Introduce the concept of nodes that are semantically transparent:

they are skipped when looking for previous or following high-level
macros.  Examples include roff(7) .ft, .ll, and .ta, mdoc(7) .Sm
and .Tg, and man(7) .DT and .PD.  Use this concept for a variety
of improved decisions in various validators and formatters.

While here,
* remove a few const qualifiers on struct arguments that caused trouble;
* get rid of some more Yoda notation in the vicinity;
* and apply some other stylistic improvements in the vicinity.

I found this class of issues while considering .Tg patches from kn@.

64 files changed, 1156 insertions, 311 deletions

diff --git a/man_html.c b/man_html.c
index af942837..538ff734 100644
--- a/man_html.c
+++ b/man_html.c
@@ -34,7 +34,7 @@
 #include "main.h"
 
 #define	MAN_ARGS	  const struct roff_meta *man, \
-			  const struct roff_node *n, \
+			  struct roff_node *n, \
 			  struct html *h
 
 struct	man_html_act {
@@ -244,7 +244,7 @@ print_man_node(MAN_ARGS)
 		 * Close the list if no further item of the same type
 		 * follows; otherwise, close the item only.
 		 */
-		if (list_continues(n, n->next) == '\0') {
+		if (list_continues(n, roff_node_next(n)) == '\0') {
 			print_tagq(h, t);
 			t = NULL;
 		}
@@ -445,15 +445,17 @@ list_continues(const struct roff_node *n1, const struct roff_node *n2)
 static int
 man_IP_pre(MAN_ARGS)
 {
-	const struct roff_node	*nn;
+	struct roff_node	*nn;
 	const char		*list_class;
 	enum htmltag		 list_elem, body_elem;
 	char			 list_type;
 
 	nn = n->type == ROFFT_BLOCK ? n : n->parent;
-	if ((list_type = list_continues(nn->prev, nn)) == '\0') {
+	list_type = list_continues(roff_node_prev(nn), nn);
+	if (list_type == '\0') {
 		/* Start a new list. */
-		if ((list_type = list_continues(nn, nn->next)) == '\0')
+		list_type = list_continues(nn, roff_node_next(nn));
+		if (list_type == '\0')
 			list_type = ' ';
 		switch (list_type) {
 		case ' ':
diff --git a/man_term.c b/man_term.c
index e25f7c74..2f4c18d8 100644
--- a/man_term.c
+++ b/man_term.c
@@ -64,7 +64,7 @@ static	void		  print_man_head(struct termp *,
 static	void		  print_man_foot(struct termp *,
 				const struct roff_meta *);
 static	void		  print_bvspace(struct termp *,
-				const struct roff_node *, int);
+				struct roff_node *, int);
 
 static	int		  pre_B(DECL_ARGS);
 static	int		  pre_DT(DECL_ARGS);
@@ -205,19 +205,20 @@ terminal_man(void *arg, const struct roff_meta *man)
  * first, print it.
  */
 static void
-print_bvspace(struct termp *p, const struct roff_node *n, int pardist)
+print_bvspace(struct termp *p, struct roff_node *n, int pardist)
 {
-	int	 i;
+	struct roff_node	*nch;
+	int			 i;
 
 	term_newln(p);
 
-	if (n->body != NULL && n->body->child != NULL)
-		if (n->body->child->type == ROFFT_TBL)
-			return;
+	if (n->body != NULL &&
+	    (nch = roff_node_child(n->body)) != NULL &&
+	    nch->type == ROFFT_TBL)
+		return;
 
-	if (n->parent->type == ROFFT_ROOT || n->parent->tok != MAN_RS)
-		if (n->prev == NULL)
-			return;
+	if (n->parent->tok != MAN_RS && roff_node_prev(n) == NULL)
+		return;
 
 	for (i = 0; i < pardist; i++)
 		term_vspace(p);
@@ -683,12 +684,8 @@ pre_SS(DECL_ARGS)
 		 * and after an empty subsection.
 		 */
 
-		do {
-			n = n->prev;
-		} while (n != NULL && n->tok >= MAN_TH &&
-		    man_term_act(n->tok)->flags & MAN_NOTEXT);
-		if (n == NULL || n->type == ROFFT_COMMENT ||
-		    (n->tok == MAN_SS && n->body->child == NULL))
+		if ((n = roff_node_prev(n)) == NULL ||
+		    (n->tok == MAN_SS && roff_node_child(n->body) == NULL))
 			break;
 
 		for (i = 0; i < mt->pardist; i++)
@@ -728,12 +725,8 @@ pre_SH(DECL_ARGS)
 		 * and after an empty section.
 		 */
 
-		do {
-			n = n->prev;
-		} while (n != NULL && n->tok >= MAN_TH &&
-		    man_term_act(n->tok)->flags & MAN_NOTEXT);
-		if (n == NULL || n->type == ROFFT_COMMENT ||
-		    (n->tok == MAN_SH && n->body->child == NULL))
+		if ((n = roff_node_prev(n)) == NULL ||
+		    (n->tok == MAN_SH && roff_node_child(n->body) == NULL))
 			break;
 
 		for (i = 0; i < mt->pardist; i++)
@@ -839,7 +832,7 @@ pre_SY(DECL_ARGS)
 
 	switch (n->type) {
 	case ROFFT_BLOCK:
-		if (n->prev == NULL || n->prev->tok != MAN_SY)
+		if ((nn = roff_node_prev(n)) == NULL || nn->tok != MAN_SY)
 			print_bvspace(p, n, mt->pardist);
 		return 1;
 	case ROFFT_HEAD:
diff --git a/mdoc_html.c b/mdoc_html.c
index e1cd8389..bc50720f 100644
--- a/mdoc_html.c
+++ b/mdoc_html.c
@@ -52,8 +52,7 @@ static	void		  print_mdoc_head(const struct roff_meta *,
 				struct html *);
 static	void		  print_mdoc_node(MDOC_ARGS);
 static	void		  print_mdoc_nodelist(MDOC_ARGS);
-static	void		  synopsis_pre(struct html *,
-				const struct roff_node *);
+static	void		  synopsis_pre(struct html *, struct roff_node *);
 
 static	void		  mdoc_root_post(const struct roff_meta *,
 				struct html *);
@@ -250,13 +249,15 @@ static const struct mdoc_html_act mdoc_html_acts[MDOC_MAX - MDOC_Dd] = {
  * See the same function in mdoc_term.c for documentation.
  */
 static void
-synopsis_pre(struct html *h, const struct roff_node *n)
+synopsis_pre(struct html *h, struct roff_node *n)
 {
+	struct roff_node *np;
 
-	if (NULL == n->prev || ! (NODE_SYNPRETTY & n->flags))
+	if ((n->flags & NODE_SYNPRETTY) == 0 ||
+	    (np = roff_node_prev(n)) == NULL)
 		return;
 
-	if (n->prev->tok == n->tok &&
+	if (np->tok == n->tok &&
 	    MDOC_Fo != n->tok &&
 	    MDOC_Ft != n->tok &&
 	    MDOC_Fn != n->tok) {
@@ -264,7 +265,7 @@ synopsis_pre(struct html *h, const struct roff_node *n)
 		return;
 	}
 
-	switch (n->prev->tok) {
+	switch (np->tok) {
 	case MDOC_Fd:
 	case MDOC_Fn:
 	case MDOC_Fo:
@@ -625,17 +626,18 @@ mdoc_ss_pre(MDOC_ARGS)
 static int
 mdoc_fl_pre(MDOC_ARGS)
 {
-	char	*id;
+	struct roff_node	*nn;
+	char			*id;
 
 	if ((id = cond_id(n)) != NULL)
 		print_otag(h, TAG_A, "chR", "permalink", id);
 	print_otag(h, TAG_CODE, "ci", "Fl", id);
 
 	print_text(h, "\\-");
-	if (!(n->child == NULL &&
-	    (n->next == NULL ||
-	     n->next->type == ROFFT_TEXT ||
-	     n->next->flags & NODE_LINE)))
+	if (n->child != NULL ||
+	    ((nn = roff_node_next(n)) != NULL &&
+	     nn->type != ROFFT_TEXT &&
+	     (nn->flags & NODE_LINE) == 0))
 		h->flags |= HTML_NOSPACE;
 
 	return 1;
@@ -909,7 +911,7 @@ mdoc_bl_pre(MDOC_ARGS)
 static int
 mdoc_ex_pre(MDOC_ARGS)
 {
-	if (n->prev)
+	if (roff_node_prev(n) != NULL)
 		print_otag(h, TAG_BR, "");
 	return 1;
 }
@@ -986,7 +988,7 @@ mdoc_bd_pre(MDOC_ARGS)
 			continue;
 		if (nn->tok == MDOC_Sh || nn->tok == MDOC_Ss)
 			comp = 1;
-		if (nn->prev != NULL)
+		if (roff_node_prev(nn) != NULL)
 			break;
 	}
 	(void)strlcpy(buf, "Bd", sizeof(buf));
@@ -1098,22 +1100,21 @@ mdoc_fa_pre(MDOC_ARGS)
 		print_otag(h, TAG_VAR, "c", "Fa");
 		return 1;
 	}
-
-	for (nn = n->child; nn; nn = nn->next) {
+	for (nn = n->child; nn != NULL; nn = nn->next) {
 		t = print_otag(h, TAG_VAR, "c", "Fa");
 		print_text(h, nn->string);
 		print_tagq(h, t);
-		if (nn->next) {
+		if (nn->next != NULL) {
 			h->flags |= HTML_NOSPACE;
 			print_text(h, ",");
 		}
 	}
-
-	if (n->child && n->next && n->next->tok == MDOC_Fa) {
+	if (n->child != NULL &&
+	    (nn = roff_node_next(n)) != NULL &&
+	    nn->tok == MDOC_Fa) {
 		h->flags |= HTML_NOSPACE;
 		print_text(h, ",");
 	}
-
 	return 0;
 }
 
@@ -1572,7 +1573,9 @@ mdoc_sy_pre(MDOC_ARGS)
 static int
 mdoc_lb_pre(MDOC_ARGS)
 {
-	if (SEC_LIBRARY == n->sec && NODE_LINE & n->flags && n->prev)
+	if (n->sec == SEC_LIBRARY &&
+	    n->flags & NODE_LINE &&
+	    roff_node_prev(n) != NULL)
 		print_otag(h, TAG_BR, "");
 
 	print_otag(h, TAG_SPAN, "c", "Lb");
@@ -1582,17 +1585,18 @@ mdoc_lb_pre(MDOC_ARGS)
 static int
 mdoc__x_pre(MDOC_ARGS)
 {
-	const char	*cattr;
-	enum htmltag	 t;
+	struct roff_node	*nn;
+	const char		*cattr;
+	enum htmltag		 t;
 
 	t = TAG_SPAN;
 
 	switch (n->tok) {
 	case MDOC__A:
 		cattr = "RsA";
-		if (n->prev && MDOC__A == n->prev->tok)
-			if (NULL == n->next || MDOC__A != n->next->tok)
-				print_text(h, "and");
+		if ((nn = roff_node_prev(n)) != NULL && nn->tok == MDOC__A &&
+		    ((nn = roff_node_next(n)) == NULL || nn->tok != MDOC__A))
+			print_text(h, "and");
 		break;
 	case MDOC__B:
 		t = TAG_I;
@@ -1647,19 +1651,21 @@ mdoc__x_pre(MDOC_ARGS)
 static void
 mdoc__x_post(MDOC_ARGS)
 {
+	struct roff_node *nn;
 
