Finished: unifying the escape-sequence parser.

[Kristaps Dzonsons <kristaps@bsd.lv>]

[-- Attachment #1: Type: text/plain, Size: 1290 bytes --]

>> Step 3: fixed where I forgot to for->while in mdoc_validate.c's
>> check_text() loop; removed DECO_SSPECIAL; cleaned up DECO_NOSPACE;
>> cleaned up print_encode() in html.c. The next will be removing the DECO
>> stuff entirely.
>
> Ok (step 4?), one last patch to show full fidelity between DECO and
> ESCAPE before I rip out DECO stuff. This also comes with a fix of a
> yet-unnoticed bug: \F escapes were being treated as \f escapes in terms
> of recognising styles (bold, italic, etc.). However, in the groff
> manual, \F accepts families (Times, Helvetica, etc.) while \f accepts
> styles (duh). I've actually completely removed the FONTFAMILY notion, as
> we don't really support it (it can be put in later, if necessary, but
> it's unlikely as it can't be reliably displayed across output media).

Hi,

Here's the finished patch: enum roffdeco has been completely removed and 
all components are dipping into mandoc_escape() to get the correct 
subsequences.

This has resulted in some clean-up throughout the code, as all the mess 
of escapes is focussed in one place.  It's also given me a chance to 
clean up other areas in the code that danced around string handling 
(e.g., print_encode() in html.c, term_strlen() and term_word() in 
term.c, etc.).

Oks?  Comments?

Kristaps

[-- Attachment #2: patch.escapes.txt --]
[-- Type: text/plain, Size: 30273 bytes --]

? chat.8
? config.h
? config.log
? eqn.7.html
? eqn.7.pdf
? eqn.7.ps
? eqn.7.txt
? eqn.7.xhtml
? foo.1
? foo.1.html
? foo.3
? foo.ps
? index.html
? ksh.1
? man.7.html
? man.7.pdf
? man.7.ps
? man.7.txt
? man.7.xhtml
? man.h.html
? man.txt
? mandoc
? mandoc-db.bak.c
? mandoc.1.html
? mandoc.1.pdf
? mandoc.1.ps
? mandoc.1.txt
? mandoc.1.xhtml
? mandoc.3.html
? mandoc.3.pdf
? mandoc.3.ps
? mandoc.3.txt
? mandoc.3.xhtml
? mandoc.db
? mandoc.h.html
? mandoc.index
? mandoc_char.7.html
? mandoc_char.7.pdf
? mandoc_char.7.ps
? mandoc_char.7.txt
? mandoc_char.7.xhtml
? manuals.txt
? mdoc.7.html
? mdoc.7.pdf
? mdoc.7.ps
? mdoc.7.txt
? mdoc.7.xhtml
? mdoc.h.html
? mdocml.md5
? mdocml.tar.gz
? patch.escapes.txt
? patch.mdoc.txt
? patch.roff.txt
? patch.txt
? roff.7.html
? roff.7.pdf
? roff.7.ps
? roff.7.txt
? roff.7.xhtml
? tbl.7.html
? tbl.7.pdf
? tbl.7.ps
? tbl.7.txt
? tbl.7.xhtml
Index: html.c
===================================================================
RCS file: /usr/vhosts/mdocml.bsd.lv/cvs/mdocml/html.c,v
retrieving revision 1.131
diff -u -r1.131 html.c
--- html.c	22 Mar 2011 14:05:45 -0000	1.131
+++ html.c	8 Apr 2011 13:54:20 -0000
@@ -94,14 +94,13 @@
 };
 
 static	void		  print_num(struct html *, const char *, size_t);
-static	void		  print_spec(struct html *, enum roffdeco,
-				const char *, size_t);
+static	void		  print_spec(struct html *, const char *, size_t);
 static	void		  print_res(struct html *, const char *, size_t);
 static	void		  print_ctag(struct html *, enum htmltag);
 static	void		  print_doctype(struct html *);
 static	void		  print_xmltype(struct html *);
 static	int		  print_encode(struct html *, const char *, int);
-static	void		  print_metaf(struct html *, enum roffdeco);
+static	void		  print_metaf(struct html *, enum mandoc_esc);
 static	void		  print_attr(struct html *, 
 				const char *, const char *);
 static	void		 *ml_alloc(char *, enum htmltype);
@@ -221,7 +220,7 @@
 }
 
