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@.

1 files changed, 25 insertions, 13 deletions

diff --git a/usr.bin/mandoc/mdoc_markdown.c b/usr.bin/mandoc/mdoc_markdown.c
index 22b46978320..fe87440b5c1 100644
--- a/usr.bin/mandoc/mdoc_markdown.c
+++ b/usr.bin/mandoc/mdoc_markdown.c
@@ -1,6 +1,6 @@
-/*	$OpenBSD: mdoc_markdown.c,v 1.33 2020/02/20 00:29:10 schwarze Exp $ */
+/*	$OpenBSD: mdoc_markdown.c,v 1.34 2020/02/27 01:25:57 schwarze Exp $ */
 /*
- * 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;
 }