static	struct roffmac	 roffs[ROFF_MAX] = {
 	{ "am", roff_block, roff_block_text, roff_block_sub, 0, NULL },
 	{ "ami", roff_block, roff_block_text, roff_block_sub, 0, NULL },
 	{ "am1", roff_block, roff_block_text, roff_block_sub, 0, NULL },
+	{ "as", roff_ds, NULL, NULL, 0, NULL },
 	{ "cc", roff_cc, NULL, NULL, 0, NULL },
+	{ "ce", roff_line_ignore, NULL, NULL, 0, NULL },
 	{ "de", roff_block, roff_block_text, roff_block_sub, 0, NULL },
 	{ "dei", roff_block, roff_block_text, roff_block_sub, 0, NULL },
 	{ "de1", roff_block, roff_block_text, roff_block_sub, 0, NULL },
 	{ "ds", roff_ds, NULL, NULL, 0, NULL },
 	{ "el", roff_cond, roff_cond_text, roff_cond_sub, ROFFMAC_STRUCT, NULL },
+	{ "fam", roff_line_ignore, NULL, NULL, 0, NULL },
+	{ "hw", roff_line_ignore, NULL, NULL, 0, NULL },
 	{ "hy", roff_line_ignore, NULL, NULL, 0, NULL },
 	{ "ie", roff_cond, roff_cond_text, roff_cond_sub, ROFFMAC_STRUCT, NULL },
 	{ "if", roff_cond, roff_cond_text, roff_cond_sub, ROFFMAC_STRUCT, NULL },
@@ -253,7 +261,6 @@ static	struct roffmac	 roffs[ROFF_MAX] = {
 	{ "EQ", roff_EQ, NULL, NULL, 0, NULL },
 	{ "EN", roff_EN, NULL, NULL, 0, NULL },
 	{ ".", roff_cblock, NULL, NULL, 0, NULL },
-	{ "\\}", roff_ccond, NULL, NULL, 0, NULL },
 	{ NULL, roff_userdef, NULL, NULL, 0, NULL },
 };
 
@@ -389,7 +396,7 @@ roffnode_push(struct roff *r, enum rofft tok, const ch
 	p->parent = r->last;
 	p->line = line;
 	p->col = col;
-	p->rule = p->parent ? p->parent->rule : ROFFRULE_DENY;
+	p->rule = p->parent ? p->parent->rule : 0;
 
 	r->last = p;
 }
@@ -424,6 +431,10 @@ roff_free1(struct roff *r)
 
 	r->strtab = r->xmbtab = NULL;
 
+	roff_freereg(r->regtab);
+
+	r->regtab = NULL;
+
 	if (r->xtab)
 		for (i = 0; i < 128; i++)
 			free(r->xtab[i].p);
@@ -435,15 +446,9 @@ roff_free1(struct roff *r)
 void
 roff_reset(struct roff *r)
 {
-	int		 i;
 
 	roff_free1(r);
-
 	r->control = 0;
-	memset(&r->regs, 0, sizeof(struct reg) * REG__MAX);
-
-	for (i = 0; i < PREDEFS_MAX; i++) 
-		roff_setstr(r, predefs[i].name, predefs[i].str, 0);
 }
 
 
@@ -457,41 +462,38 @@ roff_free(struct roff *r)
 
 
 struct roff *
-roff_alloc(enum mparset type, struct mparse *parse)
+roff_alloc(struct mparse *parse, int options)
 {
 	struct roff	*r;
-	int		 i;
 
 	r = mandoc_calloc(1, sizeof(struct roff));
-	r->parsetype = type;
 	r->parse = parse;
+	r->options = options;
 	r->rstackpos = -1;
 	
 	roffhash_init();
 
-	for (i = 0; i < PREDEFS_MAX; i++) 
-		roff_setstr(r, predefs[i].name, predefs[i].str, 0);
-
 	return(r);
 }
 
