===================================================================
RCS file: /cvs/mandoc/tag.c,v
retrieving revision 1.33
retrieving revision 1.37
diff -u -p -r1.33 -r1.37
--- mandoc/tag.c	2020/04/07 22:56:02	1.33
+++ mandoc/tag.c	2022/04/26 11:38:38	1.37
@@ -1,6 +1,7 @@
-/* $Id: tag.c,v 1.33 2020/04/07 22:56:02 schwarze Exp $ */
+/* $Id: tag.c,v 1.37 2022/04/26 11:38:38 schwarze Exp $ */
 /*
- * Copyright (c) 2015,2016,2018,2019,2020 Ingo Schwarze <schwarze@openbsd.org>
+ * Copyright (c) 2015, 2016, 2018, 2019, 2020, 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
@@ -32,6 +33,7 @@
 #include "mandoc_ohash.h"
 #include "roff.h"
 #include "mdoc.h"
+#include "roff_int.h"
 #include "tag.h"
 
 struct tag_entry {
@@ -42,6 +44,8 @@ struct tag_entry {
 	char	 s[];
 };
 
+static void		 tag_move_href(struct roff_man *,
+				struct roff_node *, const char *);
 static void		 tag_move_id(struct roff_node *);
 
 static struct ohash	 tag_data;
@@ -77,18 +81,31 @@ tag_free(void)
 
 /*
  * Set a node where a term is defined,
- * unless it is already defined at a lower priority.
+ * unless the term is already defined at a lower priority.
  */
 void
 tag_put(const char *s, int prio, struct roff_node *n)
 {
 	struct tag_entry	*entry;
+	struct roff_node	*nold;
 	const char		*se;
 	size_t			 len;
 	unsigned int		 slot;
 
 	assert(prio <= TAG_FALLBACK);
 
+	/*
+	 * If the node is already tagged, the existing tag is
+	 * explicit and we are now about to add an implicit tag.
+	 * Don't do that; just skip implicit tagging if the author
+	 * specified an explicit tag.
+	 */
+
+	if (n->flags & NODE_ID)
+		return;
+
+	/* Determine the implicit tag. */
+
 	if (s == NULL) {
 		if (n->child == NULL || n->child->type != ROFFT_TEXT)
 			return;
@@ -146,7 +163,7 @@ tag_put(const char *s, int prio, struct roff_node *n)
 	 */
 
 	else if (entry->prio < prio)
-			return;
+		return;
 
 	/*
 	 * If the existing entry is worse, clear it.
@@ -155,9 +172,12 @@ tag_put(const char *s, int prio, struct roff_node *n)
 	 */
 
 	else if (entry->prio > prio || prio == TAG_FALLBACK) {
-		while (entry->nnodes > 0)
-			entry->nodes[--entry->nnodes]->flags &= ~NODE_ID;
-
+		while (entry->nnodes > 0) {
+			nold = entry->nodes[--entry->nnodes];
+			nold->flags &= ~NODE_ID;
+			free(nold->tag);
+			nold->tag = NULL;
+		}
 		if (prio == TAG_FALLBACK) {
 			entry->prio = TAG_DELETE;
 			return;
@@ -175,8 +195,8 @@ tag_put(const char *s, int prio, struct roff_node *n)
 	entry->prio = prio;
 	n->flags |= NODE_ID;
 	if (n->child == NULL || n->child->string != s || *se != '\0') {
-		assert(n->string == NULL);
-		n->string = mandoc_strndup(s, len);
+		assert(n->tag == NULL);
+		n->tag = mandoc_strndup(s, len);
 	}
 }
 
@@ -222,9 +242,9 @@ tag_move_id(struct roff_node *n)
 			}
 			/* FALLTHROUGH */
 		case MDOC_Pp:	/* Target the ROFFT_ELEM = <p>. */
-			if (np->string == NULL) {
-				np->string = mandoc_strdup(n->string == NULL ?
-				    n->child->string : n->string);
+			if (np->tag == NULL) {
+				np->tag = mandoc_strdup(n->tag == NULL ?
+				    n->child->string : n->tag);
 				np->flags |= NODE_ID;
 				n->flags &= ~NODE_ID;
 			}
@@ -249,18 +269,57 @@ tag_move_id(struct roff_node *n)
 }
 
 /*
+ * When a paragraph is tagged and starts with text,
+ * move the permalink to the first few words.
+ */
+static void
+tag_move_href(struct roff_man *man, struct roff_node *n, const char *tag)
+{
+	char	*cp;
+
+	if (n == NULL || n->type != ROFFT_TEXT ||
+	    *n->string == '\0' || *n->string == ' ')
+		return;
+
+	cp = n->string;
+	while (cp != NULL && cp - n->string < 5)
+		cp = strchr(cp + 1, ' ');
+
+	/* If the first text node is longer, split it. */
+
+	if (cp != NULL && cp[1] != '\0') {
+		man->last = n;
+		man->next = ROFF_NEXT_SIBLING;
+		roff_word_alloc(man, n->line,
+		    n->pos + (cp - n->string), cp + 1);
+		man->last->flags = n->flags & ~NODE_LINE;
+		*cp = '\0';
+	}
+
+	assert(n->tag == NULL);
+	n->tag = mandoc_strdup(tag);
+	n->flags |= NODE_HREF;
+}
+
+/*
  * When all tags have been set, decide where to put
  * the associated permalinks, and maybe move some tags
  * to the beginning of the respective paragraphs.
  */
 void
-tag_postprocess(struct roff_node *n)
+tag_postprocess(struct roff_man *man, struct roff_node *n)
 {
 	if (n->flags & NODE_ID) {
 		switch (n->tok) {
+		case MDOC_Pp:
+			tag_move_href(man, n->next, n->tag);
+			break;
 		case MDOC_Bd:
+		case MDOC_D1:
+		case MDOC_Dl:
+			tag_move_href(man, n->child, n->tag);
+			break;
 		case MDOC_Bl:
-		case MDOC_Pp:
 			/* XXX No permalink for now. */
 			break;
 		default:
@@ -268,11 +327,14 @@ tag_postprocess(struct roff_node *n)
 				tag_move_id(n);
 			if (n->tok != MDOC_Tg)
 				n->flags |= NODE_HREF;
-			else if ((n->flags & NODE_ID) == 0)
+			else if ((n->flags & NODE_ID) == 0) {
 				n->flags |= NODE_NOPRT;
+				free(n->tag);
+				n->tag = NULL;
+			}
 			break;
 		}
 	}
 	for (n = n->child; n != NULL; n = n->next)
-		tag_postprocess(n);
+		tag_postprocess(man, n);
 }