-	if (MDOC__A == n->tok && n->next && MDOC__A == n->next->tok)
-		if (NULL == n->next->next || MDOC__A != n->next->next->tok)
-			if (NULL == n->prev || MDOC__A != n->prev->tok)
-				return;
+	if (n->tok == MDOC__A &&
+	    (nn = roff_node_next(n)) != NULL && nn->tok == MDOC__A &&
+	    ((nn = roff_node_next(nn)) == NULL || nn->tok != MDOC__A) &&
+	    ((nn = roff_node_prev(n)) == NULL || nn->tok != MDOC__A))
+		return;
 
 	/* TODO: %U */
 
-	if (NULL == n->parent || MDOC_Rs != n->parent->tok)
+	if (n->parent == NULL || n->parent->tok != MDOC_Rs)
 		return;
 
 	h->flags |= HTML_NOSPACE;
-	print_text(h, n->next ? "," : ".");
+	print_text(h, roff_node_next(n) ? "," : ".");
 }
 
 static int
diff --git a/mdoc_man.c b/mdoc_man.c
index 8daaedfe..7169b184 100644
--- a/mdoc_man.c
+++ b/mdoc_man.c
@@ -113,7 +113,7 @@ static	int	  pre_sm(DECL_ARGS);
 static	void	  pre_sp(DECL_ARGS);
 static	int	  pre_sect(DECL_ARGS);
 static	int	  pre_sy(DECL_ARGS);
-static	void	  pre_syn(const struct roff_node *);
+static	void	  pre_syn(struct roff_node *);
 static	void	  pre_ta(DECL_ARGS);
 static	int	  pre_vt(DECL_ARGS);
 static	int	  pre_xr(DECL_ARGS);
@@ -650,7 +650,9 @@ print_node(DECL_ARGS)
 	 * Break the line if we were parsed subsequent the current node.
 	 * This makes the page structure be more consistent.
 	 */
-	if (MMAN_spc & outflags && NODE_LINE & n->flags)
+	if (outflags & MMAN_spc &&
+	    n->flags & NODE_LINE &&
+	    !roff_node_transparent(n))
 		outflags |= MMAN_nl;
 
 	act = NULL;
@@ -777,13 +779,20 @@ post_font(DECL_ARGS)
 static void
 post_percent(DECL_ARGS)
 {
+	struct roff_node *np, *nn, *nnn;
 
 	if (mdoc_man_act(n->tok)->pre == pre_em)
 		font_pop();
-	if (n->next) {
-		print_word(",");
-		if (n->prev &&	n->prev->tok == n->tok &&
-				n->next->tok == n->tok)
+
+	if ((nn = roff_node_next(n)) != NULL) {
+		np = roff_node_prev(n);
+		nnn = nn == NULL ? NULL : roff_node_next(nn);
+		if (nn->tok != n->tok ||
+		    (np != NULL && np->tok == n->tok) ||
+		    (nnn != NULL && nnn->tok == n->tok))
+			print_word(",");
+		if (nn->tok == n->tok &&
+		    (nnn == NULL || nnn->tok != n->tok))
 			print_word("and");
 	} else {
 		print_word(".");
@@ -851,13 +860,15 @@ post_sect(DECL_ARGS)
 
 /* See mdoc_term.c, synopsis_pre() for comments. */
 static void
-pre_syn(const struct roff_node *n)
+pre_syn(struct roff_node *n)
 {
+	struct roff_node *np;
 
-	if (NULL == n->prev || ! (NODE_SYNPRETTY & n->flags))
+	if ((n->flags & NODE_SYNPRETTY) == 0 ||
+	    (np = roff_node_prev(n)) == NULL)
 		return;
 
-	if (n->prev->tok == n->tok &&
+	if (np->tok == n->tok &&
 	    MDOC_Ft != n->tok &&
 	    MDOC_Fo != n->tok &&
 	    MDOC_Fn != n->tok) {
@@ -865,7 +876,7 @@ pre_syn(const struct roff_node *n)
 		return;
 	}
 
-	switch (n->prev->tok) {
+	switch (np->tok) {
 	case MDOC_Fd:
 	case MDOC_Fn:
 	case MDOC_Fo:
@@ -941,11 +952,10 @@ static int
 pre_bd(DECL_ARGS)
 {
 	outflags &= ~(MMAN_PP | MMAN_sp | MMAN_br);
-
-	if (DISP_unfilled == n->norm->Bd.type ||
-	    DISP_literal  == n->norm->Bd.type)
+	if (n->norm->Bd.type == DISP_unfilled ||
+	    n->norm->Bd.type == DISP_literal)
 		print_line(".nf", 0);
-	if (0 == n->norm->Bd.comp && NULL != n->parent->prev)
+	if (n->norm->Bd.comp == 0 && roff_node_prev(n->parent) != NULL)
 		outflags |= MMAN_sp;
 	print_offs(n->norm->Bd.offs, 1);
 	return 1;
@@ -977,7 +987,7 @@ post_bd(DECL_ARGS)
 	}
 
 	/* Maybe we are inside an enclosing list? */
-	if (NULL != n->parent->next)
+	if (roff_node_next(n->parent) != NULL)
 		mid_it();
 }
 
@@ -1102,16 +1112,15 @@ post_bl(DECL_ARGS)
 		print_line(".RE", MMAN_nl);
 		assert(Bl_stack_len);
 		Bl_stack_len--;
-		assert(0 == Bl_stack[Bl_stack_len]);
+		assert(Bl_stack[Bl_stack_len] == 0);
 	} else {
 		outflags |= MMAN_PP | MMAN_nl;
 		outflags &= ~(MMAN_sp | MMAN_br);
 	}
 
 	/* Maybe we are inside an enclosing list? */
-	if (NULL != n->parent->next)
+	if (roff_node_next(n->parent) != NULL)
 		mid_it();
-
 }
 
 static void
@@ -1123,7 +1132,6 @@ pre_br(DECL_ARGS)
 static int
 pre_dl(DECL_ARGS)
 {
-
 	print_offs("6n", 0);
 	return 1;
 }
@@ -1131,11 +1139,10 @@ pre_dl(DECL_ARGS)
 static void
 post_dl(DECL_ARGS)
 {
-
 	print_line(".RE", MMAN_nl);
 
 	/* Maybe we are inside an enclosing list? */
-	if (NULL != n->parent->next)
+	if (roff_node_next(n->parent) != NULL)
 		mid_it();
 }
 
@@ -1236,15 +1243,15 @@ pre_fa(DECL_ARGS)
 static void
 post_fa(DECL_ARGS)
 {
+	struct roff_node *nn;
 
-	if (NULL != n->next && MDOC_Fa == n->next->tok)
+	if ((nn = roff_node_next(n)) != NULL && nn->tok == MDOC_Fa)
 		print_word(",");
 }
 
 static int
 pre_fd(DECL_ARGS)
 {
-
 	pre_syn(n);
 	font_push('B');
 	return 1;
@@ -1253,7 +1260,6 @@ pre_fd(DECL_ARGS)
 static void
 post_fd(DECL_ARGS)
 {
-
 	font_pop();
 	outflags |= MMAN_br;
 }
@@ -1261,7 +1267,6 @@ post_fd(DECL_ARGS)
 static int
 pre_fl(DECL_ARGS)
 {
-
 	font_push('B');
 	print_word("\\-");
 	if (n->child != NULL)
@@ -1272,12 +1277,13 @@ pre_fl(DECL_ARGS)
 static void
 post_fl(DECL_ARGS)
 {
+	struct roff_node *nn;
 
 	font_pop();
-	if (!(n->child != NULL ||
-	    n->next == NULL ||
-	    n->next->type == ROFFT_TEXT ||
-	    n->next->flags & NODE_LINE))
+	if (n->child == NULL &&
+	    ((nn = roff_node_next(n)) != NULL &&
+	    nn->type != ROFFT_TEXT &&
+	    (nn->flags & NODE_LINE) == 0))
 		outflags &= ~MMAN_spc;
 }
 
@@ -1420,9 +1426,9 @@ pre_it(DECL_ARGS)
 	case ROFFT_HEAD:
 		outflags |= MMAN_PP | MMAN_nl;
 		bln = n->parent->parent;
-		if (0 == bln->norm->Bl.comp ||
-		    (NULL == n->parent->prev &&
-		     NULL == bln->parent->prev))
+		if (bln->norm->Bl.comp == 0 ||
+		    (n->parent->prev == NULL &&
+		     roff_node_prev(bln->parent) == NULL))
 			outflags |= MMAN_sp;
 		outflags &= ~MMAN_br;
 		switch (bln->norm->Bl.type) {
@@ -1634,17 +1640,22 @@ pre_nm(DECL_ARGS)
 {
 	char	*name;
 
-	if (n->type == ROFFT_BLOCK) {
+	switch (n->type) {
+	case ROFFT_BLOCK:
 		outflags |= MMAN_Bk;
 		pre_syn(n);
-	}
-	if (n->type != ROFFT_ELEM && n->type != ROFFT_HEAD)
 		return 1;
+	case ROFFT_HEAD:
+	case ROFFT_ELEM:
+		break;
+	default:
+		return 1;
+	}
 	name = n->child == NULL ? NULL : n->child->string;
-	if (NULL == name)
+	if (name == NULL)
 		return 0;
 	if (n->type == ROFFT_HEAD) {
-		if (NULL == n->parent->prev)
+		if (roff_node_prev(n->parent) == NULL)
 			outflags |= MMAN_sp;
 		print_block(".HP", 0);
 		printf(" %dn", man_strlen(name) + 1);
diff --git a/mdoc_markdown.c b/mdoc_markdown.c
index 6d7d3552..1bf48342 100644
--- a/mdoc_markdown.c
+++ b/mdoc_markdown.c
@@ -1,6 +1,6 @@
 /*	$Id$ */
 /*
- * Copyright (c) 2017, 2018 Ingo Schwarze <schwarze@openbsd.org>
+ * Copyright (c) 2017, 2018, 2020 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
@@ -310,7 +310,9 @@ md_node(struct roff_node *n)
 
 	if (outflags & MD_nonl)
 		outflags &= ~(MD_nl | MD_sp);
-	else if (outflags & MD_spc && n->flags & NODE_LINE)
+	else if (outflags & MD_spc &&
+	     n->flags & NODE_LINE &&
+	     !roff_node_transparent(n))
 		outflags |= MD_nl;
 
 	act = NULL;
@@ -787,14 +789,17 @@ md_post_word(struct roff_node *n)
 static void
 md_post_pc(struct roff_node *n)
 {
+	struct roff_node *nn;
+
 	md_post_raw(n);
 	if (n->parent->tok != MDOC_Rs)
 		return;
-	if (n->next != NULL) {
+
+	if ((nn = roff_node_next(n)) != NULL) {
 		md_word(",");
-		if (n->prev != NULL &&
-		    n->prev->tok == n->tok &&
-		    n->next->tok == n->tok)
+		if (nn->tok == n->tok &&
+		    (nn = roff_node_prev(n)) != NULL &&
+		    nn->tok == n->tok)
 			md_word("and");
 	} else {
 		md_word(".");
@@ -811,10 +816,13 @@ md_pre_skip(struct roff_node *n)
 static void
 md_pre_syn(struct roff_node *n)
 {
-	if (n->prev == NULL || ! (n->flags & NODE_SYNPRETTY))
+	struct roff_node *np;
+
+	if ((n->flags & NODE_SYNPRETTY) == 0 ||
+	    (np = roff_node_prev(n)) == NULL)
 		return;
 