 /*
- * Pre-filter each and every line for reserved words (one beginning with
- * `\*', e.g., `\*(ab').  These must be handled before the actual line
- * is processed. 
- * This also checks the syntax of regular escapes.
+ * In the current line, expand user-defined strings ("\*")
+ * and references to number registers ("\n").
+ * Also check the syntax of other escape sequences.
  */
 static enum rofferr
 roff_res(struct roff *r, char **bufp, size_t *szp, int ln, int pos)
 {
-	enum mandoc_esc	 esc;
+	char		 ubuf[12]; /* buffer to print the number */
 	const char	*stesc;	/* start of an escape sequence ('\\') */
 	const char	*stnam;	/* start of the name, after "[(*" */
 	const char	*cp;	/* end of the name, e.g. before ']' */
 	const char	*res;	/* the string to be substituted */
-	int		 i, maxl, expand_count;
-	size_t		 nsz;
-	char		*n;
+	char		*nbuf;	/* new buffer to copy bufp to */
+	size_t		 nsz;	/* size of the new buffer */
+	size_t		 maxl;  /* expected length of the escape name */
+	size_t		 naml;	/* actual length of the escape name */
+	int		 expand_count;	/* to avoid infinite loops */
 
 	expand_count = 0;
 
@@ -501,7 +503,7 @@ again:
 		stesc = cp++;
 
 		/*
-		 * The second character must be an asterisk.
+		 * The second character must be an asterisk or an n.
 		 * If it isn't, skip it anyway:  It is escaped,
 		 * so it can't start another escape sequence.
 		 */
@@ -509,12 +511,16 @@ again:
 		if ('\0' == *cp)
 			return(ROFF_CONT);
 
-		if ('*' != *cp) {
-			res = cp;
-			esc = mandoc_escape(&cp, NULL, NULL);
-			if (ESCAPE_ERROR != esc)
+		switch (*cp) {
+		case ('*'):
+			res = NULL;
+			break;
+		case ('n'):
+			res = ubuf;
+			break;
+		default:
+			if (ESCAPE_ERROR != mandoc_escape(&cp, NULL, NULL))
 				continue;
-			cp = res;
 			mandoc_msg
 				(MANDOCERR_BADESCAPE, r->parse, 
 				 ln, (int)(stesc - *bufp), NULL);
@@ -525,7 +531,7 @@ again:
 
 		/*
 		 * The third character decides the length
-		 * of the name of the string.
+		 * of the name of the string or register.
 		 * Save a pointer to the name.
 		 */
 
@@ -548,7 +554,7 @@ again:
 
 		/* Advance to the end of the name. */
 
-		for (i = 0; 0 == maxl || i < maxl; i++, cp++) {
+		for (naml = 0; 0 == maxl || naml < maxl; naml++, cp++) {
 			if ('\0' == *cp) {
 				mandoc_msg
 					(MANDOCERR_BADESCAPE, 
@@ -565,7 +571,11 @@ again:
 		 * undefined, resume searching for escapes.
 		 */
 
-		res = roff_getstrn(r, stnam, (size_t)i);
+		if (NULL == res)
+			res = roff_getstrn(r, stnam, naml);
+		else
+			snprintf(ubuf, sizeof(ubuf), "%d",
+			    roff_getregn(r, stnam, naml));
 
 		if (NULL == res) {
 			mandoc_msg
@@ -579,15 +589,15 @@ again:
 		pos = stesc - *bufp;
 
 		nsz = *szp + strlen(res) + 1;
-		n = mandoc_malloc(nsz);
+		nbuf = mandoc_malloc(nsz);
 
-		strlcpy(n, *bufp, (size_t)(stesc - *bufp + 1));
-		strlcat(n, res, nsz);
-		strlcat(n, cp + (maxl ? 0 : 1), nsz);
+		strlcpy(nbuf, *bufp, (size_t)(stesc - *bufp + 1));
+		strlcat(nbuf, res, nsz);
+		strlcat(nbuf, cp + (maxl ? 0 : 1), nsz);
 
 		free(*bufp);
 