 static void
-print_spec(struct html *h, enum roffdeco d, const char *p, size_t len)
+print_spec(struct html *h, const char *p, size_t len)
 {
 	int		 cp;
 	const char	*rhs;
@@ -230,7 +229,7 @@
 	if ((cp = chars_spec2cp(h->symtab, p, len)) > 0) {
 		printf("&#%d;", cp);
 		return;
-	} else if (-1 == cp && DECO_SSPECIAL == d) {
+	} else if (-1 == cp && 1 == len) {
 		fwrite(p, 1, len, stdout);
 		return;
 	} else if (-1 == cp)
@@ -260,21 +259,21 @@
 
 
 static void
-print_metaf(struct html *h, enum roffdeco deco)
+print_metaf(struct html *h, enum mandoc_esc deco)
 {
 	enum htmlfont	 font;
 
 	switch (deco) {
-	case (DECO_PREVIOUS):
+	case (ESCAPE_FONTPREV):
 		font = h->metal;
 		break;
-	case (DECO_ITALIC):
+	case (ESCAPE_FONTITALIC):
 		font = HTMLFONT_ITALIC;
 		break;
-	case (DECO_BOLD):
+	case (ESCAPE_FONTBOLD):
 		font = HTMLFONT_BOLD;
 		break;
-	case (DECO_ROMAN):
+	case (ESCAPE_FONTROMAN):
 		font = HTMLFONT_NONE;
 		break;
 	default:
@@ -303,73 +302,69 @@
 	size_t		 sz;
 	int		 len, nospace;
 	const char	*seq;
-	enum roffdeco	 deco;
+	enum mandoc_esc	 esc;
 	static const char rejs[6] = { '\\', '<', '>', '&', ASCII_HYPH, '\0' };
 
 	nospace = 0;
 
-	for (; *p; p++) {
+	while ('\0' != *p) {
 		sz = strcspn(p, rejs);
 
 		fwrite(p, 1, sz, stdout);
-		p += /* LINTED */
-			sz;
+		p += (int)sz;
 
-		if ('<' == *p) {
+		if ('\0' == *p)
+			break;
+
+		switch (*p++) {
+		case ('<'):
 			printf("&lt;");
 			continue;
-		} else if ('>' == *p) {
+		case ('>'):
 			printf("&gt;");
 			continue;
-		} else if ('&' == *p) {
+		case ('&'):
 			printf("&amp;");
 			continue;
-		} else if (ASCII_HYPH == *p) {
-			/*
-			 * Note: "soft hyphens" aren't graphically
-			 * displayed when not breaking the text; we want
-			 * them to be displayed.
-			 */
-			/*printf("&#173;");*/
+		case (ASCII_HYPH):
 			putchar('-');
 			continue;
-		} else if ('\0' == *p)
+		default:
 			break;
+		}
 
-		seq = ++p;
-		len = a2roffdeco(&deco, &seq, &sz);
+		esc = mandoc_escape(&p, &seq, &len);
+		if (ESCAPE_ERROR == esc)
+			break;
 
-		switch (deco) {
-		case (DECO_NUMBERED):
-			print_num(h, seq, sz);
+		switch (esc) {
+		case (ESCAPE_NUMBERED):
+			print_num(h, seq, len);
 			break;
-		case (DECO_RESERVED):
-			print_res(h, seq, sz);
+		case (ESCAPE_PREDEF):
+			print_res(h, seq, len);
 			break;
-		case (DECO_SSPECIAL):
-			/* FALLTHROUGH */
-		case (DECO_SPECIAL):
-			print_spec(h, deco, seq, sz);
+		case (ESCAPE_SPECIAL):
+			print_spec(h, seq, len);
 			break;
-		case (DECO_PREVIOUS):
+		case (ESCAPE_FONTPREV):
 			/* FALLTHROUGH */
-		case (DECO_BOLD):
+		case (ESCAPE_FONTBOLD):
 			/* FALLTHROUGH */
-		case (DECO_ITALIC):
+		case (ESCAPE_FONTITALIC):
 			/* FALLTHROUGH */
-		case (DECO_ROMAN):
+		case (ESCAPE_FONTROMAN):
 			if (norecurse)
 				break;
-			print_metaf(h, deco);
+			print_metaf(h, esc);
+			break;
+		case (ESCAPE_NOSPACE):
+			if ('\0' == *p)
+				nospace = 1;
 			break;
 		default:
 			break;
 		}
-
-		p += len - 1;
-
-		if (DECO_NOSPACE == deco && '\0' == *(p + 1))
-			nospace = 1;
 	}
 
