Implement the roff \z escape sequence, intended to output the next

character without advancing the cursor position; implement it to
simply skip the next character, as it will usually be overwritten.

With this change, the pod2man(1) preamble user-defined string \*:,
intended to render as a diaeresis or umlaut diacritic above the
preceding character, is rendered in a slightly less ugly way,
though still not correctly.  It was rendered as "z.." and is now
rendered as ".".

Given that the definition of \*: uses elaborate manual \h positioning,
there is little chance for mandoc(1) to ever render it correctly,
but at least we can refrain from printing out a spurious "z", and
we can make the \z do something semi-reasonable for easier cases.

"just commit" kristaps@

1 files changed, 57 insertions, 24 deletions

diff --git a/html.c b/html.c
index fe8a3ba8..abb868b5 100644
--- a/html.c
+++ b/html.c
@@ -1,7 +1,7 @@
 /*	$Id$ */
 /*
  * Copyright (c) 2008, 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
- * Copyright (c) 2011 Ingo Schwarze <schwarze@openbsd.org>
+ * Copyright (c) 2011, 2012 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
@@ -262,8 +262,8 @@ print_metaf(struct html *h, enum mandoc_esc deco)
 int
 html_strlen(const char *cp)
 {
-	int		 ssz, sz;
-	const char	*seq, *p;
+	size_t		 rsz;
+	int		 skip, sz;
 
 	/*
 	 * Account for escaped sequences within string length
@@ -274,10 +274,21 @@ html_strlen(const char *cp)
 	 */
 
 	sz = 0;
-	while (NULL != (p = strchr(cp, '\\'))) {
-		sz += (int)(p - cp);
-		++cp;
-		switch (mandoc_escape(&cp, &seq, &ssz)) {
+	skip = 0;
+	while (1) {
+		rsz = strcspn(cp, "\\");
+		if (rsz) {
+			cp += rsz;
+			if (skip) {
+				skip = 0;
+				rsz--;
+			}
+			sz += rsz;
+		}
+		if ('\0' == *cp)
+			break;
+		cp++;
+		switch (mandoc_escape(&cp, NULL, NULL)) {
 		case (ESCAPE_ERROR):
 			return(sz);
 		case (ESCAPE_UNICODE):
@@ -285,15 +296,19 @@ html_strlen(const char *cp)
 		case (ESCAPE_NUMBERED):
 			/* FALLTHROUGH */
 		case (ESCAPE_SPECIAL):
-			sz++;
+			if (skip)
+				skip = 0;
+			else
+				sz++;
+			break;
+		case (ESCAPE_SKIPCHAR):
+			skip = 1;
 			break;
 		default:
 			break;
 		}
 	}
-
-	assert(sz >= 0);
-	return(sz + strlen(cp));
+	return(sz);
 }
 
 static int
@@ -308,6 +323,12 @@ print_encode(struct html *h, const char *p, int norecurse)
 	nospace = 0;
 
 	while ('\0' != *p) {
+		if (HTML_SKIPCHAR & h->flags && '\\' != *p) {
+			h->flags &= ~HTML_SKIPCHAR;
+			p++;
+			continue;
+		}
+
 		sz = strcspn(p, rejs);
 
 		fwrite(p, 1, sz, stdout);
@@ -338,6 +359,31 @@ print_encode(struct html *h, const char *p, int norecurse)
 			break;
 
 		switch (esc) {
+		case (ESCAPE_FONT):
+			/* FALLTHROUGH */
+		case (ESCAPE_FONTPREV):
+			/* FALLTHROUGH */
+		case (ESCAPE_FONTBOLD):
+			/* FALLTHROUGH */
+		case (ESCAPE_FONTITALIC):
+			/* FALLTHROUGH */
+		case (ESCAPE_FONTROMAN):
+			if (0 == norecurse)
+				print_metaf(h, esc);
+			continue;
+		case (ESCAPE_SKIPCHAR):
+			h->flags |= HTML_SKIPCHAR;
+			continue;
+		default:
+			break;
+		}
+
+		if (h->flags & HTML_SKIPCHAR) {
+			h->flags &= ~HTML_SKIPCHAR;
+			continue;
+		}
+
+		switch (esc) {
 		case (ESCAPE_UNICODE):
 			/* Skip passed "u" header. */
 			c = mchars_num2uc(seq + 1, len - 1);
@@ -356,19 +402,6 @@ print_encode(struct html *h, const char *p, int norecurse)
 			else if (-1 == c && 1 == len)
 				putchar((int)*seq);
 			break;
-		case (ESCAPE_FONT):
-			/* FALLTHROUGH */
-		case (ESCAPE_FONTPREV):
-			/* FALLTHROUGH */
-		case (ESCAPE_FONTBOLD):
-			/* FALLTHROUGH */
-		case (ESCAPE_FONTITALIC):
-			/* FALLTHROUGH */
-		case (ESCAPE_FONTROMAN):
-			if (norecurse)
-				break;
-			print_metaf(h, esc);
-			break;
 		case (ESCAPE_NOSPACE):
 			if ('\0' == *p)
 				nospace = 1;