-	if (n->prev->tok == n->tok &&
+	if (np->tok == n->tok &&
 	    n->tok != MDOC_Ft &&
 	    n->tok != MDOC_Fo &&
 	    n->tok != MDOC_Fn) {
@@ -822,7 +830,7 @@ md_pre_syn(struct roff_node *n)
 		return;
 	}
 
-	switch (n->prev->tok) {
+	switch (np->tok) {
 	case MDOC_Fd:
 	case MDOC_Fn:
 	case MDOC_Fo:
@@ -1053,7 +1061,9 @@ md_pre_Fa(struct roff_node *n)
 static void
 md_post_Fa(struct roff_node *n)
 {
-	if (n->next != NULL && n->next->tok == MDOC_Fa)
+	struct roff_node *nn;
+
+	if ((nn = roff_node_next(n)) != NULL && nn->tok == MDOC_Fa)
 		md_word(",");
 }
 
@@ -1075,9 +1085,11 @@ md_post_Fd(struct roff_node *n)
 static void
 md_post_Fl(struct roff_node *n)
 {
+	struct roff_node *nn;
+
 	md_post_raw(n);
-	if (n->child == NULL && n->next != NULL &&
-	    n->next->type != ROFFT_TEXT && !(n->next->flags & NODE_LINE))
+	if (n->child == NULL && (nn = roff_node_next(n)) != NULL &&
+	    nn->type != ROFFT_TEXT && (nn->flags & NODE_LINE) == 0)
 		outflags &= ~MD_spc;
 }
 
diff --git a/mdoc_term.c b/mdoc_term.c
index c9f11926..776f1130 100644
--- a/mdoc_term.c
+++ b/mdoc_term.c
@@ -54,14 +54,12 @@ struct	mdoc_term_act {
 static	int	  a2width(const struct termp *, const char *);
 
 static	void	  print_bvspace(struct termp *,
-			const struct roff_node *,
-			const struct roff_node *);
+			struct roff_node *, struct roff_node *);
 static	void	  print_mdoc_node(DECL_ARGS);
 static	void	  print_mdoc_nodelist(DECL_ARGS);
 static	void	  print_mdoc_head(struct termp *, const struct roff_meta *);
 static	void	  print_mdoc_foot(struct termp *, const struct roff_meta *);
-static	void	  synopsis_pre(struct termp *,
-			const struct roff_node *);
+static	void	  synopsis_pre(struct termp *, struct roff_node *);
 
 static	void	  termp____post(DECL_ARGS);
 static	void	  termp__t_post(DECL_ARGS);
@@ -582,29 +580,20 @@ a2width(const struct termp *p, const char *v)
  * too.
  */
 static void
-print_bvspace(struct termp *p,
-	const struct roff_node *bl,
-	const struct roff_node *n)
+print_bvspace(struct termp *p, struct roff_node *bl, struct roff_node *n)
 {
-	const struct roff_node	*nn;
-
-	assert(n);
+	struct roff_node *nn;
 
 	term_newln(p);
 
-	if (MDOC_Bd == bl->tok && bl->norm->Bd.comp)
-		return;
-	if (MDOC_Bl == bl->tok && bl->norm->Bl.comp)
+	if ((bl->tok == MDOC_Bd && bl->norm->Bd.comp) ||
+	    (bl->tok == MDOC_Bl && bl->norm->Bl.comp))
 		return;
 
 	/* Do not vspace directly after Ss/Sh. */
 
 	nn = n;
-	while (nn->prev != NULL &&
-	    (nn->prev->type == ROFFT_COMMENT ||
-	     nn->prev->flags & NODE_NOPRT))
-		nn = nn->prev;
-	while (nn->prev == NULL) {
+	while (roff_node_prev(nn) == NULL) {
 		do {
 			nn = nn->parent;
 			if (nn->type == ROFFT_ROOT)
@@ -617,22 +606,18 @@ print_bvspace(struct termp *p,
 			break;
 	}
 
-	/* A `-column' does not assert vspace within the list. */
-
-	if (MDOC_Bl == bl->tok && LIST_column == bl->norm->Bl.type)
-		if (n->prev && MDOC_It == n->prev->tok)
-			return;
-
-	/* A `-diag' without body does not vspace. */
-
-	if (MDOC_Bl == bl->tok && LIST_diag == bl->norm->Bl.type)
-		if (n->prev && MDOC_It == n->prev->tok) {
-			assert(n->prev->body);
-			if (NULL == n->prev->body->child)
-				return;
-		}
+	/*
+	 * No vertical space after:
+	 * items in .Bl -column
+	 * items without a body in .Bl -diag
+	 */
 
-	term_vspace(p);
+	if (bl->tok != MDOC_Bl ||
+	    n->prev == NULL || n->prev->tok != MDOC_It ||
+	    (bl->norm->Bl.type != LIST_column &&
+	     (bl->norm->Bl.type != LIST_diag ||
+	      n->prev->body->child != NULL)))
+		term_vspace(p);
 }
 
 
@@ -1043,15 +1028,16 @@ termp_nm_post(DECL_ARGS)
 static int
 termp_fl_pre(DECL_ARGS)
 {
+	struct roff_node *nn;
 
 	termp_tag_pre(p, pair, meta, n);
 	term_fontpush(p, TERMFONT_BOLD);
 	term_word(p, "\\-");
 
-	if (!(n->child == NULL &&
-	    (n->next == NULL ||
-	     n->next->type == ROFFT_TEXT ||
-	     n->next->flags & NODE_LINE)))
+	if (n->child != NULL ||
+	    ((nn = roff_node_next(n)) != NULL &&
+	     nn->type != ROFFT_TEXT &&
+	     (nn->flags & NODE_LINE) == 0))
 		p->flags |= TERMP_NOSPACE;
 
 	return 1;
@@ -1060,10 +1046,11 @@ termp_fl_pre(DECL_ARGS)
 static int
 termp__a_pre(DECL_ARGS)
 {
+	struct roff_node *nn;
 
-	if (n->prev && MDOC__A == n->prev->tok)
-		if (NULL == n->next || MDOC__A != n->next->tok)
-			term_word(p, "and");
+	if ((nn = roff_node_prev(n)) != NULL && nn->tok == MDOC__A &&
+	    ((nn = roff_node_next(n)) == NULL || nn->tok != MDOC__A))
+		term_word(p, "and");
 
 	return 1;
 }
@@ -1104,10 +1091,9 @@ termp_ns_pre(DECL_ARGS)
 static int
 termp_rs_pre(DECL_ARGS)
 {
-
 	if (SEC_SEE_ALSO != n->sec)
 		return 1;
-	if (n->type == ROFFT_BLOCK && n->prev != NULL)
+	if (n->type == ROFFT_BLOCK && roff_node_prev(n) != NULL)
 		term_vspace(p);
 	return 1;
 }
@@ -1181,13 +1167,12 @@ termp_xr_pre(DECL_ARGS)
  * macro combos).
  */
 static void
-synopsis_pre(struct termp *p, const struct roff_node *n)
+synopsis_pre(struct termp *p, struct roff_node *n)
 {
-	/*
-	 * Obviously, if we're not in a SYNOPSIS or no prior macros
-	 * exist, do nothing.
-	 */
-	if (NULL == n->prev || ! (NODE_SYNPRETTY & n->flags))
+	struct roff_node	*np;
+
+	if ((n->flags & NODE_SYNPRETTY) == 0 ||
+	    (np = roff_node_prev(n)) == NULL)
 		return;
 
 	/*
@@ -1195,7 +1180,7 @@ synopsis_pre(struct termp *p, const struct roff_node *n)
 	 * newline and return.  UNLESS we're `Fo', `Fn', `Fn', in which
 	 * case we soldier on.
 	 */
-	if (n->prev->tok == n->tok &&
+	if (np->tok == n->tok &&
 	    MDOC_Ft != n->tok &&
 	    MDOC_Fo != n->tok &&
 	    MDOC_Fn != n->tok) {
@@ -1208,7 +1193,7 @@ synopsis_pre(struct termp *p, const struct roff_node *n)
 	 * another (or Fn/Fo, which we've let slip through) then assert
 	 * vertical space, else only newline and move on.
 	 */
-	switch (n->prev->tok) {
+	switch (np->tok) {
 	case MDOC_Fd:
 	case MDOC_Fn:
 	case MDOC_Fo:
@@ -1217,7 +1202,7 @@ synopsis_pre(struct termp *p, const struct roff_node *n)
 		term_vspace(p);
 		break;
 	case MDOC_Ft:
-		if (MDOC_Fn != n->tok && MDOC_Fo != n->tok) {
+		if (n->tok != MDOC_Fn && n->tok != MDOC_Fo) {
 			term_vspace(p);
 			break;
 		}
@@ -1271,6 +1256,7 @@ termp_fd_post(DECL_ARGS)
 static int
 termp_sh_pre(DECL_ARGS)
 {
+	struct roff_node	*np;
 
 	switch (n->type) {
 	case ROFFT_BLOCK:
@@ -1278,10 +1264,9 @@ termp_sh_pre(DECL_ARGS)
 		 * Vertical space before sections, except
 		 * when the previous section was empty.
 		 */
-		if (n->prev == NULL ||
-		    n->prev->tok != MDOC_Sh ||
-		    (n->prev->body != NULL &&
-		     n->prev->body->child != NULL))
+		if ((np = roff_node_prev(n)) == NULL ||
+		    np->tok != MDOC_Sh ||
+		    (np->body != NULL && np->body->child != NULL))
 			term_vspace(p);
 		break;
 	case ROFFT_HEAD:
@@ -1432,19 +1417,22 @@ termp_fa_pre(DECL_ARGS)
 		term_fontpush(p, TERMFONT_UNDER);
 		return 1;
 	}
-
-	for (nn = n->child; nn; nn = nn->next) {
+	for (nn = n->child; nn != NULL; nn = nn->next) {
 		term_fontpush(p, TERMFONT_UNDER);
 		p->flags |= TERMP_NBRWORD;
 		term_word(p, nn->string);
 		term_fontpop(p);
-
-		if (nn->next || (n->next && n->next->tok == MDOC_Fa)) {
+		if (nn->next != NULL) {
 			p->flags |= TERMP_NOSPACE;
 			term_word(p, ",");
 		}
 	}
-
+	if (n->child != NULL &&
+	    (nn = roff_node_next(n)) != NULL &&
+	    nn->tok == MDOC_Fa) {
+		p->flags |= TERMP_NOSPACE;
+		term_word(p, ",");
+	}
 	return 0;
 }
 