 	return(nospace);
Index: libmandoc.h
===================================================================
RCS file: /usr/vhosts/mdocml.bsd.lv/cvs/mdocml/libmandoc.h,v
retrieving revision 1.17
diff -u -r1.17 libmandoc.h
--- libmandoc.h	28 Mar 2011 23:52:13 -0000	1.17
+++ libmandoc.h	8 Apr 2011 13:54:20 -0000
@@ -73,7 +73,6 @@
 			int, int, const char *);
 void		 mandoc_vmsg(enum mandocerr, struct mparse *, 
 			int, int, const char *, ...);
-int		 mandoc_special(char *);
 char		*mandoc_strdup(const char *);
 char		*mandoc_getarg(struct mparse *, char **, int, int *);
 char		*mandoc_normdate(struct mparse *, char *, int, int);
Index: man_validate.c
===================================================================
RCS file: /usr/vhosts/mdocml.bsd.lv/cvs/mdocml/man_validate.c,v
retrieving revision 1.67
diff -u -r1.67 man_validate.c
--- man_validate.c	22 Mar 2011 15:30:30 -0000	1.67
+++ man_validate.c	8 Apr 2011 13:54:20 -0000
@@ -54,7 +54,7 @@
 static	int	  check_part(CHKARGS);
 static	int	  check_root(CHKARGS);
 static	int	  check_sec(CHKARGS);
-static	int	  check_text(CHKARGS);
+static	void	  check_text(CHKARGS);
 
 static	int	  post_AT(CHKARGS);
 static	int	  post_fi(CHKARGS);
@@ -151,7 +151,8 @@
 
 	switch (m->last->type) {
 	case (MAN_TEXT): 
-		return(check_text(m, m->last));
+		check_text(m, m->last);
+		return(1);
 	case (MAN_ROOT):
 		return(check_root(m, m->last));
 	case (MAN_EQN):
@@ -204,43 +205,48 @@
 	return(1);
 }
 
-
-static int
+static void
 check_text(CHKARGS) 
 {
-	char		*p;
-	int		 pos, c;
+	char		*p, *pp, *cpp;
+	int		 pos;
 	size_t		 sz;
 
-	for (p = n->string, pos = n->pos + 1; *p; p++, pos++) {
-		sz = strcspn(p, "\t\\");
-		p += (int)sz;
+	p = n->string;
+	pos = n->pos + 1;
 
-		if ('\0' == *p)
-			break;
+	while ('\0' != *p) {
+		sz = strcspn(p, "\t\\");
 
+		p += (int)sz;
 		pos += (int)sz;
 
 		if ('\t' == *p) {
-			if (MAN_LITERAL & m->flags)
-				continue;
-			man_pmsg(m, n->line, pos, MANDOCERR_BADTAB);
+			if ( ! (MAN_LITERAL & m->flags))
+				man_pmsg(m, n->line, pos, MANDOCERR_BADTAB);
+			p++;
+			pos++;
 			continue;
-		}
+		} else if ('\0' == *p)
+			break;
 
-		/* Check the special character. */
+		pos++;
+		pp = ++p;
 
-		c = mandoc_special(p);
-		if (c) {
-			p += c - 1;
-			pos += c - 1;
-		} else
+		if (ESCAPE_ERROR == mandoc_escape
+				((const char **)&pp, NULL, NULL)) {
 			man_pmsg(m, n->line, pos, MANDOCERR_BADESCAPE);
-	}
+			break;
+		}
 
-	return(1);
-}
+		cpp = p;
+		while (NULL != (cpp = memchr(cpp, ASCII_HYPH, pp - cpp)))
+			*cpp = '-';
 
+		pos += pp - p;
+		p = pp;
+	}
+}
 
 #define	INEQ_DEFINE(x, ineq, name) \
 static int \
Index: mandoc.c
===================================================================
RCS file: /usr/vhosts/mdocml.bsd.lv/cvs/mdocml/mandoc.c,v
retrieving revision 1.44
diff -u -r1.44 mandoc.c
--- mandoc.c	28 Mar 2011 23:52:13 -0000	1.44
+++ mandoc.c	8 Apr 2011 13:54:20 -0000
@@ -35,198 +35,362 @@
 
 static	int	 a2time(time_t *, const char *, const char *);
 static	char	*time2a(time_t);
+static	int	 numescape(const char *);
 
-int
-mandoc_special(char *p)
+/*
+ * Pass over recursive numerical expressions.  This context of this
+ * function is important: it's only called within character-terminating
+ * escapes (e.g., \s[xxxyyy]), so all we need to do is handle initial
+ * recursion: we don't care about what's in these blocks. 
+ * This returns the number of characters skipped or -1 if an error
+ * occurs (the caller should bail).
+ */
+static int
+numescape(const char *start)
 {
-	int		 len, i;
-	char		 term;
-	char		*sv;
-	
-	len = 0;
+	int		 i;
+	size_t		 sz;
+	const char	*cp;
+
+	i = 0;
+
+	/* The expression consists of a subexpression. */
+
+	if ('\\' == start[i]) {
+		cp = &start[++i];
+		/*
+		 * Read past the end of the subexpression.
+		 * Bail immediately on errors.
+		 */
+		if (ESCAPE_ERROR == mandoc_escape(&cp, NULL, NULL))
+			return(-1);
+		return(i + cp - &start[i]);
+	} 
+
+	if ('(' != start[i++])
+		return(0);
+
+	/*
+	 * A parenthesised subexpression.  Read until the closing
+	 * parenthesis, making sure to handle any nested subexpressions
+	 * that might ruin our parse.
+	 */
+
+	while (')' != start[i]) {
+		sz = strcspn(&start[i], ")\\");
+		i += (int)sz;
+
+		if ('\0' == start[i])
+			return(-1);
+		else if ('\\' != start[i])
+			continue;
+
+		cp = &start[++i];
+		if (ESCAPE_ERROR == mandoc_escape(&cp, NULL, NULL))
+			return(-1);
+		i += cp - &start[i];
+	}
+
+	/* Read past the terminating ')'. */
+	return(++i);
+}
+
+/*
+ * Handle an escaped sequeence.  This should be called with any
+ * string subsequent a `\'.  Pass a pointer to this substring as "end";
+ * it will be set to the supremum of the parsed escape sequence.  If
+ * this returns ESCAPE_ERROR, the string is bogus and should be thrown
+ * away.  If not ESCAPE_ERROR or ESCAPE_IGNORE, "start" is set to the
+ * first relevant character of the substring (font, glyph, whatever) of
+ * length sz.  Both "start" and "sz" may be NULL.
+ */
+enum mandoc_esc
+mandoc_escape(const char **end, const char **start, int *sz)
+{
+	char		 c, term, numeric;
+	int		 i, lim, ssz, rlim;
+	const char	*cp, *rstart;
+	enum mandoc_esc	 gly; 
+
+	cp = *end;
+	rstart = cp;
+	if (start)
+		*start = rstart;
+	i = 0;
+	gly = ESCAPE_ERROR;
 	term = '\0';
-	sv = p;
+	numeric = 0;
 
-	assert('\\' == *p);
-	p++;
+	switch ((c = cp[i++])) {
+	/*
+	 * First the glyphs.  There are several different forms of
+	 * these, but each eventually returns a substring of the glyph
+	 * name.
+	 */
+	case ('('):
+		gly = ESCAPE_SPECIAL;
+		lim = 2;
+		break;
+	case ('['):
+		gly = ESCAPE_SPECIAL;
+		term = ']';
+		break;
+	case ('C'):
+		if ('\'' != cp[i])
+			return(ESCAPE_ERROR);
+		gly = ESCAPE_SPECIAL;
+		term = '\'';
+		break;
 