-		*bufp = n;
+		*bufp = nbuf;
 		*szp = nsz;
 
 		if (EXPAND_LIMIT >= ++expand_count)
@@ -626,8 +636,7 @@ roff_parsetext(char **bufp, size_t *szp, int pos, int 
 		if ('\\' == *p) {
 			/* Skip over escapes. */
 			p++;
-			esc = mandoc_escape
-				((const char const **)&p, NULL, NULL);
+			esc = mandoc_escape((const char **)&p, NULL, NULL);
 			if (ESCAPE_ERROR == esc)
 				break;
 			continue;
@@ -698,19 +707,14 @@ roff_parseln(struct roff *r, int ln, char **bufp, 
 		assert(ROFF_IGN == e || ROFF_CONT == e);
 		if (ROFF_CONT != e)
 			return(e);
-		if (r->eqn)
-			return(eqn_read(&r->eqn, ln, *bufp, pos, offs));
+	}
+	if (r->eqn)
+		return(eqn_read(&r->eqn, ln, *bufp, ppos, offs));
+	if ( ! ctl) {
 		if (r->tbl)
 			return(tbl_read(r->tbl, ln, *bufp, pos));
 		return(roff_parsetext(bufp, szp, pos, offs));
-	} else if ( ! ctl) {
-		if (r->eqn)
-			return(eqn_read(&r->eqn, ln, *bufp, pos, offs));
-		if (r->tbl)
-			return(tbl_read(r->tbl, ln, *bufp, pos));
-		return(roff_parsetext(bufp, szp, pos, offs));
-	} else if (r->eqn)
-		return(eqn_read(&r->eqn, ln, *bufp, ppos, offs));
+	}
 
 	/*
 	 * If a scope is open, go to the child handler for that macro,
@@ -778,14 +782,10 @@ roff_parse(struct roff *r, const char *buf, int *pos)
 			'\t' == buf[*pos] || ' ' == buf[*pos])
 		return(ROFF_MAX);
 
-	/*
-	 * We stop the macro parse at an escape, tab, space, or nil.
-	 * However, `\}' is also a valid macro, so make sure we don't
-	 * clobber it by seeing the `\' as the end of token.
-	 */
+	/* We stop the macro parse at an escape, tab, space, or nil. */
 
 	mac = buf + *pos;
-	maclen = strcspn(mac + 1, " \\\t\0") + 1;
+	maclen = strcspn(mac, " \\\t\0");
 
 	t = (r->current_string = roff_getstrn(r, mac, maclen))
 	    ? ROFF_USERDEF : roffhash_find(mac, maclen);
@@ -854,14 +854,13 @@ roffnode_cleanscope(struct roff *r)
 }
 
 
-/* ARGSUSED */
-static enum rofferr
-roff_ccond(ROFF_ARGS)
+static void
+roff_ccond(struct roff *r, int ln, int ppos)
 {
 
 	if (NULL == r->last) {
 		mandoc_msg(MANDOCERR_NOSCOPE, r->parse, ln, ppos, NULL);
-		return(ROFF_IGN);
+		return;
 	}
 
 	switch (r->last->tok) {
@@ -873,20 +872,17 @@ roff_ccond(ROFF_ARGS)
 		break;
 	default:
 		mandoc_msg(MANDOCERR_NOSCOPE, r->parse, ln, ppos, NULL);
-		return(ROFF_IGN);
+		return;
 	}
 
 	if (r->last->endspan > -1) {
 		mandoc_msg(MANDOCERR_NOSCOPE, r->parse, ln, ppos, NULL);
-		return(ROFF_IGN);
+		return;
 	}
 
-	if ((*bufp)[pos])
-		mandoc_msg(MANDOCERR_ARGSLOST, r->parse, ln, pos, NULL);
-
 	roffnode_pop(r);
 	roffnode_cleanscope(r);
-	return(ROFF_IGN);
+	return;
 }
 
 
@@ -931,7 +927,7 @@ roff_block(ROFF_ARGS)
 	/*
 	 * At the beginning of a `de' macro, clear the existing string
 	 * with the same name, if there is one.  New content will be
-	 * added from roff_block_text() in multiline mode.
+	 * appended from roff_block_text() in multiline mode.
 	 */
 
 	if (ROFF_de == tok)
@@ -1021,7 +1017,7 @@ roff_block_sub(ROFF_ARGS)
 	 */
 	if (ROFF_cblock != t) {
 		if (ROFF_de == tok)
-			roff_setstr(r, r->last->name, *bufp + ppos, 1);
+			roff_setstr(r, r->last->name, *bufp + ppos, 2);
 		return(ROFF_IGN);
 	}
 
