Split tagging into a validation part including prioritization

in tag.{h,c} and {mdoc,man}_validate.c
and into a formatting part including command line argument checking
in term_tag.{h,c}, html.c, and {mdoc|man}_{term|html}.c.

Immediate functional benefits include:
* Improved prioritization of automatic tags for .Em and .Sy.
* Avoiding bogus automatic tags when .Em, .Fn, or .Sy are explicitly tagged.
* Explicit tagging of .Er and .Fl now works in HTML output.
* Automatic tagging of .IP and .TP now works in HTML output.
But mainly, this patch provides clean earth to build further improvements on.

Technical changes:
* Main program: Write a tag file for ASCII and UTF-8 output only.
* All formatters: There is no more need to delay writing the tags.
* mdoc(7)+man(7) formatters: No more need for elaborate syntax tree inspection.
* HTML formatter: If available, use the "string" attribute as the tag.
* HTML formatter: New function to write permalinks, to reduce code duplication.

Style cleanup in the vicinity while here:
* mdoc(7) terminal formatter: To set up bold font for children,
defer to termp_bold_pre() rather than calling term_fontpush() manually.
* mdoc(7) terminal formatter: Garbage collect some duplicate functions.
* mdoc(7) HTML formatter: Unify <code> handling, delete redundant functions.
* Where possible, use switch statements rather than if cascades.
* Get rid of some more Yoda notation.

The necessity for such changes was first discussed with kn@, but i didn't
bother him with a request to review the resulting -673/+782 line patch.

1 files changed, 11 insertions, 2 deletions

diff --git a/read.c b/read.c
index b3858061..dc6c2409 100644
--- a/read.c
+++ b/read.c
@@ -1,7 +1,7 @@
-/*	$Id: read.c,v 1.214 2019/07/10 19:39:01 schwarze Exp $ */
+/* $Id: read.c,v 1.215 2020/03/13 15:32:28 schwarze Exp $ */
 /*
- * Copyright (c) 2008, 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2010-2019 Ingo Schwarze <schwarze@openbsd.org>
+ * Copyright (c) 2008, 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2010, 2012 Joerg Sonnenberger <joerg@netbsd.org>
  *
  * Permission to use, copy, modify, and distribute this software for any
@@ -15,6 +15,12 @@
  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * Top-level functions of the mandoc(3) parser:
+ * Parser and input encoding selection, decompression,
+ * handling of input bytes, characters, lines, and files,
+ * handling of roff(7) loops and file inclusion,
+ * and steering of the various parsers.
  */
 #include "config.h"
 
@@ -36,6 +42,7 @@
 #include "mandoc_aux.h"
 #include "mandoc.h"
 #include "roff.h"
+#include "tag.h"
 #include "mdoc.h"
 #include "man.h"
 #include "mandoc_parse.h"
@@ -664,6 +671,7 @@ mparse_alloc(int options, enum mandoc_os os_e, const char *os_s)
 	}
 	curp->man->meta.first->tok = TOKEN_NONE;
 	curp->man->meta.os_e = os_e;
+	tag_alloc();
 	return curp;
 }
 
@@ -680,6 +688,7 @@ mparse_reset(struct mparse *curp)
 void
 mparse_free(struct mparse *curp)
 {
+	tag_free();
 	roffhash_free(curp->man->mdocmac);
 	roffhash_free(curp->man->manmac);
 	roff_man_free(curp->man);