@@ -1524,24 +1512,18 @@ termp_xx_post(DECL_ARGS)
 static void
 termp_pf_post(DECL_ARGS)
 {
-
-	if ( ! (n->next == NULL || n->next->flags & NODE_LINE))
+	if (n->next != NULL && (n->next->flags & NODE_LINE) == 0)
 		p->flags |= TERMP_NOSPACE;
 }
 
 static int
 termp_ss_pre(DECL_ARGS)
 {
-	struct roff_node *nn;
-
 	switch (n->type) {
 	case ROFFT_BLOCK:
-		term_newln(p);
-		for (nn = n->prev; nn != NULL; nn = nn->prev)
-			if (nn->type != ROFFT_COMMENT &&
-			    (nn->flags & NODE_NOPRT) == 0)
-				break;
-		if (nn != NULL)
+		if (roff_node_prev(n) == NULL)
+			term_newln(p);
+		else
 			term_vspace(p);
 		break;
 	case ROFFT_HEAD:
@@ -1557,14 +1539,12 @@ termp_ss_pre(DECL_ARGS)
 	default:
 		break;
 	}
-
 	return 1;
 }
 
 static void
 termp_ss_post(DECL_ARGS)
 {
-
 	if (n->type == ROFFT_HEAD || n->type == ROFFT_BODY)
 		term_newln(p);
 }
@@ -1892,24 +1872,26 @@ termp_ap_pre(DECL_ARGS)
 static void
 termp____post(DECL_ARGS)
 {
+	struct roff_node *nn;
 
 	/*
 	 * Handle lists of authors.  In general, print each followed by
 	 * a comma.  Don't print the comma if there are only two
 	 * authors.
 	 */
-	if (MDOC__A == n->tok && n->next && MDOC__A == n->next->tok)
-		if (NULL == n->next->next || MDOC__A != n->next->next->tok)
-			if (NULL == n->prev || MDOC__A != n->prev->tok)
-				return;
+	if (n->tok == MDOC__A &&
+	    (nn = roff_node_next(n)) != NULL && nn->tok == MDOC__A &&
+	    ((nn = roff_node_next(nn)) == NULL || nn->tok != MDOC__A) &&
+	    ((nn = roff_node_prev(n)) == NULL || nn->tok != MDOC__A))
+		return;
 
 	/* TODO: %U. */
 
-	if (NULL == n->parent || MDOC_Rs != n->parent->tok)
+	if (n->parent == NULL || n->parent->tok != MDOC_Rs)
 		return;
 
 	p->flags |= TERMP_NOSPACE;
-	if (NULL == n->next) {
+	if (roff_node_next(n) == NULL) {
 		term_word(p, ".");
 		p->flags |= TERMP_SENTENCE;
 	} else
diff --git a/mdoc_validate.c b/mdoc_validate.c
index 652f9ad6..6ab715d3 100644
--- a/mdoc_validate.c
+++ b/mdoc_validate.c
@@ -1760,8 +1760,7 @@ post_bl_head(POST_ARGS)
 static void
 post_bl(POST_ARGS)
 {
-	struct roff_node	*nparent, *nprev; /* of the Bl block */
-	struct roff_node	*nblock, *nbody;  /* of the Bl */
+	struct roff_node	*nbody;           /* of the Bl */
 	struct roff_node	*nchild, *nnext;  /* of the Bl body */
 	const char		*prev_Er;
 	int			 order;
@@ -1782,88 +1781,73 @@ post_bl(POST_ARGS)
 	if (nbody->end != ENDBODY_NOT)
 		return;
 
-	nchild = nbody->child;
-	if (nchild == NULL) {
-		mandoc_msg(MANDOCERR_BLK_EMPTY,
-		    nbody->line, nbody->pos, "Bl");
-		return;
+	/*
+	 * Up to the first item, move nodes before the list,
+	 * but leave transparent nodes where they are
+	 * if they precede an item.
+	 * The next non-transparent node is kept in nchild.
+	 * It only needs to be updated after a non-transparent
+	 * node was moved out, and at the very beginning
+	 * when no node at all was moved yet.
+	 */
+
+	nchild = mdoc->last;
+	for (;;) {
+		if (nchild == mdoc->last)
+			nchild = roff_node_child(nbody);
+		if (nchild == NULL) {
+			mdoc->last = nbody;
+			mandoc_msg(MANDOCERR_BLK_EMPTY,
+			    nbody->line, nbody->pos, "Bl");
+			return;
+		}
+		if (nchild->tok == MDOC_It) {
+			mdoc->last = nbody;
+			break;
+		}
+		mandoc_msg(MANDOCERR_BL_MOVE, nbody->child->line,
+		    nbody->child->pos, "%s", roff_name[nbody->child->tok]);
+		if (nbody->parent->prev == NULL) {
+			mdoc->last = nbody->parent->parent;
+			mdoc->next = ROFF_NEXT_CHILD;
+		} else {
+			mdoc->last = nbody->parent->prev;
+			mdoc->next = ROFF_NEXT_SIBLING;
+		}
+		roff_node_relink(mdoc, nbody->child);
 	}
+
+	/*
+	 * We have reached the first item,
+	 * so moving nodes out is no longer possible.
+	 * But in .Bl -column, the first rows may be implicit,
+	 * that is, they may not start with .It macros.
+	 * Such rows may be followed by nodes generated on the
+	 * roff level, for example .TS.
+	 * Wrap such roff nodes into an implicit row.
+	 */
+
 	while (nchild != NULL) {
-		nnext = nchild->next;
-		if (nchild->tok == MDOC_It ||
-		    ((nchild->tok == MDOC_Sm || nchild->tok == MDOC_Tg) &&
-		     nnext != NULL && nnext->tok == MDOC_It)) {
-			nchild = nnext;
+		if (nchild->tok == MDOC_It) {
+			nchild = roff_node_next(nchild);
 			continue;
 		}
-
-		/*
-		 * In .Bl -column, the first rows may be implicit,
-		 * that is, they may not start with .It macros.
-		 * Such rows may be followed by nodes generated on the
-		 * roff level, for example .TS, which cannot be moved
-		 * out of the list.  In that case, wrap such roff nodes
-		 * into an implicit row.
-		 */
-
-		if (nchild->prev != NULL) {
-			mdoc->last = nchild;
-			mdoc->next = ROFF_NEXT_SIBLING;
-			roff_block_alloc(mdoc, nchild->line,
-			    nchild->pos, MDOC_It);
-			roff_head_alloc(mdoc, nchild->line,
-			    nchild->pos, MDOC_It);
+		nnext = nchild->next;
+		mdoc->last = nchild->prev;
+		mdoc->next = ROFF_NEXT_SIBLING;
+		roff_block_alloc(mdoc, nchild->line, nchild->pos, MDOC_It);
+		roff_head_alloc(mdoc, nchild->line, nchild->pos, MDOC_It);
+		mdoc->next = ROFF_NEXT_SIBLING;
+		roff_body_alloc(mdoc, nchild->line, nchild->pos, MDOC_It);
+		while (nchild->tok != MDOC_It) {
+			roff_node_relink(mdoc, nchild);
+			if (nnext == NULL)
+				break;
+			nchild = nnext;
+			nnext = nchild->next;
 			mdoc->next = ROFF_NEXT_SIBLING;
-			roff_body_alloc(mdoc, nchild->line,
-			    nchild->pos, MDOC_It);
-			while (nchild->tok != MDOC_It) {
-				roff_node_relink(mdoc, nchild);
-				if ((nchild = nnext) == NULL)
-					break;
-				nnext = nchild->next;
-				mdoc->next = ROFF_NEXT_SIBLING;
-			}
-			mdoc->last = nbody;
-			continue;
 		}
-
-		mandoc_msg(MANDOCERR_BL_MOVE, nchild->line, nchild->pos,
-		    "%s", roff_name[nchild->tok]);
-
-		/*
-		 * Move the node out of the Bl block.
-		 * First, collect all required node pointers.
-		 */
-
-		nblock  = nbody->parent;
-		nprev   = nblock->prev;
-		nparent = nblock->parent;
-
-		/*
-		 * Unlink this child.
-		 */
-
-		nbody->child = nnext;
-		if (nnext == NULL)
-			nbody->last  = NULL;
-		else
-			nnext->prev = NULL;
-
-		/*
-		 * Relink this child.
-		 */
-
-		nchild->parent = nparent;
-		nchild->prev   = nprev;
-		nchild->next   = nblock;
-
-		nblock->prev = nchild;
-		if (nprev == NULL)
-			nparent->child = nchild;
-		else
-			nprev->next = nchild;
-
-		nchild = nnext;
+		mdoc->last = nbody;
 	}
 
 	if (mdoc->meta.os_e != MANDOC_OS_NETBSD)
@@ -2500,20 +2484,20 @@ post_ignpar(POST_ARGS)
 static void
 post_prevpar(POST_ARGS)
 {
-	struct roff_node *n;
+	struct roff_node *n, *np;
 
 	n = mdoc->last;
-	if (NULL == n->prev)
-		return;
 	if (n->type != ROFFT_ELEM && n->type != ROFFT_BLOCK)
 		return;
+	if ((np = roff_node_prev(n)) == NULL)
+		return;
 
 	/*
 	 * Don't allow `Pp' prior to a paragraph-type
 	 * block: `Pp' or non-compact `Bd' or `Bl'.
 	 */
 
-	if (n->prev->tok != MDOC_Pp && n->prev->tok != ROFF_br)
+	if (np->tok != MDOC_Pp && np->tok != ROFF_br)
 		return;
 	if (n->tok == MDOC_Bl && n->norm->Bl.comp)
 		return;
@@ -2522,9 +2506,9 @@ post_prevpar(POST_ARGS)
 	if (n->tok == MDOC_It && n->parent->norm->Bl.comp)
 		return;
 
-	mandoc_msg(MANDOCERR_PAR_SKIP, n->prev->line, n->prev->pos,
-	    "%s before %s", roff_name[n->prev->tok], roff_name[n->tok]);
-	roff_node_delete(mdoc, n->prev);
+	mandoc_msg(MANDOCERR_PAR_SKIP, np->line, np->pos,
+	    "%s before %s", roff_name[np->tok], roff_name[n->tok]);
+	roff_node_delete(mdoc, np);
 }
 
 static void
diff --git a/regress/man/HP/Makefile b/regress/man/HP/Makefile
index 1e33cfb4..945f5339 100644
--- a/regress/man/HP/Makefile
+++ b/regress/man/HP/Makefile
@@ -1,6 +1,6 @@
-# $OpenBSD: Makefile,v 1.3 2019/01/06 04:41:15 schwarze Exp $
+# $OpenBSD: Makefile,v 1.4 2020/02/27 01:25:58 schwarze Exp $
 
-REGRESS_TARGETS = break literal macrotag manyargs spacing
+REGRESS_TARGETS = break literal macrotag manyargs spacing vert
 HTML_TARGETS	= literal
 
