Support for badly nested blocks, written around the time of

the Rostock mandoc hackathon and tested and polished since,
supporting constructs like:

.Ao Bo    Ac    Bc        (exp breaking exp)
.Aq Bo    eol   Bc        (imp breaking exp)
.Ao Bq    Ac    eol       (exp breaking imp)
.Ao Bo So Bc    Ac  Sc    (double break, inner before outer)
.Ao Bo So Ac    Bc  Sc    (double break, outer before inner)
.Ao Bo    Ac So Bc  Sc    (broken breaker)
.Ao Bo So Bc Do Ac  Sc Dc (broken double breaker)

There are still two known issues which are tricky:

1) Breaking two identical explicit blocks (Ao Bo Bo Ac or Aq Bo Bo eol)
fails outright, triggering a bogus syntax error.
2) Breaking a block by two identical explicit blocks (Ao Ao Bo Ac Ac Bc
or Ao Ao Bq Ac Ac eol) still has a minor rendering error left:
"<ao1 <ao2 [bo ac2> ac1> bc]>" should not have the final ">".

We can fix these later in the tree, let's not grow this diff too large.

"get it in" kristaps@

1 files changed, 24 insertions, 7 deletions

diff --git a/mdoc_term.c b/mdoc_term.c
index cae18fa3..3ccf9de7 100644
--- a/mdoc_term.c
+++ b/mdoc_term.c
@@ -325,20 +325,37 @@ print_mdoc_node(DECL_ARGS)
 	memset(&npair, 0, sizeof(struct termpair));
 	npair.ppair = pair;
 
-	if (MDOC_TEXT != n->type) {
-		if (termacts[n->tok].pre)
-			chld = (*termacts[n->tok].pre)(p, &npair, m, n);
-	} else 
+	if (MDOC_TEXT == n->type)
 		term_word(p, n->string); 
+	else if (termacts[n->tok].pre && !n->end)
+		chld = (*termacts[n->tok].pre)(p, &npair, m, n);
 
 	if (chld && n->child)
 		print_mdoc_nodelist(p, &npair, m, n->child);
 
 	term_fontpopq(p, font);
 
-	if (MDOC_TEXT != n->type)
-		if (termacts[n->tok].post)
-			(*termacts[n->tok].post)(p, &npair, m, n);
+	if (MDOC_TEXT != n->type &&
+	    termacts[n->tok].post &&
+	    ! (MDOC_ENDED & n->flags)) {
+		(*termacts[n->tok].post)(p, &npair, m, n);
+
+		/*
+		 * Explicit end tokens not only call the post
+		 * handler, but also tell the respective block
+		 * that it must not call the post handler again.
+		 */
+		if (n->end)
+			n->pending->flags |= MDOC_ENDED;
+
+		/*
+		 * End of line terminating an implicit block
+		 * while an explicit block is still open.
+		 * Continue the explicit block without spacing.
+		 */
+		if (ENDBODY_NOSPACE == n->end)
+			p->flags |= TERMP_NOSPACE;
+	}
 
 	if (MDOC_EOS & n->flags)
 		p->flags |= TERMP_SENTENCE;