-	switch (*p++) {
-#if 0
-	case ('Z'):
-		/* FALLTHROUGH */
-	case ('X'):
-		/* FALLTHROUGH */
-	case ('x'):
-		/* FALLTHROUGH */
-	case ('S'):
-		/* FALLTHROUGH */
-	case ('R'):
-		/* FALLTHROUGH */
-	case ('N'):
-		/* FALLTHROUGH */
-	case ('l'):
-		/* FALLTHROUGH */
-	case ('L'):
-		/* FALLTHROUGH */
-	case ('H'):
+	/*
+	 * Handle all triggers matching \X(xy, \Xx, and \X[xxxx], where
+	 * 'X' is the trigger.  These have opaque sub-strings.
+	 */
+	case ('F'):
 		/* FALLTHROUGH */
-	case ('h'):
+	case ('g'):
 		/* FALLTHROUGH */
-	case ('D'):
+	case ('k'):
 		/* FALLTHROUGH */
-	case ('C'):
+	case ('M'):
 		/* FALLTHROUGH */
-	case ('b'):
+	case ('m'):
 		/* FALLTHROUGH */
-	case ('B'):
+	case ('n'):
 		/* FALLTHROUGH */
-	case ('a'):
+	case ('V'):
 		/* FALLTHROUGH */
-	case ('A'):
-		if (*p++ != '\'')
-			return(0);
-		term = '\'';
-		break;
-#endif
-	case ('h'):
+	case ('Y'):
+		if (ESCAPE_ERROR == gly)
+			gly = ESCAPE_IGNORE;
 		/* FALLTHROUGH */
-	case ('v'):
+	case ('*'):
+		if (ESCAPE_ERROR == gly)
+			gly = ESCAPE_PREDEF;
 		/* FALLTHROUGH */
-	case ('s'):
-		if (ASCII_HYPH == *p)
-			*p = '-';
+	case ('f'):
+		if (ESCAPE_ERROR == gly)
+			gly = ESCAPE_FONT;
 
-		i = 0;
-		if ('+' == *p || '-' == *p) {
-			p++;
-			i = 1;
-		}
+		rstart= &cp[i];
+		if (start) 
+			*start = rstart;
 
-		switch (*p++) {
+		switch (cp[i++]) {
 		case ('('):
-			len = 2;
+			lim = 2;
 			break;
 		case ('['):
 			term = ']';
 			break;
-		case ('\''):
-			term = '\'';
-			break;
-		case ('0'):
-			i = 1;
-			/* FALLTHROUGH */
 		default:
-			len = 1;
-			p--;
+			lim = 1;
+			i--;
 			break;
 		}
+		break;
 