@@ -1037,7 +1033,7 @@ roff_block_text(ROFF_ARGS)
 {
 
 	if (ROFF_de == tok)
-		roff_setstr(r, r->last->name, *bufp + pos, 1);
+		roff_setstr(r, r->last->name, *bufp + pos, 2);
 
 	return(ROFF_IGN);
 }
@@ -1048,8 +1044,8 @@ static enum rofferr
 roff_cond_sub(ROFF_ARGS)
 {
 	enum rofft	 t;
-	enum roffrule	 rr;
 	char		*ep;
+	int		 rr;
 
 	rr = r->last->rule;
 	roffnode_cleanscope(r);
@@ -1061,37 +1057,31 @@ roff_cond_sub(ROFF_ARGS)
 	 */
 
 	if ((ROFF_MAX != t) &&
-	    (ROFF_ccond == t || ROFFRULE_ALLOW == rr ||
-	     ROFFMAC_STRUCT & roffs[t].flags)) {
+	    (rr || ROFFMAC_STRUCT & roffs[t].flags)) {
 		assert(roffs[t].proc);
 		return((*roffs[t].proc)(r, t, bufp, szp,
 					ln, ppos, pos, offs));
 	}
 
-	/* Always check for the closing delimiter `\}'. */
+	/*
+	 * If `\}' occurs on a macro line without a preceding macro,
+	 * drop the line completely.
+	 */
 
-	ep = &(*bufp)[pos];
-	while (NULL != (ep = strchr(ep, '\\'))) {
-		if ('}' != *(++ep))
-			continue;
+	ep = *bufp + pos;
+	if ('\\' == ep[0] && '}' == ep[1])
+		rr = 0;
 
-		/*
-		 * If we're at the end of line, then just chop
-		 * off the \} and resize the buffer.
-		 * If we aren't, then convert it to spaces.
-		 */
+	/* Always check for the closing delimiter `\}'. */
 
-		if ('\0' == *(ep + 1)) {
-			*--ep = '\0';
-			*szp -= 2;
-		} else
-			*(ep - 1) = *ep = ' ';
-
-		roff_ccond(r, ROFF_ccond, bufp, szp, 
-				ln, pos, pos + 2, offs);
-		break;
+	while (NULL != (ep = strchr(ep, '\\'))) {
+		if ('}' == *(++ep)) {
+			*ep = '&';
+			roff_ccond(r, ln, ep - *bufp - 1);
+		}
+		++ep;
 	}
-	return(ROFFRULE_DENY == rr ? ROFF_IGN : ROFF_CONT);
+	return(rr ? ROFF_CONT : ROFF_IGN);
 }
 
 /* ARGSUSED */
@@ -1099,45 +1089,169 @@ static enum rofferr
 roff_cond_text(ROFF_ARGS)
 {
 	char		*ep;
-	enum roffrule	 rr;
+	int		 rr;
 
 	rr = r->last->rule;
 	roffnode_cleanscope(r);
 
-	ep = &(*bufp)[pos];
-	for ( ; NULL != (ep = strchr(ep, '\\')); ep++) {
-		ep++;
-		if ('}' != *ep)
-			continue;
-		*ep = '&';
-		roff_ccond(r, ROFF_ccond, bufp, szp, 
-				ln, pos, pos + 2, offs);
+	ep = *bufp + pos;
+	while (NULL != (ep = strchr(ep, '\\'))) {
+		if ('}' == *(++ep)) {
+			*ep = '&';
+			roff_ccond(r, ln, ep - *bufp - 1);
+		}
+		++ep;
 	}
-	return(ROFFRULE_DENY == rr ? ROFF_IGN : ROFF_CONT);
+	return(rr ? ROFF_CONT : ROFF_IGN);
 }
 
