From f2e79dd041a59c1db67283d0286f14c0c5066ed4 Mon Sep 17 00:00:00 2001
From: Ingo Schwarze <schwarze@openbsd.org>
Date: Fri, 23 Jun 2017 02:32:12 +0000
Subject: Write text boxes as <mi>, <mn>, or <mo> as appropriate, and write
 fontstyle or fontweight attributes where required. Missing features reported
 by bentley@.

---
 eqn_html.c | 52 +++++++++++++++++++++++++++++++++++++++++++++++++---
 html.c     |  1 +
 html.h     |  1 +
 3 files changed, 51 insertions(+), 3 deletions(-)

diff --git a/eqn_html.c b/eqn_html.c
index 27895e48..2d23e362 100644
--- a/eqn_html.c
+++ b/eqn_html.c
@@ -20,6 +20,7 @@
 #include <sys/types.h>
 
 #include <assert.h>
+#include <ctype.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -33,7 +34,10 @@ eqn_box(struct html *p, const struct eqn_box *bp)
 {
 	struct tag	*post, *row, *cell, *t;
 	const struct eqn_box *child, *parent;
+	const unsigned char *cp;
 	size_t		 i, j, rows;
+	enum htmltag	 tag;
+	enum eqn_fontt	 font;
 
 	if (NULL == bp)
 		return;
@@ -136,9 +140,51 @@ eqn_box(struct html *p, const struct eqn_box *bp)
 		print_otag(p, TAG_MTD, "");
 	}
 
-	if (NULL != bp->text) {
-		assert(NULL == post);
-		post = print_otag(p, TAG_MI, "");
+	if (bp->text != NULL) {
+		assert(post == NULL);
+		tag = TAG_MI;
+		cp = (unsigned char *)bp->text;
+		if (isdigit(cp[0]) || (cp[0] == '.' && isdigit(cp[1]))) {
+			tag = TAG_MN;
+			while (*++cp != '\0') {
+				if (*cp != '.' && !isdigit(*cp)) {
+					tag = TAG_MI;
+					break;
+				}
+			}
+		} else if (*cp != '\0' && isalpha(*cp) == 0) {
+			tag = TAG_MO;
+			while (*++cp != '\0') {
+				if (isalnum(*cp)) {
+					tag = TAG_MI;
+					break;
+				}
+			}
+		}
+		font = bp->font;
+		if (bp->text[0] != '\0' &&
+		    (((tag == TAG_MN || tag == TAG_MO) &&
+		      font == EQNFONT_ROMAN) ||
+		     (tag == TAG_MI && font == (bp->text[1] == '\0' ?
+		      EQNFONT_ITALIC : EQNFONT_ROMAN))))
+			font = EQNFONT_NONE;
+		switch (font) {
+		case EQNFONT_NONE:
+			post = print_otag(p, tag, "");
+			break;
+		case EQNFONT_ROMAN:
+			post = print_otag(p, tag, "?", "fontstyle", "normal");
+			break;
+		case EQNFONT_BOLD:
+		case EQNFONT_FAT:
+			post = print_otag(p, tag, "?", "fontweight", "bold");
+			break;
+		case EQNFONT_ITALIC:
+			post = print_otag(p, tag, "?", "fontstyle", "italic");
+			break;
+		default:
+			abort();
+		}
 		print_text(p, bp->text);
 	} else if (NULL == post) {
 		if (NULL != bp->left || NULL != bp->right)
diff --git a/html.c b/html.c
index c7037ad0..53e76149 100644
--- a/html.c
+++ b/html.c
@@ -87,6 +87,7 @@ static	const struct htmldata htmltags[TAG_MAX] = {
 	{"math",	HTML_NLALL | HTML_INDENT},
 	{"mrow",	0},
 	{"mi",		0},
+	{"mn",		0},
 	{"mo",		0},
 	{"msup",	0},
 	{"msub",	0},
diff --git a/html.h b/html.h
index f7785e2f..eef388fa 100644
--- a/html.h
+++ b/html.h
@@ -51,6 +51,7 @@ enum	htmltag {
 	TAG_MATH,
 	TAG_MROW,
 	TAG_MI,
+	TAG_MN,
 	TAG_MO,
 	TAG_MSUP,
 	TAG_MSUB,
-- 
cgit