Make the code more readable by introducing

symbolic constants for tagging priorities.
This review also made me find a minor bug: do not upgrade
TAG_FALLBACK to TAG_WEAK when there is trailing whitespace.

6 files changed, 49 insertions, 32 deletions

diff --git a/main.c b/main.c
index 6cc712a2..61fee88f 100644
--- a/main.c
+++ b/main.c
@@ -1,4 +1,4 @@
-/*	$Id: main.c,v 1.340 2019/07/28 19:41:21 schwarze Exp $ */
+/*	$Id: main.c,v 1.341 2020/01/20 10:37:15 schwarze Exp $ */
 /*
  * Copyright (c) 2008-2012 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2010-2012, 2014-2019 Ingo Schwarze <schwarze@openbsd.org>
@@ -32,6 +32,7 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <glob.h>
+#include <limits.h>
 #if HAVE_SANDBOX_INIT
 #include <sandbox.h>
 #endif
diff --git a/man_term.c b/man_term.c
index d9ee14ad..553063dc 100644
--- a/man_term.c
+++ b/man_term.c
@@ -1,7 +1,7 @@
-/*	$Id: man_term.c,v 1.232 2019/07/23 17:53:35 schwarze Exp $ */
+/*	$Id: man_term.c,v 1.233 2020/01/20 10:37:15 schwarze Exp $ */
 /*
  * Copyright (c) 2008-2012 Kristaps Dzonsons <kristaps@bsd.lv>
- * Copyright (c) 2010-2015, 2017-2019 Ingo Schwarze <schwarze@openbsd.org>
+ * Copyright (c) 2010-2015, 2017-2020 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
@@ -1180,12 +1180,12 @@ tag_man(struct termp *p, struct roff_node *n)
 
 	assert(n->type == ROFFT_TEXT);
 	cp = n->string;
-	prio = 1;
+	prio = TAG_STRONG;
 	for (;;) {
 		switch (*cp) {
 		case ' ':
 		case '\t':
-			prio = INT_MAX;
+			prio = TAG_WEAK;
 			/* FALLTHROUGH */
 		case '-':
 			cp++;
diff --git a/mandoc_headers.3 b/mandoc_headers.3
index 2cda75cb..1632b07c 100644
--- a/mandoc_headers.3
+++ b/mandoc_headers.3
@@ -1,4 +1,4 @@
-.\"	$Id: mandoc_headers.3,v 1.31 2019/03/17 18:21:45 schwarze Exp $
+.\"	$Id: mandoc_headers.3,v 1.32 2020/01/20 10:37:15 schwarze Exp $
 .\"
 .\" Copyright (c) 2014-2019 Ingo Schwarze <schwarze@openbsd.org>
 .\"
@@ -14,7 +14,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: March 17 2019 $
+.Dd $Mdocdate: January 20 2020 $
 .Dt MANDOC_HEADERS 3
 .Os
 .Sh NAME
@@ -636,7 +636,11 @@ or
 Requires
 .In sys/types.h
 for
-.Vt size_t .
+.Vt size_t
+and
+.In limits.h
+for
+.Dv INT_MAX .
 .Pp
 Provides an interface to generate
 .Xr ctags 1
diff --git a/mdoc_term.c b/mdoc_term.c
index 134f82b8..e50f5423 100644
--- a/mdoc_term.c
+++ b/mdoc_term.c
@@ -1,4 +1,4 @@
-/*	$Id: mdoc_term.c,v 1.375 2020/01/19 18:02:00 schwarze Exp $ */
+/*	$Id: mdoc_term.c,v 1.376 2020/01/20 10:37:15 schwarze Exp $ */
 /*
  * Copyright (c) 2008, 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2010, 2012-2020 Ingo Schwarze <schwarze@openbsd.org>
@@ -249,7 +249,7 @@ static const struct mdoc_term_act mdoc_term_acts[MDOC_MAX - MDOC_Dd] = {
 	{ termp_tg_pre, NULL }, /* Tg */
 };
 
-static	int	 fn_prio;
+static	int	 fn_prio = TAG_STRONG;
 
 
 void
@@ -1294,7 +1294,7 @@ termp_sh_pre(DECL_ARGS)
 		term_tab_set(p, ".5i");
 		switch (n->sec) {
 		case SEC_DESCRIPTION:
-			fn_prio = 0;
+			fn_prio = TAG_STRONG;
 			break;
 		case SEC_AUTHORS:
 			p->flags &= ~(TERMP_SPLIT|TERMP_NOSPLIT);
@@ -1383,7 +1383,7 @@ termp_fn_pre(DECL_ARGS)
 	term_fontpop(p);
 
 	if (n->sec == SEC_DESCRIPTION || n->sec == SEC_CUSTOM)
-		tag_put(n->string, ++fn_prio, p->line);
+		tag_put(n->string, fn_prio++, p->line);
 
 	if (pretty) {
 		term_flushln(p);
@@ -1614,7 +1614,7 @@ termp_in_post(DECL_ARGS)
 static int
 termp_pp_pre(DECL_ARGS)
 {
-	fn_prio = 0;
+	fn_prio = TAG_STRONG;
 	term_vspace(p);
 	return 0;
 }
@@ -2039,7 +2039,7 @@ termp_em_pre(DECL_ARGS)
 {
 	if (n->child != NULL &&
 	    n->child->type == ROFFT_TEXT)
-		tag_put(n->child->string, 0, p->line);
+		tag_put(n->child->string, TAG_FALLBACK, p->line);
 	term_fontpush(p, TERMFONT_UNDER);
 	return 1;
 }
@@ -2049,7 +2049,7 @@ termp_sy_pre(DECL_ARGS)
 {
 	if (n->child != NULL &&
 	    n->child->type == ROFFT_TEXT)
-		tag_put(n->child->string, 0, p->line);
+		tag_put(n->child->string, TAG_FALLBACK, p->line);
 	term_fontpush(p, TERMFONT_BOLD);
 	return 1;
 }
@@ -2062,7 +2062,7 @@ termp_er_pre(DECL_ARGS)
 	    (n->parent->tok == MDOC_It ||
 	     (n->parent->tok == MDOC_Bq &&
 	      n->parent->parent->parent->tok == MDOC_It)))
-		tag_put(n->child->string, 1, p->line);
+		tag_put(n->child->string, TAG_STRONG, p->line);
 	return 1;
 }
 