-static enum roffrule
+static int
+roff_getnum(const char *v, int *pos, int *res)
+{
+	int p, n;
+
+	p = *pos;
+	n = v[p] == '-';
+	if (n)
+		p++;
+
+	for (*res = 0; isdigit((unsigned char)v[p]); p++)
+		*res += 10 * *res + v[p] - '0';
+	if (p == *pos + n)
+		return 0;
+
+	if (n)
+		*res = -*res;
+
+	*pos = p;
+	return 1;
+}
+
+static int
+roff_getop(const char *v, int *pos, char *res)
+{
+	int e;
+
+	*res = v[*pos];
+	e = v[*pos + 1] == '=';
+
+	switch (*res) {
+	case '=':
+		break;
+	case '>':
+		if (e)
+			*res = 'g';
+		break;
+	case '<':
+		if (e)
+			*res = 'l';
+		break;
+	default:
+		return(0);
+	}
+
+	*pos += 1 + e;
+
+	return(*res);
+}
+
+/*
+ * Evaluate a string comparison condition.
+ * The first character is the delimiter.
+ * Succeed if the string up to its second occurrence
+ * matches the string up to its third occurence.
+ * Advance the cursor after the third occurrence
+ * or lacking that, to the end of the line.
+ */
+static int
+roff_evalstrcond(const char *v, int *pos)
+{
+	const char	*s1, *s2, *s3;
+	int		 match;
+
+	match = 0;
+	s1 = v + *pos;		/* initial delimiter */
+	s2 = s1 + 1;		/* for scanning the first string */
+	s3 = strchr(s2, *s1);	/* for scanning the second string */
+
+	if (NULL == s3)		/* found no middle delimiter */
+		goto out;
+
+	while ('\0' != *++s3) {
+		if (*s2 != *s3) {  /* mismatch */
+			s3 = strchr(s3, *s1);
+			break;
+		}
+		if (*s3 == *s1) {  /* found the final delimiter */
+			match = 1;
+			break;
+		}
+		s2++;
+	}
+
+out:
+	if (NULL == s3)
+		s3 = strchr(s2, '\0');
+	else
+		s3++;
+	*pos = s3 - v;
+	return(match);
+}
+
+static int
 roff_evalcond(const char *v, int *pos)
 {
+	int	 wanttrue, lh, rh;
+	char	 op;
 
+	if ('!' == v[*pos]) {
+		wanttrue = 0;
+		(*pos)++;
+	} else
+		wanttrue = 1;
+
 	switch (v[*pos]) {
 	case ('n'):
+		/* FALLTHROUGH */
+	case ('o'):
 		(*pos)++;
-		return(ROFFRULE_ALLOW);
+		return(wanttrue);
+	case ('c'):
+		/* FALLTHROUGH */
+	case ('d'):
+		/* FALLTHROUGH */
 	case ('e'):
 		/* FALLTHROUGH */
-	case ('o'):
+	case ('r'):
 		/* FALLTHROUGH */
 	case ('t'):
 		(*pos)++;
-		return(ROFFRULE_DENY);
+		return(!wanttrue);
 	default:
 		break;
 	}
 
-	while (v[*pos] && ' ' != v[*pos])
-		(*pos)++;
-	return(ROFFRULE_DENY);
+	if (!roff_getnum(v, pos, &lh))
+		return(roff_evalstrcond(v, pos) == wanttrue);
+	if (!roff_getop(v, pos, &op))
+		return((lh > 0) == wanttrue);
+	if (!roff_getnum(v, pos, &rh))
+		return(0);
+
+	switch (op) {
+	case 'g':
+		return((lh >= rh) == wanttrue);
+	case 'l':
+		return((lh <= rh) == wanttrue);
+	case '=':
+		return((lh == rh) == wanttrue);
+	case '>':
+		return((lh > rh) == wanttrue);
+	case '<':
+		return((lh < rh) == wanttrue);
+	default:
+		return(0);
+	}
 }
 
 /* ARGSUSED */
@@ -1164,8 +1278,7 @@ roff_cond(ROFF_ARGS)
 	 */
 
 	r->last->rule = ROFF_el == tok ?
-		(r->rstackpos < 0 ? 
-		 ROFFRULE_DENY : r->rstack[r->rstackpos--]) :
+		(r->rstackpos < 0 ? 0 : r->rstack[r->rstackpos--]) :
 		roff_evalcond(*bufp, &pos);
 
