Implement the \: (optional line break) escape sequence,

documented in the Ossanna-Kernighan-Ritter troff manual
and also supported by groff.

Missing feature reported by Steffen Nurpmeso <sdaoden at gmail dot com>.

7 files changed, 48 insertions, 19 deletions

diff --git a/chars.c b/chars.c
index ad3ffd40..6370b219 100644
--- a/chars.c
+++ b/chars.c
@@ -37,7 +37,7 @@ struct	ln {
 	int		  unicode;
 };
 
-#define	LINES_MAX	  329
+#define	LINES_MAX	  330
 
 #define CHAR(in, ch, code) \
 	{ NULL, (in), (ch), (code) },
diff --git a/chars.in b/chars.in
index 28a37eaa..5b2ba028 100644
--- a/chars.in
+++ b/chars.in
@@ -1,6 +1,7 @@
 /*	$Id$ */
 /*
  * Copyright (c) 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
+ * Copyright (c) 2014 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
@@ -27,22 +28,25 @@
  * XXX - update LINES_MAX if adding more!
  */
 
-/* Non-breaking, non-collapsing space uses unit separator. */
+/* Special break control characters. */
 static const char ascii_nbrsp[2] = { ASCII_NBRSP, '\0' };
+static const char ascii_break[2] = { ASCII_BREAK, '\0' };
 
 CHAR_TBL_START
 
 /* Spacing. */
-CHAR("c",			"",		0)
-CHAR("0",			" ",		8194)
 CHAR(" ",			ascii_nbrsp,	160)
 CHAR("~",			ascii_nbrsp,	160)
-CHAR("%",			"",		0)
-CHAR("&",			"",		0)
-CHAR("^",			"",		0)
+CHAR("0",			" ",		8194)
 CHAR("|",			"",		0)
-CHAR("}",			"",		0)
+CHAR("^",			"",		0)
+CHAR("&",			"",		0)
+CHAR("%",			"",		0)
+CHAR(":",			ascii_break,	0)
+/* XXX The following three do not really belong into this file. */
 CHAR("t",			"",		0)
+CHAR("c",			"",		0)
+CHAR("}",			"",		0)
 
 /* Accents. */
 CHAR("a\"",			"\"",		779)
diff --git a/html.c b/html.c
index b61e60ac..17976fd4 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, 2012, 2013 Ingo Schwarze <schwarze@openbsd.org>
+ * Copyright (c) 2011, 2012, 2013, 2014 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
@@ -331,7 +331,8 @@ print_encode(struct html *h, const char *p, int norecurse)
 	int		 c, len, nospace;
 	const char	*seq;
 	enum mandoc_esc	 esc;
-	static const char rejs[6] = { '\\', '<', '>', '&', ASCII_HYPH, '\0' };
+	static const char rejs[8] = { '\\', '<', '>', '&',
+		ASCII_NBRSP, ASCII_HYPH, ASCII_BREAK, '\0' };
 
 	nospace = 0;
 
@@ -360,8 +361,13 @@ print_encode(struct html *h, const char *p, int norecurse)
 		case ('&'):
 			printf("&amp;");
 			continue;
+		case (ASCII_NBRSP):
+			putchar('-');
+			continue;
 		case (ASCII_HYPH):
 			putchar('-');
+			/* FALLTHROUGH */
+		case (ASCII_BREAK):
 			continue;
 		default:
 			break;
diff --git a/mandoc.h b/mandoc.h
index ab6da9a4..1827ce6d 100644
--- a/mandoc.h
+++ b/mandoc.h
@@ -20,6 +20,7 @@
 
 #define ASCII_NBRSP	 31  /* non-breaking space */
 #define	ASCII_HYPH	 30  /* breakable hyphen */
+#define	ASCII_BREAK	 29  /* breakable zero-width space */
 