 .include <bsd.regress.mk>
diff --git a/regress/man/HP/vert.in b/regress/man/HP/vert.in
new file mode 100644
index 00000000..b433c7e0
--- /dev/null
+++ b/regress/man/HP/vert.in
@@ -0,0 +1,14 @@
+.\" $OpenBSD: vert.in,v 1.1 2020/02/27 01:25:58 schwarze Exp $
+.TH HP-VERT 1 "February 19, 2020"
+.SH NAME
+HP-vert \- vertical spacing before hanged lists
+.SH DESCRIPTION
+.PD 2v
+.HP
+Each hanged paragraph gets a sufficient amount of text
+to wrap to the next line.
+.HP
+Each hanged paragraph gets a sufficient amount of text
+to wrap to the next line.
+.LP
+Normal text.
diff --git a/regress/man/HP/vert.out_ascii b/regress/man/HP/vert.out_ascii
new file mode 100644
index 00000000..30fa3dd4
--- /dev/null
+++ b/regress/man/HP/vert.out_ascii
@@ -0,0 +1,21 @@
+HP-VERT(1)                  General Commands Manual                 HP-VERT(1)
+
+
+
+NNAAMMEE
+       HP-vert - vertical spacing before hanged lists
+
+DDEESSCCRRIIPPTTIIOONN
+       Each hanged paragraph gets a sufficient amount of text to wrap to the
+              next line.
+
+
+       Each hanged paragraph gets a sufficient amount of text to wrap to the
+              next line.
+
+
+       Normal text.
+
+
+
+OpenBSD                        February 19, 2020                    HP-VERT(1)
diff --git a/regress/man/IP/Makefile b/regress/man/IP/Makefile
index a677b970..70094e5f 100644
--- a/regress/man/IP/Makefile
+++ b/regress/man/IP/Makefile
@@ -1,7 +1,8 @@
-# $OpenBSD: Makefile,v 1.9 2019/01/06 04:41:15 schwarze Exp $
+# $OpenBSD: Makefile,v 1.10 2020/02/27 01:25:58 schwarze Exp $
 
-REGRESS_TARGETS = empty literal longhead manyargs spacing width
+REGRESS_TARGETS = bullet empty literal longhead manyargs spacing vert width
+UTF8_TARGETS	= bullet
 LINT_TARGETS	= empty
-HTML_TARGETS	= literal
+HTML_TARGETS	= bullet literal
 
 .include <bsd.regress.mk>
diff --git a/regress/man/IP/bullet.in b/regress/man/IP/bullet.in
new file mode 100644
index 00000000..138a681b
--- /dev/null
+++ b/regress/man/IP/bullet.in
@@ -0,0 +1,22 @@
+.\" $OpenBSD: bullet.in,v 1.1 2020/02/27 01:25:58 schwarze Exp $
+.TH IP-BULLET 1 "February 20, 2020"
+.SH NAME
+IP-bullet \- bullet lists
+.SH DESCRIPTION
+BEGINTEST
+.IP * 3n
+one
+.IP *
+two
+.IP \(bu
+three
+.IP \(bu
+four
+.IP \-
+five
+.IP \-
+six
+.PP
+ENDTEST
+.br
+end of file
diff --git a/regress/man/IP/bullet.out_ascii b/regress/man/IP/bullet.out_ascii
new file mode 100644
index 00000000..a01f25c2
--- /dev/null
+++ b/regress/man/IP/bullet.out_ascii
@@ -0,0 +1,28 @@
+IP-BULLET(1)                General Commands Manual               IP-BULLET(1)
+
+
+
+NNAAMMEE
+       IP-bullet - bullet lists
+
+DDEESSCCRRIIPPTTIIOONN
+       BEGINTEST
+
+       *  one
+
+       *  two
+
+       +o  three
+
+       +o  four
+
+       -  five
+
+       -  six
+
+       ENDTEST
+       end of file
+
+
+
+OpenBSD                        February 20, 2020                  IP-BULLET(1)
diff --git a/regress/man/IP/bullet.out_html b/regress/man/IP/bullet.out_html
new file mode 100644
index 00000000..95c452b0
--- /dev/null
+++ b/regress/man/IP/bullet.out_html
@@ -0,0 +1,12 @@
+<ul class="Bl-bullet">
+  <li>one</li>
+  <li>two</li>
+</ul>
+<ul class="Bl-bullet">
+  <li>three</li>
+  <li>four</li>
+</ul>
+<ul class="Bl-dash">
+  <li>five</li>
+  <li>six</li>
+</ul>
diff --git a/regress/man/IP/bullet.out_utf8 b/regress/man/IP/bullet.out_utf8
new file mode 100644
index 00000000..fa021fd5
--- /dev/null
+++ b/regress/man/IP/bullet.out_utf8
@@ -0,0 +1,28 @@
+IP-BULLET(1)                General Commands Manual               IP-BULLET(1)
+
+
+
+NNAAMMEE
+       IP-bullet - bullet lists
+
+DDEESSCCRRIIPPTTIIOONN
+       BEGINTEST
+
+       *  one
+
+       *  two
+
+       •  three
+
+       •  four
+
+       -  five
+
+       -  six
+
+       ENDTEST
+       end of file
+
+
+
+OpenBSD                        February 20, 2020                  IP-BULLET(1)
diff --git a/regress/man/IP/vert.in b/regress/man/IP/vert.in
new file mode 100644
index 00000000..cc5e2038
--- /dev/null
+++ b/regress/man/IP/vert.in
@@ -0,0 +1,10 @@
+.\" $OpenBSD: vert.in,v 1.1 2020/02/27 01:25:58 schwarze Exp $
+.TH IP-VERT 1 "February 19, 2020"
+.SH NAME
+IP-vert \- vertical spacing before indented paragraphs
+.SH DESCRIPTION
+.PD 2v
+.IP tag
+text
+.IP tag
+text
diff --git a/regress/man/IP/vert.out_ascii b/regress/man/IP/vert.out_ascii
new file mode 100644
index 00000000..428733be
--- /dev/null
+++ b/regress/man/IP/vert.out_ascii
@@ -0,0 +1,16 @@
+IP-VERT(1)                  General Commands Manual                 IP-VERT(1)
+
+
+
+NNAAMMEE
+       IP-vert - vertical spacing before indented paragraphs
+
+DDEESSCCRRIIPPTTIIOONN
+       tag    text
+
+
+       tag    text
+
+
+
+OpenBSD                        February 19, 2020                    IP-VERT(1)
diff --git a/regress/man/PP/Makefile b/regress/man/PP/Makefile
index 7655d294..a9eb9760 100644
--- a/regress/man/PP/Makefile
+++ b/regress/man/PP/Makefile
@@ -1,6 +1,6 @@
-# $OpenBSD: Makefile,v 1.4 2014/07/04 16:11:41 schwarze Exp $
+# $OpenBSD: Makefile,v 1.5 2020/02/27 01:25:58 schwarze Exp $
 
-REGRESS_TARGETS	= args empty
+REGRESS_TARGETS	= args empty vert
 LINT_TARGETS	= args empty
 
 .include <bsd.regress.mk>
diff --git a/regress/man/PP/vert.in b/regress/man/PP/vert.in
new file mode 100644
index 00000000..e15148c8
--- /dev/null
+++ b/regress/man/PP/vert.in
@@ -0,0 +1,10 @@
+.\" $OpenBSD: vert.in,v 1.1 2020/02/27 01:25:58 schwarze Exp $
+.TH PP-VERT 1 "February 19, 2020"
+.SH NAME
+PP-vert \- vertical spacing before an ordinary paragraph
+.SH DESCRIPTION
+.PD 2v
+.PP
+first paragraph
+.PP
+second paragraph
diff --git a/regress/man/PP/vert.out_ascii b/regress/man/PP/vert.out_ascii
new file mode 100644
index 00000000..ac53e071
--- /dev/null
+++ b/regress/man/PP/vert.out_ascii
@@ -0,0 +1,16 @@
+PP-VERT(1)                  General Commands Manual                 PP-VERT(1)
+
+
+
+NNAAMMEE
+       PP-vert - vertical spacing before an ordinary paragraph
+
+DDEESSCCRRIIPPTTIIOONN
+       first paragraph
+
+
+       second paragraph
+
+
+
+OpenBSD                        February 19, 2020                    PP-VERT(1)
diff --git a/regress/man/SH/Makefile b/regress/man/SH/Makefile
index 55133efe..f42a85b2 100644
--- a/regress/man/SH/Makefile
+++ b/regress/man/SH/Makefile
@@ -1,6 +1,6 @@
-# $OpenBSD: Makefile,v 1.6 2019/01/06 04:41:15 schwarze Exp $
+# $OpenBSD: Makefile,v 1.7 2020/02/27 01:25:58 schwarze Exp $
 
-REGRESS_TARGETS	= broken broken_eline empty_before longarg noarg paragraph
+REGRESS_TARGETS	= broken broken_eline empty_before longarg noarg paragraph vert
 LINT_TARGETS	= broken broken_eline empty_before noarg
 HTML_TARGETS	= paragraph
 
diff --git a/regress/man/SH/vert.in b/regress/man/SH/vert.in
new file mode 100644
index 00000000..e4154782
--- /dev/null
+++ b/regress/man/SH/vert.in
@@ -0,0 +1,10 @@
+.\" $OpenBSD: vert.in,v 1.1 2020/02/27 01:25:58 schwarze Exp $
+.TH SH-VERT 1 "February 20, 2020"
+.SH NAME
+SH-vert \- vertical spacing of sections
+.SH DESCRIPTION
+.PD 2v
+.SH EXAMPLES
+.PD 1v
+.PP
+text
diff --git a/regress/man/SH/vert.out_ascii b/regress/man/SH/vert.out_ascii
new file mode 100644
index 00000000..f8afd7e0
--- /dev/null
+++ b/regress/man/SH/vert.out_ascii
@@ -0,0 +1,14 @@
+SH-VERT(1)                  General Commands Manual                 SH-VERT(1)
+
+
+
+NNAAMMEE
+       SH-vert - vertical spacing of sections
+
+DDEESSCCRRIIPPTTIIOONN
+EEXXAAMMPPLLEESS
+       text
+
+
+
+OpenBSD                        February 20, 2020                    SH-VERT(1)
diff --git a/regress/man/SS/Makefile b/regress/man/SS/Makefile
index 0ae0fbc5..edbe4c2c 100644
--- a/regress/man/SS/Makefile
+++ b/regress/man/SS/Makefile
@@ -1,6 +1,6 @@
-# $OpenBSD: Makefile,v 1.4 2019/01/06 04:41:15 schwarze Exp $
+# $OpenBSD: Makefile,v 1.5 2020/02/27 01:25:58 schwarze Exp $
 