 	/*
@@ -1179,15 +1292,13 @@ roff_cond(ROFF_ARGS)
 				r->parse, ln, ppos, NULL);
 			return(ROFF_ERR);
 		}
-		r->rstack[++r->rstackpos] = 
-			ROFFRULE_DENY == r->last->rule ?
-			ROFFRULE_ALLOW : ROFFRULE_DENY;
+		r->rstack[++r->rstackpos] = !r->last->rule;
 	}
 
 	/* If the parent has false as its rule, then so do we. */
 
-	if (r->last->parent && ROFFRULE_DENY == r->last->parent->rule)
-		r->last->rule = ROFFRULE_DENY;
+	if (r->last->parent && !r->last->parent->rule)
+		r->last->rule = 0;
 
 	/*
 	 * Determine scope.
@@ -1254,29 +1365,117 @@ roff_ds(ROFF_ARGS)
 		string++;
 
 	/* The rest is the value. */
-	roff_setstr(r, name, string, 0);
+	roff_setstr(r, name, string, ROFF_as == tok);
 	return(ROFF_IGN);
 }
 
+void
+roff_setreg(struct roff *r, const char *name, 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))
+		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->val = 0;
+		reg->next = r->regtab;
+		r->regtab = reg;
+	}
+
+	if ('+' == sign)
+		reg->val += val;
+	else if ('-' == sign)
+		reg->val -= val;
+	else
+		reg->val = val;
+}
+
+/*
+ * Handle some predefined read-only number registers.
+ * For now, return -1 if the requested register is not predefined;
+ * in case a predefined read-only register having the value -1
+ * were to turn up, another special value would have to be chosen.
+ */
+static int
+roff_getregro(const char *name)
+{
+
+	switch (*name) {
+	case ('A'):  /* ASCII approximation mode is always off. */
+		return(0);
+	case ('g'):  /* Groff compatibility mode is always on. */
+		return(1);
+	case ('H'):  /* Fixed horizontal resolution. */
+		return (24);
+	case ('j'):  /* Always adjust left margin only. */
+		return(0);
+	case ('T'):  /* Some output device is always defined. */
+		return(1);
+	case ('V'):  /* Fixed vertical resolution. */
+		return (40);
+	default:
+		return (-1);
+	}
+}
+
 int
-roff_regisset(const struct roff *r, enum regs reg)
+roff_getreg(const struct roff *r, const char *name)
 {
+	struct roffreg	*reg;
+	int		 val;
 
-	return(r->regs[(int)reg].set);
+	if ('.' == name[0] && '\0' != name[1] && '\0' == name[2]) {
+		val = roff_getregro(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);
 }
 
-unsigned int
-roff_regget(const struct roff *r, enum regs reg)
+static int
+roff_getregn(const struct roff *r, const char *name, size_t len)
 {
+	struct roffreg	*reg;
+	int		 val;
 
-	return(r->regs[(int)reg].u);
+	if ('.' == name[0] && 2 == len) {
+		val = roff_getregro(name + 1);
+		if (-1 != val)
+			return (val);
+	}
+
+	for (reg = r->regtab; reg; reg = reg->next)
+		if (len == reg->key.sz &&
+		    0 == strncmp(name, reg->key.p, len))
+			return(reg->val);
+
+	return(0);
 }
 
-void
-roff_regunset(struct roff *r, enum regs reg)
+static void
+roff_freereg(struct roffreg *reg)
 {
+	struct roffreg	*old_reg;
 
-	r->regs[(int)reg].set = 0;
+	while (NULL != reg) {
+		free(reg->key.p);
+		old_reg = reg;
+		reg = reg->next;
+		free(old_reg);
+	}
 }
 
 /* ARGSUSED */
@@ -1285,19 +1484,22 @@ 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);
 
-	if (0 == strcmp(key, "nS")) {
-		r->regs[(int)REG_nS].set = 1;
-		if ((iv = mandoc_strntoi(val, strlen(val), 10)) >= 0)
-			r->regs[(int)REG_nS].u = (unsigned)iv;
-		else
-			r->regs[(int)REG_nS].u = 0u;
-	}
+	sign = *val;
+	if ('+' == sign || '-' == sign)
+		val++;
 