 /*
  * Status level.  This refers to both internal status (i.e., whilst
diff --git a/mandocdb.c b/mandocdb.c
index 8be546b3..4a7dd1f6 100644
--- a/mandocdb.c
+++ b/mandocdb.c
@@ -1664,7 +1664,7 @@ static void
 render_key(struct mchars *mc, struct str *key)
 {
 	size_t		 sz, bsz, pos;
-	char		 utfbuf[7], res[5];
+	char		 utfbuf[7], res[6];
 	char		*buf;
 	const char	*seq, *cpp, *val;
 	int		 len, u;
@@ -1676,7 +1676,8 @@ render_key(struct mchars *mc, struct str *key)
 	res[1] = '\t';
 	res[2] = ASCII_NBRSP;
 	res[3] = ASCII_HYPH;
-	res[4] = '\0';
+	res[4] = ASCII_BREAK;
+	res[5] = '\0';
 
 	val = key->key;
 	bsz = strlen(val);
@@ -1707,15 +1708,23 @@ render_key(struct mchars *mc, struct str *key)
 			val += sz;
 		}
 
-		if (ASCII_HYPH == *val) {
+		switch (*val) {
+		case (ASCII_HYPH):
 			buf[pos++] = '-';
 			val++;
 			continue;
-		} else if ('\t' == *val || ASCII_NBRSP == *val) {
+		case ('\t'):
+			/* FALLTHROUGH */
+		case (ASCII_NBRSP):
 			buf[pos++] = ' ';
 			val++;
+			/* FALLTHROUGH */
+		case (ASCII_BREAK):
 			continue;
-		} else if ('\\' != *val)
+		default:
+			break;
+		}
+		if ('\\' != *val)
 			break;
 
 		/* Read past the slash. */
diff --git a/mdoc_man.c b/mdoc_man.c
index 9f7691d9..d1d203e8 100644
--- a/mdoc_man.c
+++ b/mdoc_man.c
@@ -1,6 +1,6 @@
 /*	$Id$ */
 /*
- * Copyright (c) 2011, 2012, 2013 Ingo Schwarze <schwarze@openbsd.org>
+ * Copyright (c) 2011, 2012, 2013, 2014 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
@@ -365,6 +365,9 @@ print_word(const char *s)
 		case (ASCII_HYPH):
 			putchar('-');
 			break;
+		case (ASCII_BREAK):
+			printf("\\:");
+			break;
 		case (' '):
 			if (MMAN_nbrword & outflags) {
 				printf("\\ ");
diff --git a/term.c b/term.c
index 9f59d113..01d6ed60 100644
--- a/term.c
+++ b/term.c
@@ -1,7 +1,7 @@
 /*	$Id$ */
 /*
  * Copyright (c) 2008, 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
- * Copyright (c) 2010, 2011, 2012, 2013 Ingo Schwarze <schwarze@openbsd.org>
+ * Copyright (c) 2010-2014 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
@@ -179,7 +179,8 @@ term_flushln(struct termp *p)
 			/* Regular word. */
 			/* Break at the hyphen point if we overrun. */
 			if (vend > vis && vend < bp && 
-					ASCII_HYPH == p->buf[j])
+			    (ASCII_HYPH == p->buf[j] ||
+			     ASCII_BREAK == p->buf[j]))
 				jhy = j;
 
 			vend += (*p->width)(p, p->buf[j]);
@@ -233,6 +234,8 @@ term_flushln(struct termp *p)
 				vbl += (*p->width)(p, ' ');
 				continue;
 			}
+			if (ASCII_BREAK == p->buf[i])
+				continue;
 
 			/*
 			 * Now we definitely know there will be
@@ -644,7 +647,8 @@ term_strlen(const struct termp *p, const char *cp)
 	int		 ssz, skip, c;
 	const char	*seq, *rhs;
 	enum mandoc_esc	 esc;
-	static const char rej[] = { '\\', ASCII_HYPH, ASCII_NBRSP, '\0' };
+	static const char rej[] = { '\\', ASCII_NBRSP, ASCII_HYPH,
+			ASCII_BREAK, '\0' };
 
 	/*
 	 * Account for escaped sequences within string length
@@ -732,6 +736,8 @@ term_strlen(const struct termp *p, const char *cp)
 		case (ASCII_HYPH):
 			sz += cond_width(p, '-', &skip);
 			cp++;
+			/* FALLTHROUGH */
+		case (ASCII_BREAK):
 			break;
 		default:
 			break;