-REGRESS_TARGETS	= broken broken_eline longarg noarg paragraph
+REGRESS_TARGETS	= broken broken_eline longarg noarg paragraph vert
 LINT_TARGETS	= broken broken_eline noarg
 HTML_TARGETS	= paragraph
 
diff --git a/regress/man/SS/vert.in b/regress/man/SS/vert.in
new file mode 100644
index 00000000..8beb98a6
--- /dev/null
+++ b/regress/man/SS/vert.in
@@ -0,0 +1,12 @@
+.\" $OpenBSD: vert.in,v 1.1 2020/02/27 01:25:58 schwarze Exp $
+.TH SS-VERT 1 "February 19, 2020"
+.SH NAME
+SS-vert \- vertical spacing of subsections
+.SH DESCRIPTION
+.PD 2v
+.SS First subsection
+.PD 1v
+.SS Second subsection
+first paragraph
+.PP
+second paragraph
diff --git a/regress/man/SS/vert.out_ascii b/regress/man/SS/vert.out_ascii
new file mode 100644
index 00000000..9b5dc152
--- /dev/null
+++ b/regress/man/SS/vert.out_ascii
@@ -0,0 +1,17 @@
+SS-VERT(1)                  General Commands Manual                 SS-VERT(1)
+
+
+
+NNAAMMEE
+       SS-vert - vertical spacing of subsections
+
+DDEESSCCRRIIPPTTIIOONN
+   FFiirrsstt ssuubbsseeccttiioonn
+   SSeeccoonndd ssuubbsseeccttiioonn
+       first paragraph
+
+       second paragraph
+
+
+
+OpenBSD                        February 19, 2020                    SS-VERT(1)
diff --git a/regress/man/TP/Makefile b/regress/man/TP/Makefile
index 2fc1074f..ca2475b0 100644
--- a/regress/man/TP/Makefile
+++ b/regress/man/TP/Makefile
@@ -1,9 +1,9 @@
-# $OpenBSD: Makefile,v 1.15 2019/01/06 04:41:15 schwarze Exp $
+# $OpenBSD: Makefile,v 1.16 2020/02/27 01:25:58 schwarze Exp $
 
 REGRESS_TARGETS	 = badarg broken double eof fill indent literal longhead
-REGRESS_TARGETS	+= macrotag manyargs sameline spacing width
+REGRESS_TARGETS	+= macrotag manyargs sameline spacing vert width
 LINT_TARGETS	 = broken double eof
-HTML_TARGETS	 = literal
+HTML_TARGETS	 = literal vert
 
 # groff-1.22.3 defects:
 # - If .TP precedes .RE, the latter does not properly reset indentation.
diff --git a/regress/man/TP/vert.in b/regress/man/TP/vert.in
new file mode 100644
index 00000000..086976df
--- /dev/null
+++ b/regress/man/TP/vert.in
@@ -0,0 +1,17 @@
+.\" $OpenBSD: vert.in,v 1.1 2020/02/27 01:25:58 schwarze Exp $
+.TH TP-VERT 1 "February 19, 2020"
+.SH NAME
+TP-vert \- vertical spacing before tagged paragraphs
+BEGINTEST
+.SH DESCRIPTION
+.PD 2v
+.TP
+tag
+text
+.TP
+tag
+text
+.PP
+ENDTEST
+.br
+end of file
diff --git a/regress/man/TP/vert.out_ascii b/regress/man/TP/vert.out_ascii
new file mode 100644
index 00000000..32b26ca9
--- /dev/null
+++ b/regress/man/TP/vert.out_ascii
@@ -0,0 +1,20 @@
+TP-VERT(1)                  General Commands Manual                 TP-VERT(1)
+
+
+
+NNAAMMEE
+       TP-vert - vertical spacing before tagged paragraphs BEGINTEST
+
+DDEESSCCRRIIPPTTIIOONN
+       tag    text
+
+
+       tag    text
+
+
+       ENDTEST
+       end of file
+
+
+
+OpenBSD                        February 19, 2020                    TP-VERT(1)
diff --git a/regress/man/TP/vert.out_html b/regress/man/TP/vert.out_html
new file mode 100644
index 00000000..7301819f
--- /dev/null
+++ b/regress/man/TP/vert.out_html
@@ -0,0 +1,9 @@
+</section>
+<section class="Sh">
+<h1 class="Sh" id="DESCRIPTION"><a class="permalink" href="#DESCRIPTION">DESCRIPTION</a></h1>
+<dl class="Bl-tag">
+  <dt>tag</dt>
+  <dd>text</dd>
+  <dt>tag</dt>
+  <dd>text</dd>
+</dl>
diff --git a/regress/mdoc/Bd/spacing.in b/regress/mdoc/Bd/spacing.in
index 4b23da75..2346ebd7 100644
--- a/regress/mdoc/Bd/spacing.in
+++ b/regress/mdoc/Bd/spacing.in
@@ -1,4 +1,4 @@
-.\" $OpenBSD: spacing.in,v 1.3 2017/07/04 14:53:24 schwarze Exp $
+.\" $OpenBSD: spacing.in,v 1.4 2020/02/27 01:25:58 schwarze Exp $
 .Dd $Mdocdate$
 .Dt BD-SPACING 1
 .Os
@@ -15,3 +15,9 @@ text between displays
 compact display block
 .Ed
 following text
+.Sh EXAMPLES
+.Tg word
+.Bd -literal -offset indent
+text
+.Ed
+end of file
diff --git a/regress/mdoc/Bd/spacing.out_ascii b/regress/mdoc/Bd/spacing.out_ascii
index 8efa8b30..e965647c 100644
--- a/regress/mdoc/Bd/spacing.out_ascii
+++ b/regress/mdoc/Bd/spacing.out_ascii
@@ -11,4 +11,8 @@ DDEESSCCRRIIPPTTIIOONN
            compact display block
      following text
 
-OpenBSD                          July 4, 2017                          OpenBSD
+EEXXAAMMPPLLEESS
+           text
+     end of file
+
+OpenBSD                        February 27, 2020                       OpenBSD
diff --git a/regress/mdoc/Bd/spacing.out_markdown b/regress/mdoc/Bd/spacing.out_markdown
index 766dda3b..a03c20ef 100644
--- a/regress/mdoc/Bd/spacing.out_markdown
+++ b/regress/mdoc/Bd/spacing.out_markdown
@@ -16,4 +16,10 @@ text between displays
 
 following text
 
-OpenBSD - July 4, 2017
+# EXAMPLES
+
+	text
+
+end of file
+
+OpenBSD - February 27, 2020
diff --git a/regress/mdoc/Bl/Makefile b/regress/mdoc/Bl/Makefile
index 8fde5d9e..519c4055 100644
--- a/regress/mdoc/Bl/Makefile
+++ b/regress/mdoc/Bl/Makefile
@@ -1,8 +1,8 @@
-# $OpenBSD: Makefile,v 1.40 2018/12/21 16:58:49 schwarze Exp $
+# $OpenBSD: Makefile,v 1.41 2020/02/27 01:25:58 schwarze Exp $
 
 REGRESS_TARGETS  = item inset diag ohang bullet dash enum hang tag
 REGRESS_TARGETS += column column_nogroff colNoIt
-REGRESS_TARGETS += esc extend nested offset secstart
+REGRESS_TARGETS += esc extend nested offset secstart vert
 
 REGRESS_TARGETS += notype multitype badargs
 REGRESS_TARGETS += empty noIt emptyhead emptytag emptyitem multitag
diff --git a/regress/mdoc/Bl/noIt.out_lint b/regress/mdoc/Bl/noIt.out_lint
index 03a89cc5..7c6803f3 100644
--- a/regress/mdoc/Bl/noIt.out_lint
+++ b/regress/mdoc/Bl/noIt.out_lint
@@ -6,3 +6,4 @@ mandoc: noIt.in:18:2: WARNING: moving content out of list: Em
 mandoc: noIt.in:18:10: WARNING: moving content out of list: Sy
 mandoc: noIt.in:18:19: WARNING: moving content out of list: Em
 mandoc: noIt.in:24:1: WARNING: moving content out of list: text
+mandoc: noIt.in:23:2: WARNING: empty block: Bl
diff --git a/regress/mdoc/Bl/vert.in b/regress/mdoc/Bl/vert.in
new file mode 100644
index 00000000..2ff2c4ba
--- /dev/null
+++ b/regress/mdoc/Bl/vert.in
@@ -0,0 +1,15 @@
+.\" $OpenBSD: vert.in,v 1.1 2020/02/27 01:25:58 schwarze Exp $
+.Dd $Mdocdate$
+.Dt BL-VERT 1
+.Os
+.Sh NAME
+.Nm Bl-vert
+.Nd vertical spacing before lists
+.Sh DESCRIPTION
+.Bl -tag -width 7n
+.Sm off
+.It Fl o Ar file
+.Sm on
+text
+.El
+end of file
diff --git a/regress/mdoc/Bl/vert.out_ascii b/regress/mdoc/Bl/vert.out_ascii
new file mode 100644
index 00000000..24a2c565
--- /dev/null
+++ b/regress/mdoc/Bl/vert.out_ascii
@@ -0,0 +1,10 @@
+BL-VERT(1)                  General Commands Manual                 BL-VERT(1)
+
+NNAAMMEE
+     BBll--vveerrtt - vertical spacing before lists
+
+DDEESSCCRRIIPPTTIIOONN
+     --oo_f_i_l_e   text
+     end of file
+
+OpenBSD                        February 27, 2020                       OpenBSD
diff --git a/regress/mdoc/Bl/vert.out_markdown b/regress/mdoc/Bl/vert.out_markdown
new file mode 100644
index 00000000..ed741b40
--- /dev/null
+++ b/regress/mdoc/Bl/vert.out_markdown
@@ -0,0 +1,15 @@
+BL-VERT(1) - General Commands Manual
+
+# NAME
+
+**Bl-vert** - vertical spacing before lists
+
+# DESCRIPTION
+
+**-o**&zwnj;*file*
+
+> text
+
+end of file
+
+OpenBSD - February 27, 2020
diff --git a/regress/mdoc/Fl/Makefile b/regress/mdoc/Fl/Makefile
index f2b2a9aa..e4e4a6bc 100644
--- a/regress/mdoc/Fl/Makefile
+++ b/regress/mdoc/Fl/Makefile
@@ -1,6 +1,6 @@
-# $OpenBSD: Makefile,v 1.8 2014/08/21 12:56:24 schwarze Exp $
+# $OpenBSD: Makefile,v 1.13 2020/02/27 01:25:58 schwarze Exp $
 
-REGRESS_TARGETS = noarg multiarg parsed punct font
+REGRESS_TARGETS = font multiarg noarg parsed punct spacing
 LINT_TARGETS	= punct
 
