More accurately represent cells containing horizontal lines in -T tree

output.  In particular, do not represent "_" as "-", and distinguish "_"
from "\_" and "=" from "\=".
Output tweak following a related question from
Ted Bullock <tbullock at comlore dot com>.

diff --git a/usr.bin/mandoc/tree.c b/usr.bin/mandoc/tree.c
index be6dab8..98b80b5 100644 (file)
--- a/usr.bin/mandoc/tree.c
+++ b/usr.bin/mandoc/tree.c
@@ -1,7 +1,7 @@
-/* $OpenBSD: tree.c,v 1.58 2021/09/07 10:58:44 schwarze Exp $ */
+/* $OpenBSD: tree.c,v 1.59 2022/01/12 04:53:57 schwarze Exp $ */
 /*
  * Copyright (c) 2008, 2009, 2011, 2014 Kristaps Dzonsons <kristaps@bsd.lv>
- * Copyright (c) 2013-2015, 2017-2021 Ingo Schwarze <schwarze@openbsd.org>
+ * Copyright (c) 2013-2015, 2017-2022 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
@@ -507,12 +507,16 @@ print_span(const struct tbl_span *sp, int indent)
                                        putchar('x');
                        }
                        switch (dp->pos) {
-                       case TBL_DATA_HORIZ:
                        case TBL_DATA_NHORIZ:
-                               putchar('-');
+                               putchar('\\');
+                               /* FALLTHROUGH */
+                       case TBL_DATA_HORIZ:
+                               putchar('_');
                                break;
-                       case TBL_DATA_DHORIZ:
                        case TBL_DATA_NDHORIZ:
+                               putchar('\\');
+                               /* FALLTHROUGH */
+                       case TBL_DATA_DHORIZ:
                                putchar('=');
                                break;
                        default: