Simplify font handling:

1. Inherit the font attribute from the parent box, such that iteration
is no longer required to find the current font.
2. For well-known function name tokens, do not insert an EQN_LISTONE
box into the AST; simply set the font attribute of the text box
itself that contains the name.

Also improve word splitting of unquoted strings in default font mode:
3. Split between numbers and punctuation because both will soon get
different HTML markup.
4. Do not split between letters.  With the newly ubiquitious font
attributes, all formatters will be able to figure out what to do
without putting each letter into a separate box.

1 files changed, 41 insertions, 37 deletions

diff --git a/eqn.c b/eqn.c
index 96c65b1b..563c35ff 100644
--- a/eqn.c
+++ b/eqn.c
@@ -1,4 +1,4 @@
-/*	$Id: eqn.c,v 1.67 2017/06/22 00:30:20 schwarze Exp $
+/*	$Id: eqn.c,v 1.68 2017/06/23 00:30:38 schwarze Exp $
 /*
  * Copyright (c) 2011, 2014 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2014, 2015, 2017 Ingo Schwarze <schwarze@openbsd.org>
@@ -573,6 +573,7 @@ eqn_box_alloc(struct eqn_node *ep, struct eqn_box *parent)
 	bp->parent = parent;
 	bp->parent->args++;
 	bp->expectargs = UINT_MAX;
+	bp->font = bp->parent->font;
 	bp->size = ep->gsize;
 
 	if (NULL != parent->first) {
@@ -721,12 +722,13 @@ static enum rofferr
 eqn_parse(struct eqn_node *ep, struct eqn_box *parent)
 {
 	char		 sym[64];
-	struct eqn_box	*cur, *fontp, *nbox;
+	struct eqn_box	*cur, *nbox;
 	const char	*cp, *cpn, *start;
 	char		*p;
 	size_t		 sz;
 	enum eqn_tok	 tok, subtok;
 	enum eqn_post	 pos;
+	enum { CCL_LET, CCL_DIG, CCL_PUN } ccl, ccln;
 	int		 size;
 
 	assert(parent != NULL);
@@ -787,6 +789,7 @@ this_tok:
 		parent = eqn_box_makebinary(ep, EQNPOS_NONE, parent);
 		parent->type = EQN_LISTONE;
 		parent->expectargs = 1;
+		parent->font = EQNFONT_ROMAN;
 		switch (tok) {
 		case EQN_TOK_DOTDOT:
 			strlcpy(sym, "\\[ad]", sizeof(sym));
@@ -1097,61 +1100,62 @@ this_tok:
 		 */
 		while (parent->args == parent->expectargs)
 			parent = parent->parent;
-		/*
-		 * Wrap well-known function names in a roman box,
-		 * unless they already are in roman context.
-		 */
-		for (fontp = parent; fontp != NULL; fontp = fontp->parent)
-			if (fontp->font != EQNFONT_NONE)
-				break;
-		if (tok == EQN_TOK_FUNC &&
-		    (fontp == NULL || fontp->font != EQNFONT_ROMAN)) {
-			parent = fontp = eqn_box_alloc(ep, parent);
-			parent->type = EQN_LISTONE;
-			parent->font = EQNFONT_ROMAN;
-			parent->expectargs = 1;
-		}
 		cur = eqn_box_alloc(ep, parent);
 		cur->type = EQN_TEXT;
 		cur->text = p;
-		/*
-		 * If not inside any explicit font context,
-		 * quoted strings become italic, and every letter
-		 * of a bare string gets its own italic box.
-		 */
-		do {
-			if (fontp != NULL || *p == '\0' ||
-			    tok == EQN_TOK_SYM)
-				break;
-			if (tok == EQN_TOK_QUOTED) {
+		switch (tok) {
+		case EQN_TOK_FUNC:
+			cur->font = EQNFONT_ROMAN;
+			break;
+		case EQN_TOK_QUOTED:
+			if (cur->font == EQNFONT_NONE)
 				cur->font = EQNFONT_ITALIC;
+			break;
+		case EQN_TOK_SYM:
+			break;
+		default:
+			if (cur->font != EQNFONT_NONE || *p == '\0')
 				break;
-			}
-			cp = p;
+			cpn = p - 1;
+			ccln = CCL_LET;
 			for (;;) {
-				if (isalpha((unsigned char)*cp))
-					cur->font = EQNFONT_ITALIC;
-				cpn = cp + 1;
+				/* Advance to next character. */
+				cp = cpn++;
+				ccl = ccln;
+				ccln = isalpha((unsigned char)*cpn) ? CCL_LET :
+				    isdigit((unsigned char)*cpn) ||
+				    (*cpn == '.' && (ccl == CCL_DIG ||
+				     isdigit((unsigned char)cpn[1]))) ?
+				    CCL_DIG : CCL_PUN;
+				/* No boundary before first character. */
+				if (cp < p)
+					continue;
+				cur->font = ccl == CCL_LET ?
+				    EQNFONT_ITALIC : EQNFONT_ROMAN;
 				if (*cp == '\\')
 					mandoc_escape(&cpn, NULL, NULL);
+				/* No boundary after last character. */
 				if (*cpn == '\0')
 					break;
-				if (cur->font != EQNFONT_ITALIC &&
-				    isalpha((unsigned char)*cpn) == 0) {
-					cp = cpn;
+				if (ccln == ccl)
 					continue;
-				}
+				/* Boundary found, add a new box. */
 				nbox = eqn_box_alloc(ep, parent);
 				nbox->type = EQN_TEXT;
 				nbox->text = mandoc_strdup(cpn);
+				/* Truncate the old box. */
 				p = mandoc_strndup(cur->text,
 				    cpn - cur->text);
 				free(cur->text);
 				cur->text = p;
+				/* Setup to process the new box. */
 				cur = nbox;
-				cp = nbox->text;
+				p = nbox->text;
+				cpn = p - 1;
+				ccln = CCL_LET;
 			}
-		} while (0);
+			break;
+		}
 		/*
 		 * Post-process list status.
 		 */