 .include <bsd.regress.mk>
diff --git a/regress/mdoc/Fl/spacing.in b/regress/mdoc/Fl/spacing.in
new file mode 100644
index 00000000..8613e6b4
--- /dev/null
+++ b/regress/mdoc/Fl/spacing.in
@@ -0,0 +1,42 @@
+.\" $OpenBSD: spacing.in,v 1.1 2020/02/27 01:25:58 schwarze Exp $
+.Dd $Mdocdate$
+.Dt FL-SPACING 1
+.Os
+.Sh NAME
+.Nm Fl-spacing
+.Nd horizontal spacing after flag macros
+.Sh DESCRIPTION
+with argument:
+.Fl a
+.Pp
+no next node:
+.Xo Fl Xc suffix
+.Pp
+transparent next node only:
+.Xo Fl
+.Tg transparent1
+.Xc suffix
+.Pp
+following text:
+.Fl
+text
+.Pp
+text after transparent node on the same line:
+.Fl Es < >
+text
+.Pp
+following macro on the same line:
+.Fl Em word
+.Pp
+following macro on the next line:
+.Fl
+.Em word
+.Pp
+following macro on the next line after transparent node on the same line:
+.Fl Es < >
+.Em word
+.Pp
+following macro after transparent node on the next line:
+.Fl
+.Tg transparent3
+.Em word
diff --git a/regress/mdoc/Fl/spacing.out_ascii b/regress/mdoc/Fl/spacing.out_ascii
new file mode 100644
index 00000000..c96c3923
--- /dev/null
+++ b/regress/mdoc/Fl/spacing.out_ascii
@@ -0,0 +1,26 @@
+FL-SPACING(1)               General Commands Manual              FL-SPACING(1)
+
+NNAAMMEE
+     FFll--ssppaacciinngg - horizontal spacing after flag macros
+
+DDEESSCCRRIIPPTTIIOONN
+     with argument: --aa
+
+     no next node: -- suffix
+
+     transparent next node only: -- suffix
+
+     following text: -- text
+
+     text after transparent node on the same line: -- text
+
+     following macro on the same line: --_w_o_r_d
+
+     following macro on the next line: -- _w_o_r_d
+
+     following macro on the next line after transparent node on the same line:
+     -- _w_o_r_d
+
+     following macro after transparent node on the next line: -- _w_o_r_d
+
+OpenBSD                        February 27, 2020                       OpenBSD
diff --git a/regress/mdoc/Fl/spacing.out_markdown b/regress/mdoc/Fl/spacing.out_markdown
new file mode 100644
index 00000000..a46a44e3
--- /dev/null
+++ b/regress/mdoc/Fl/spacing.out_markdown
@@ -0,0 +1,42 @@
+FL-SPACING(1) - General Commands Manual
+
+# NAME
+
+**Fl-spacing** - horizontal spacing after flag macros
+
+# DESCRIPTION
+
+with argument:
+**-a**
+
+no next node:
+**-** suffix
+
+transparent next node only:
+**-**
+suffix
+
+following text:
+**-**
+text
+
+text after transparent node on the same line:
+**-**
+text
+
+following macro on the same line:
+**-**&zwnj;*word*
+
+following macro on the next line:
+**-**
+*word*
+
+following macro on the next line after transparent node on the same line:
+**-**
+*word*
+
+following macro after transparent node on the next line:
+**-**
+*word*
+
+OpenBSD - February 27, 2020
diff --git a/regress/mdoc/Fo/Makefile b/regress/mdoc/Fo/Makefile
index 09941a52..7770e9a1 100644
--- a/regress/mdoc/Fo/Makefile
+++ b/regress/mdoc/Fo/Makefile
@@ -1,7 +1,7 @@
-# $OpenBSD: Makefile,v 1.13 2015/02/16 11:39:34 schwarze Exp $
+# $OpenBSD: Makefile,v 1.17 2020/02/27 01:25:58 schwarze Exp $
 
 REGRESS_TARGETS	 = basic break eos font noarg nohead
-REGRESS_TARGETS += obsolete punct section warn
+REGRESS_TARGETS += obsolete punct section transp warn
 LINT_TARGETS	 = noarg nohead obsolete punct warn
 
 # groff-1.22.3 defects:
diff --git a/regress/mdoc/Fo/transp.in b/regress/mdoc/Fo/transp.in
new file mode 100644
index 00000000..78c62f6a
--- /dev/null
+++ b/regress/mdoc/Fo/transp.in
@@ -0,0 +1,23 @@
+.\" $OpenBSD: transp.in,v 1.1 2020/02/27 01:25:58 schwarze Exp $
+.Dd $Mdocdate$
+.Dt FO-TRANSP 1
+.Os
+.Sh NAME
+.Nm Fo-transp
+.Nd transparent nodes among function argument macros
+.Sh SYNOPSIS
+.Ft type
+.Fo func
+.Fa one
+.Tg one
+.Fa two
+.Tg two
+.Fc
+.Sh DESCRIPTION
+.Ft type
+.Fo func
+.Fa one
+.Tg one
+.Fa two
+.Tg two
+.Fc
diff --git a/regress/mdoc/Fo/transp.out_ascii b/regress/mdoc/Fo/transp.out_ascii
new file mode 100644
index 00000000..fb0c37fc
--- /dev/null
+++ b/regress/mdoc/Fo/transp.out_ascii
@@ -0,0 +1,13 @@
+FO-TRANSP(1)                General Commands Manual               FO-TRANSP(1)
+
+NNAAMMEE
+     FFoo--ttrraannsspp - transparent nodes among function argument macros
+
+SSYYNNOOPPSSIISS
+     _t_y_p_e
+     ffuunncc(_o_n_e, _t_w_o);
+
+DDEESSCCRRIIPPTTIIOONN
+     _t_y_p_e ffuunncc(_o_n_e, _t_w_o)
+
+OpenBSD                        February 27, 2020                       OpenBSD
diff --git a/regress/mdoc/Fo/transp.out_markdown b/regress/mdoc/Fo/transp.out_markdown
new file mode 100644
index 00000000..237d7819
--- /dev/null
+++ b/regress/mdoc/Fo/transp.out_markdown
@@ -0,0 +1,19 @@
+FO-TRANSP(1) - General Commands Manual
+
+# NAME
+
+**Fo-transp** - transparent nodes among function argument macros
+
+# SYNOPSIS
+
+*type*  
+**func**(*one*,
+*two*);
+
+# DESCRIPTION
+
+*type*
+**func**(*one*,
+*two*)
+
+OpenBSD - February 27, 2020
diff --git a/regress/mdoc/Rs/Makefile b/regress/mdoc/Rs/Makefile
index 2881b874..e6e3e1bc 100644
--- a/regress/mdoc/Rs/Makefile
+++ b/regress/mdoc/Rs/Makefile
@@ -1,6 +1,6 @@
-# $OpenBSD: Makefile,v 1.11 2019/01/07 06:51:37 schwarze Exp $
+# $OpenBSD: Makefile,v 1.12 2020/02/27 01:25:58 schwarze Exp $
 
-REGRESS_TARGETS	 = allch args break empty paragraph three_authors
+REGRESS_TARGETS	 = allch args break empty paragraph three_authors transp
 UTF8_TARGETS	 = allch break empty three_authors
 LINT_TARGETS	 = allch args empty
 HTML_TARGETS	 = paragraph
diff --git a/regress/mdoc/Rs/transp.in b/regress/mdoc/Rs/transp.in
new file mode 100644
index 00000000..6360b8a8
--- /dev/null
+++ b/regress/mdoc/Rs/transp.in
@@ -0,0 +1,36 @@
+.\" $OpenBSD: transp.in,v 1.1 2020/02/27 01:25:58 schwarze Exp $
+.Dd $Mdocdate$
+.Dt RS-TRANSPARENT 1
+.Os
+.Sh NAME
+.Nm Rs-transparent
+.Nd transparent nodes in reference blocks
+.Sh SEE ALSO
+.Tg transparent
+.Rs
+.%T title
+.%A first after title
+.%A last
+.Re
+.Rs
+.%A first
+.%A middle
+.%A last before title
+.%T title
+.Re
+.Rs
+.%T title
+.Tg transparent
+.%A first after title and transparent
+.%A middle before transparent
+.Tg transparent
+.%A last before transparent
+.Tg transparent
+.Re
+.Rs
+.Tg transparent
+.%A first after transparent
+.%A last before transparent and title
+.Tg transparent
+.%T title
+.Re
diff --git a/regress/mdoc/Rs/transp.out_ascii b/regress/mdoc/Rs/transp.out_ascii
new file mode 100644
index 00000000..cc217ed5
--- /dev/null
+++ b/regress/mdoc/Rs/transp.out_ascii
@@ -0,0 +1,16 @@
+RS-TRANSPARENT(1)           General Commands Manual          RS-TRANSPARENT(1)
+
+NNAAMMEE
+     RRss--ttrraannssppaarreenntt - transparent nodes in reference blocks
+
+SSEEEE AALLSSOO
+     first after title and last, _t_i_t_l_e.
+
+     first, middle, and last before title, _t_i_t_l_e.
+
+     first after title and transparent, middle before transparent, and last
+     before transparent, _t_i_t_l_e.
+
+     first after transparent and last before transparent and title, _t_i_t_l_e.
+
+OpenBSD                        February 27, 2020                       OpenBSD
diff --git a/regress/mdoc/Rs/transp.out_markdown b/regress/mdoc/Rs/transp.out_markdown
new file mode 100644
index 00000000..a9896335
--- /dev/null
+++ b/regress/mdoc/Rs/transp.out_markdown
@@ -0,0 +1,27 @@
+RS-TRANSPARENT(1) - General Commands Manual
+
+# NAME
+
+**Rs-transparent** - transparent nodes in reference blocks
+
+# SEE ALSO
+
+first after title,
+last,
+*title*.
+
+first,
+middle, and
+last before title,
+*title*.
+
+first after title and transparent,
+middle before transparent, and
+last before transparent,
+*title*.
+
+first after transparent,
+last before transparent and title,
+*title*.
+
+OpenBSD - February 27, 2020
diff --git a/regress/mdoc/Sh/Makefile b/regress/mdoc/Sh/Makefile
index 1c20f13f..213664ec 100644
--- a/regress/mdoc/Sh/Makefile
+++ b/regress/mdoc/Sh/Makefile
@@ -1,7 +1,8 @@
-# $OpenBSD: Makefile,v 1.11 2019/01/07 06:51:37 schwarze Exp $
+# $OpenBSD: Makefile,v 1.12 2020/02/27 01:25:58 schwarze Exp $
 
 REGRESS_TARGETS	 = badNAME before empty emptyNAME first nohead order
-REGRESS_TARGETS	+= orderNAME paragraph parbefore parborder punctNAME subbefore
+REGRESS_TARGETS	+= orderNAME paragraph parbefore parborder punctNAME
+REGRESS_TARGETS	+= subbefore transp
 LINT_TARGETS	 = badNAME before empty emptyNAME first nohead order
 LINT_TARGETS	+= orderNAME parbefore parborder punctNAME subbefore
 HTML_TARGETS	 = paragraph
diff --git a/regress/mdoc/Sh/transp.in b/regress/mdoc/Sh/transp.in
new file mode 100644
index 00000000..ef24d380
--- /dev/null
+++ b/regress/mdoc/Sh/transp.in
@@ -0,0 +1,11 @@
+.\" $OpenBSD: transp.in,v 1.1 2020/02/27 01:25:58 schwarze Exp $
+.Dd $Mdocdate$
+.Dt SH-TRANSP 1
+.Os
+.Sh NAME
+.Nm Sh-transp
+.Nd interaction of sections with transparent nodes
+.Sh DESCRIPTION
+.Tg transparent
+.Ss Subsection
+text
diff --git a/regress/mdoc/Sh/transp.out_ascii b/regress/mdoc/Sh/transp.out_ascii
new file mode 100644
index 00000000..e30d327f
--- /dev/null
+++ b/regress/mdoc/Sh/transp.out_ascii
@@ -0,0 +1,10 @@
+SH-TRANSP(1)                General Commands Manual               SH-TRANSP(1)
+
+NNAAMMEE
+     SShh--ttrraannsspp - interaction of sections with transparent nodes
+
+DDEESSCCRRIIPPTTIIOONN
+   SSuubbsseeccttiioonn
+     text
+
+OpenBSD                        February 27, 2020                       OpenBSD
diff --git a/regress/mdoc/Sh/transp.out_markdown b/regress/mdoc/Sh/transp.out_markdown
new file mode 100644
index 00000000..f395ed50
--- /dev/null
+++ b/regress/mdoc/Sh/transp.out_markdown
@@ -0,0 +1,13 @@
+SH-TRANSP(1) - General Commands Manual
+
+# NAME
+
+**Sh-transp** - interaction of sections with transparent nodes
+
+# DESCRIPTION
+
+## Subsection
+
+text
+
+OpenBSD - February 27, 2020
diff --git a/regress/mdoc/Sm/badarg.out_markdown b/regress/mdoc/Sm/badarg.out_markdown
index 903b7f81..92fc66b1 100644
--- a/regress/mdoc/Sm/badarg.out_markdown
+++ b/regress/mdoc/Sm/badarg.out_markdown
@@ -8,7 +8,6 @@ SM-BADARG(1) - General Commands Manual
 