+	sz = strspn(val, "0123456789");
+	iv = sz ? mandoc_strntoi(val, sz, 10) : 0;
+
+	roff_setreg(r, key, iv, sign);
+
 	return(ROFF_IGN);
 }
 
@@ -1348,7 +1550,7 @@ roff_Dd(ROFF_ARGS)
 {
 	const char *const	*cp;
 
-	if (MPARSE_MDOC != r->parsetype)
+	if (0 == ((MPARSE_MDOC | MPARSE_QUICK) & r->options))
 		for (cp = __mdoc_reserved; *cp; cp++)
 			roff_setstr(r, *cp, NULL, 0);
 
@@ -1361,7 +1563,7 @@ roff_TH(ROFF_ARGS)
 {
 	const char *const	*cp;
 
-	if (MPARSE_MDOC != r->parsetype)
+	if (0 == (MPARSE_QUICK & r->options))
 		for (cp = __man_reserved; *cp; cp++)
 			roff_setstr(r, *cp, NULL, 0);
 
@@ -1583,7 +1785,7 @@ roff_userdef(ROFF_ARGS)
 
 	/*
 	 * Collect pointers to macro argument strings
-	 * and null-terminate them.
+	 * and NUL-terminate them.
 	 */
 	cp = *bufp + pos;
 	for (i = 0; i < 9; i++)
@@ -1663,22 +1865,23 @@ roff_getname(struct roff *r, char **cpp, int ln, int p
 
 /*
  * Store *string into the user-defined string called *name.
- * In multiline mode, append to an existing entry and append '\n';
- * else replace the existing entry, if there is one.
  * To clear an existing entry, call with (*r, *name, NULL, 0).
+ * append == 0: replace mode
+ * append == 1: single-line append mode
+ * append == 2: multiline append mode, append '\n' after each call
  */
 static void
 roff_setstr(struct roff *r, const char *name, const char *string,
-	int multiline)
+	int append)
 {
 
 	roff_setstrn(&r->strtab, name, strlen(name), string,
-			string ? strlen(string) : 0, multiline);
+			string ? strlen(string) : 0, append);
 }
 
 static void
 roff_setstrn(struct roffkv **r, const char *name, size_t namesz,
-		const char *string, size_t stringsz, int multiline)
+		const char *string, size_t stringsz, int append)
 {
 	struct roffkv	*n;
 	char		*c;
@@ -1700,8 +1903,7 @@ roff_setstrn(struct roffkv **r, const char *name, size
 		n->val.sz = 0;
 		n->next = *r;
 		*r = n;
-	} else if (0 == multiline) {
-		/* In multiline mode, append; else replace. */
+	} else if (0 == append) {
 		free(n->val.p);
 		n->val.p = NULL;
 		n->val.sz = 0;
@@ -1714,7 +1916,7 @@ roff_setstrn(struct roffkv **r, const char *name, size
 	 * One additional byte for the '\n' in multiline mode,
 	 * and one for the terminating '\0'.
 	 */
-	newch = stringsz + (multiline ? 2u : 1u);
+	newch = stringsz + (1 < append ? 2u : 1u);
 
 	if (NULL == n->val.p) {
 		n->val.p = mandoc_malloc(newch);
@@ -1741,7 +1943,7 @@ roff_setstrn(struct roffkv **r, const char *name, size
 	}
 
 	/* Append terminating bytes. */
-	if (multiline)
+	if (1 < append)
 		*c++ = '\n';
 
 	*c = '\0';
@@ -1752,11 +1954,17 @@ static const char *
 roff_getstrn(const struct roff *r, const char *name, size_t len)
 {
 	const struct roffkv *n;
+	int i;
 
 	for (n = r->strtab; n; n = n->next)
 		if (0 == strncmp(name, n->key.p, len) && 
 				'\0' == n->key.p[(int)len])
 			return(n->val.p);
+
+	for (i = 0; i < PREDEFS_MAX; i++)
+		if (0 == strncmp(name, predefs[i].name, len) &&
+				'\0' == predefs[i].name[(int)len])
+			return(predefs[i].str);
 
 	return(NULL);
 }