@@ -2079,14 +2079,14 @@ termp_tag_pre(DECL_ARGS)
 	     (n->parent->tok == MDOC_Xo &&
 	      n->parent->parent->prev == NULL &&
 	      n->parent->parent->parent->tok == MDOC_It)))
-		tag_put(n->child->string, 1, p->line);
+		tag_put(n->child->string, TAG_STRONG, p->line);
 	return 1;
 }
 
 static int
 termp_tg_pre(DECL_ARGS)
 {
-	tag_put(n->child->string, -2, p->line);
+	tag_put(n->child->string, TAG_MANUAL, p->line);
 	return 0;
 }
 
diff --git a/tag.c b/tag.c
index c98c7b84..6df91c8b 100644
--- a/tag.c
+++ b/tag.c
@@ -1,4 +1,4 @@
-/*	$Id: tag.c,v 1.26 2020/01/19 18:02:00 schwarze Exp $ */
+/*	$Id: tag.c,v 1.27 2020/01/20 10:37:15 schwarze Exp $ */
 /*
  * Copyright (c) 2015,2016,2018,2019,2020 Ingo Schwarze <schwarze@openbsd.org>
  *
@@ -18,6 +18,7 @@
 
 #include <sys/types.h>
 
+#include <assert.h>
 #include <errno.h>
 #include <limits.h>
 #include <signal.h>
@@ -146,6 +147,7 @@ tag_put(const char *s, int prio, size_t line)
 	size_t			 len;
 	unsigned int		 slot;
 
+	assert(prio <= TAG_FALLBACK);
 	if (tag_files.tfd <= 0)
 		return;
 
@@ -162,8 +164,8 @@ tag_put(const char *s, int prio, size_t line)
 		return;
 
 	se = s + len;
-	if (*se != '\0')
-		prio = INT_MAX;
+	if (*se != '\0' && prio < TAG_WEAK)
+		prio = TAG_WEAK;
 
 	slot = ohash_qlookupi(&tag_data, s, &se);
 	entry = ohash_find(&tag_data, slot);
@@ -183,26 +185,25 @@ tag_put(const char *s, int prio, size_t line)
 
 		/*
 		 * Lower priority numbers take precedence,
-		 * but 0 is special.
-		 * A tag with priority 0 is only used
+		 * but TAG_FALLBACK is special.
+		 * A tag with priority TAG_FALLBACK is only used
 		 * if the tag occurs exactly once.
 		 */
 
-		if (prio == 0) {
-			if (entry->prio == 0)
-				entry->prio = -1;
+		if (prio == TAG_FALLBACK) {
+			if (entry->prio == TAG_FALLBACK)
+				entry->prio = TAG_DELETE;
 			return;
 		}
 
 		/* A better entry is already present, ignore the new one. */
 
-		if (entry->prio != -1 && entry->prio < prio)
+		if (entry->prio < prio)
 			return;
 
 		/* The existing entry is worse, clear it. */
 
-		if (entry->prio == -1 || entry->prio == 0 ||
-		    entry->prio > prio)
+		if (entry->prio > prio)
 			entry->nlines = 0;
 	}
 
@@ -242,7 +243,7 @@ tag_write(void)
 	empty = 1;
 	entry = ohash_first(&tag_data, &slot);
 	while (entry != NULL) {
-		if (stream != NULL && entry->prio != -1) {
+		if (stream != NULL && entry->prio < TAG_DELETE) {
 			for (i = 0; i < entry->nlines; i++) {
 				fprintf(stream, "%s %s %zu\n",
 				    entry->s, tag_files.ofn, entry->lines[i]);
diff --git a/tag.h b/tag.h
index 854c7db3..81ec35b4 100644
--- a/tag.h
+++ b/tag.h
@@ -1,6 +1,6 @@
-/*      $Id: tag.h,v 1.9 2019/07/27 13:40:57 schwarze Exp $    */
+/*      $Id: tag.h,v 1.10 2020/01/20 10:37:15 schwarze Exp $    */
 /*
- * Copyright (c) 2015, 2018, 2019 Ingo Schwarze <schwarze@openbsd.org>
+ * Copyright (c) 2015, 2018, 2019, 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
@@ -15,6 +15,17 @@
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
+/*
+ * Tagging priorities.
+ * Lower numbers indicate higher importance.
+ */
+#define	TAG_MANUAL	1		/* Set with a .Tg macro. */
+#define	TAG_STRONG	2		/* Good automatic tagging. */
+#define	TAG_WEAK	(INT_MAX - 2)	/* Dubious automatic tagging. */
+#define	TAG_FALLBACK	(INT_MAX - 1)	/* Tag only used if unique. */
+#define	TAG_DELETE	(INT_MAX)	/* Tag not used at all. */
+
+
 struct	tag_files {
 	char	 ofn[20];
 	char	 tfn[20];