 **-f** *on*
 **-f**&zwnj;*off* bad
-**-f** *bad* (on)
-bad**-f**&zwnj;*bad*(off)
+**-f** *bad* (on) bad**-f**&zwnj;*bad*(off)
 
 OpenBSD-July 4, 2017
diff --git a/regress/mdoc/Sm/twoarg.out_markdown b/regress/mdoc/Sm/twoarg.out_markdown
index 5b64aa6e..ce46afb1 100644
--- a/regress/mdoc/Sm/twoarg.out_markdown
+++ b/regress/mdoc/Sm/twoarg.out_markdown
@@ -8,12 +8,10 @@ SM-TWOARG(1) - General Commands Manual
 
 **default**:
 **-f** *on*  
-**off two**:
-two**-f**&zwnj;*off*  
+**off two**: two**-f**&zwnj;*off*  
 **badtwo**: bad two
 **-f** *off*  
-**on two**:
-two
+**on two**: two
 **-f** *on*
 
 OpenBSD - July 4, 2017
diff --git a/regress/mdoc/blank/Makefile b/regress/mdoc/blank/Makefile
index 7dfd0287..8b61f902 100644
--- a/regress/mdoc/blank/Makefile
+++ b/regress/mdoc/blank/Makefile
@@ -1,7 +1,7 @@
-# $OpenBSD: Makefile,v 1.5 2014/07/06 19:08:57 schwarze Exp $
+# $OpenBSD: Makefile,v 1.8 2020/02/27 01:25:59 schwarze Exp $
 
-REGRESS_TARGETS = line comment list
-LINT_TARGETS	= line comment list
+REGRESS_TARGETS = line comment list transp
+LINT_TARGETS	= line comment list transp
 
 SKIP_TMAN = list
 SKIP_MARKDOWN ?= line
diff --git a/regress/mdoc/blank/transp.in b/regress/mdoc/blank/transp.in
new file mode 100644
index 00000000..0e58bf2e
--- /dev/null
+++ b/regress/mdoc/blank/transp.in
@@ -0,0 +1,77 @@
+.\" $OpenBSD: transp.in,v 1.1 2020/02/27 01:25:59 schwarze Exp $
+.Dd $Mdocdate$
+.Dt BLANK-TRANSP 1
+.Os
+.Sh NAME
+.Nm blank-transp
+.Nd transparent nodes between line breaks
+.Sh DESCRIPTION
+Double br:
+.br
+.Tg brbr
+.br
+br Pp:
+.br
+.Tg brPp
+.Pp
+Pp br:
+.Pp
+.Tg Ppbr
+.br
+Double Pp:
+.Pp
+.Tg PpPp
+.Pp
+br sp:
+.br
+.Tg brsp
+.sp
+sp br:
+.sp
+.Tg spbr
+.br
+Pp sp:
+.Pp
+.Tg Ppsp
+.sp
+Pp sp 2v:
+.Pp
+.Tg Ppsp2v
+.sp 2v
+sp Pp:
+.sp
+.Tg spPp
+.Pp
+Double sp:
+.sp
+.Tg spsp
+.sp
+br blank:
+.br
+.Tg brbl
+
+blank br:
+
+.Tg blbr
+.br
+Pp blank:
+.Pp
+.Tg Ppbl
+
+blank Pp:
+
+.Tg blPp
+.Pp
+sp blank:
+.sp
+.Tg spbl
+
+blank sp:
+
+.Tg blsp
+.sp
+Double blank:
+
+.Tg blbl
+
+end of file
diff --git a/regress/mdoc/blank/transp.out_ascii b/regress/mdoc/blank/transp.out_ascii
new file mode 100644
index 00000000..f8bdd6b8
--- /dev/null
+++ b/regress/mdoc/blank/transp.out_ascii
@@ -0,0 +1,48 @@
+BLANK-TRANSP(1)             General Commands Manual            BLANK-TRANSP(1)
+
+NNAAMMEE
+     bbllaannkk--ttrraannsspp - transparent nodes between line breaks
+
+DDEESSCCRRIIPPTTIIOONN
+     Double br:
+     br Pp:
+
+     Pp br:
+
+     Double Pp:
+
+     br sp:
+
+     sp br:
+
+     Pp sp:
+
+     Pp sp 2v:
+
+     sp Pp:
+
+
+     Double sp:
+
+
+     br blank:
+
+     blank br:
+
+     Pp blank:
+
+     blank Pp:
+
+
+     sp blank:
+
+
+     blank sp:
+
+
+     Double blank:
+
+
+     end of file
+
+OpenBSD                        February 27, 2020                       OpenBSD
diff --git a/regress/mdoc/blank/transp.out_lint b/regress/mdoc/blank/transp.out_lint
new file mode 100644
index 00000000..533ea600
--- /dev/null
+++ b/regress/mdoc/blank/transp.out_lint
@@ -0,0 +1,19 @@
+mandoc: transp.in:52:1: WARNING: blank line in fill mode, using .sp
+mandoc: transp.in:54:1: WARNING: blank line in fill mode, using .sp
+mandoc: transp.in:60:1: WARNING: blank line in fill mode, using .sp
+mandoc: transp.in:62:1: WARNING: blank line in fill mode, using .sp
+mandoc: transp.in:68:1: WARNING: blank line in fill mode, using .sp
+mandoc: transp.in:70:1: WARNING: blank line in fill mode, using .sp
+mandoc: transp.in:74:1: WARNING: blank line in fill mode, using .sp
+mandoc: transp.in:76:1: WARNING: blank line in fill mode, using .sp
+mandoc: transp.in:12:2: WARNING: skipping paragraph macro: br after br
+mandoc: transp.in:14:2: WARNING: skipping paragraph macro: br before Pp
+mandoc: transp.in:20:2: WARNING: skipping paragraph macro: br after Pp
+mandoc: transp.in:22:2: WARNING: skipping paragraph macro: Pp before Pp
+mandoc: transp.in:26:2: WARNING: skipping paragraph macro: br before sp
+mandoc: transp.in:32:2: WARNING: skipping paragraph macro: br after sp
+mandoc: transp.in:36:2: WARNING: skipping paragraph macro: sp after Pp
+mandoc: transp.in:40:2: WARNING: skipping paragraph macro: sp after Pp
+mandoc: transp.in:50:2: WARNING: skipping paragraph macro: br before sp
+mandoc: transp.in:56:2: WARNING: skipping paragraph macro: br after sp
+mandoc: transp.in:60:1: WARNING: skipping paragraph macro: sp after Pp
diff --git a/regress/mdoc/blank/transp.out_markdown b/regress/mdoc/blank/transp.out_markdown
new file mode 100644
index 00000000..9c8ac825
--- /dev/null
+++ b/regress/mdoc/blank/transp.out_markdown
@@ -0,0 +1,44 @@
+BLANK-TRANSP(1) - General Commands Manual
+
+# NAME
+
+**blank-transp** - transparent nodes between line breaks
+
+# DESCRIPTION
+
+Double br:  
+br Pp:
+
+Pp br:
+
+Double Pp:
+
+br sp:
+
+sp br:
+
+Pp sp:
+
+Pp sp 2v:
+
+sp Pp:
+
+Double sp:
+
+br blank:
+
+blank br:
+
+Pp blank:
+
+blank Pp:
+
+sp blank:
+
+blank sp:
+
+Double blank:
+
+end of file
+
+OpenBSD - February 27, 2020
diff --git a/roff.c b/roff.c
index d5eb3f90..55172fad 100644
--- a/roff.c
+++ b/roff.c
@@ -1114,6 +1114,59 @@ roff_node_delete(struct roff_man *man, struct roff_node *n)
 	roff_node_free(n);
 }
 
+int
+roff_node_transparent(struct roff_node *n)
+{
+	if (n == NULL)
+		return 0;
+	if (n->type == ROFFT_COMMENT || n->flags & NODE_NOPRT)
+		return 1;
+	switch (n->tok) {
+	case ROFF_ft:
+	case ROFF_ll:
+	case ROFF_mc:
+	case ROFF_po:
+	case ROFF_ta:
+	case MDOC_Db:
+	case MDOC_Es:
+	case MDOC_Sm:
+	case MDOC_Tg:
+	case MAN_DT:
+	case MAN_UC:
+	case MAN_PD:
+	case MAN_AT:
+		return 1;
+	default:
+		return 0;
+	}
+}
+
+struct roff_node *
+roff_node_child(struct roff_node *n)
+{
+	for (n = n->child; roff_node_transparent(n); n = n->next)
+		continue;
+	return n;
+}
+
+struct roff_node *
+roff_node_prev(struct roff_node *n)
+{
+	do {
+		n = n->prev;
+	} while (roff_node_transparent(n));
+	return n;
+}
+
+struct roff_node *
+roff_node_next(struct roff_node *n)
+{
+	do {
+		n = n->next;
+	} while (roff_node_transparent(n));
+	return n;
+}
+
 void
 deroff(char **dest, const struct roff_node *n)
 {
diff --git a/roff.h b/roff.h
index 6cc113c9..f9aa35de 100644
--- a/roff.h
+++ b/roff.h
@@ -549,5 +549,9 @@ struct	roff_meta {
 extern	const char *const *roff_name;
 
 
-int		 arch_valid(const char *, enum mandoc_os);
-void		 deroff(char **, const struct roff_node *);
+int		  arch_valid(const char *, enum mandoc_os);
+void		  deroff(char **, const struct roff_node *);
+struct roff_node *roff_node_child(struct roff_node *);
+struct roff_node *roff_node_next(struct roff_node *);
+struct roff_node *roff_node_prev(struct roff_node *);
+int		  roff_node_transparent(struct roff_node *);
diff --git a/roff_validate.c b/roff_validate.c
index 8c0dd237..3d617214 100644
--- a/roff_validate.c
+++ b/roff_validate.c
@@ -1,6 +1,6 @@
 /*	$Id$ */
 /*
- * Copyright (c) 2010, 2017, 2018 Ingo Schwarze <schwarze@openbsd.org>
+ * Copyright (c) 2010, 2017, 2018, 2020 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
@@ -75,7 +75,7 @@ roff_valid_br(ROFF_VALID_ARGS)
 		return;
 	}
 
-	if ((np = n->prev) == NULL)
+	if ((np = roff_node_prev(n)) == NULL)
 		return;
 
 	switch (np->tok) {
@@ -129,7 +129,7 @@ roff_valid_sp(ROFF_VALID_ARGS)
 {
 	struct roff_node	*np;
 
-	if ((np = n->prev) == NULL)
+	if ((np = roff_node_prev(n)) == NULL)
 		return;
 
 	switch (np->tok) {