-		if (ASCII_HYPH == *p)
-			*p = '-';
-		if ('+' == *p || '-' == *p) {
-			if (i)
-				return(0);
-			p++;
-		} 
-		
-		/* Handle embedded numerical subexp or escape. */
-
-		if ('(' == *p) {
-			while (*p && ')' != *p)
-				if ('\\' == *p++) {
-					i = mandoc_special(--p);
-					if (0 == i)
-						return(0);
-					p += i;
-				}
-
-			if (')' == *p++)
-				break;
-
-			return(0);
-		} else if ('\\' == *p) {
-			if (0 == (i = mandoc_special(p)))
-				return(0);
-			p += i;
-		}
-
+	/*
+	 * These escapes are of the form \X'Y', where 'X' is the trigger
+	 * and 'Y' is any string.  These have opaque sub-strings.
+	 */
+	case ('A'):
+		/* FALLTHROUGH */
+	case ('b'):
+		/* FALLTHROUGH */
+	case ('D'):
+		/* FALLTHROUGH */
+	case ('o'):
+		/* FALLTHROUGH */
+	case ('R'):
+		/* FALLTHROUGH */
+	case ('X'):
+		/* FALLTHROUGH */
+	case ('Z'):
+		if ('\'' != cp[i++])
+			return(ESCAPE_ERROR);
+		gly = ESCAPE_IGNORE;
+		term = '\'';
 		break;
-#if 0
-	case ('Y'):
+
+	/*
+	 * These escapes are of the form \X'N', where 'X' is the trigger
+	 * and 'N' resolves to a numerical expression.
+	 */
+	case ('B'):
 		/* FALLTHROUGH */
-	case ('V'):
+	case ('h'):
 		/* FALLTHROUGH */
-	case ('$'):
+	case ('H'):
 		/* FALLTHROUGH */
-	case ('n'):
+	case ('L'):
 		/* FALLTHROUGH */
-#endif
-	case ('k'):
+	case ('l'):
 		/* FALLTHROUGH */
-	case ('M'):
+	case ('N'):
+		if (ESCAPE_ERROR == gly)
+			gly = ESCAPE_NUMBERED;
 		/* FALLTHROUGH */
-	case ('m'):
+	case ('S'):
 		/* FALLTHROUGH */
-	case ('f'):
+	case ('v'):
 		/* FALLTHROUGH */
-	case ('F'):
+	case ('w'):
 		/* FALLTHROUGH */
-	case ('*'):
-		switch (*p++) {
+	case ('x'):
+		if (ESCAPE_ERROR == gly)
+			gly = ESCAPE_IGNORE;
+		if ('\'' != cp[i++])
+			return(ESCAPE_ERROR);
+		term = numeric = '\'';
+		break;
+
+	/* 
+	 * Sizes get a special category of their own.
+	 */
+	case ('s'):
+		gly = ESCAPE_IGNORE;
+
+		rstart = &cp[i];
+		if (start) 
+			*start = rstart;
+
+		/* See +/- counts as a sign. */
+		c = cp[i];
+		if ('+' == c || '-' == c || ASCII_HYPH == c)
+			++i;
+
+		switch (cp[i++]) {
 		case ('('):
-			len = 2;
+			lim = 2;
 			break;
 		case ('['):
-			term = ']';
+			term = numeric = ']';
+			break;
+		case ('\''):
+			term = numeric = '\'';
 			break;
 		default:
-			len = 1;
-			p--;
+			lim = 1;
+			i--;
 			break;
 		}
+
+		/* See +/- counts as a sign. */
+		c = cp[i];
+		if ('+' == c || '-' == c || ASCII_HYPH == c)
+			++i;
+
 		break;
-	case ('('):
-		len = 2;
-		break;
-	case ('['):
-		term = ']';
-		break;
-	case ('z'):
-		len = 1;
-		if ('\\' == *p) {
-			if (0 == (i = mandoc_special(p)))
-				return(0);
-			p += i;
-			return(*p ? (int)(p - sv) : 0);
-		}
+
+	/*
+	 * Anything else is assumed to be a glyph.
+	 */
+	default:
+		gly = ESCAPE_SPECIAL;
+		lim = 1;
+		i--;
 		break;
-	case ('o'):
-		/* FALLTHROUGH */
-	case ('w'):
-		if ('\'' == *p++) {
-			term = '\'';
+	}
+
+	assert(ESCAPE_ERROR != gly);
+
+	rstart = &cp[i];
+	if (start)
+		*start = rstart;
+
+	/*
+	 * If a terminating block has been specified, we need to
+	 * handle the case of recursion, which could have their
+	 * own terminating blocks that mess up our parse.  This, by the
+	 * way, means that the "start" and "size" values will be
+	 * effectively meaningless.
+	 */
+
+	ssz = 0;
+	if (numeric && -1 == (ssz = numescape(&cp[i])))
+		return(ESCAPE_ERROR);
+
+	i += ssz;
+	rlim = -1;
+
+	/*
+	 * We have a character terminator.  Try to read up to that
+	 * character.  If we can't (i.e., we hit the nil), then return
+	 * an error; if we can, calculate our length, read past the
+	 * terminating character, and exit.
+	 */
+
+	if ('\0' != term) {
+		*end = strchr(&cp[i], term);
+		if ('\0' == *end)
+			return(ESCAPE_ERROR);
+
+		rlim = *end - &cp[i];
+		if (sz)
+			*sz = rlim;
+		(*end)++;
+		goto out;
+	}
+
+	assert(lim > 0);
+
+	/*
+	 * We have a numeric limit.  If the string is shorter than that,
+	 * stop and return an error.  Else adjust our endpoint, length,
+	 * and return the current glyph.
+	 */
+
+	if ((size_t)lim > strlen(&cp[i]))
+		return(ESCAPE_ERROR);
+
+	rlim = lim;
+	if (sz)
+		*sz = rlim;
+
+	*end = &cp[i] + lim;
+
+out:
+	assert(rlim >= 0 && rstart);
+
+	/* Run post-processors. */
+
+	switch (gly) {
+	case (ESCAPE_FONT):
+		if (1 != rlim)
+			break;
+		switch (*rstart) {
+		case ('3'):
+			/* FALLTHROUGH */
+		case ('B'):
+			gly = ESCAPE_FONTBOLD;
+			break;
+		case ('2'):
+			/* FALLTHROUGH */
+		case ('I'):
+			gly = ESCAPE_FONTITALIC;
+			break;
+		case ('P'):
+			gly = ESCAPE_FONTPREV;
+			break;
+		case ('1'):
+			/* FALLTHROUGH */
+		case ('R'):
+			gly = ESCAPE_FONTROMAN;
 			break;
 		}
-		/* FALLTHROUGH */
+	case (ESCAPE_SPECIAL):
+		if (1 != rlim)
+			break;
+		if ('c' == *rstart)
+			gly = ESCAPE_NOSPACE;
+		break;
 	default:
-		len = 1;
-		p--;
 		break;
 	}
 
-	if (term) {
-		for ( ; *p && term != *p; p++)
-			if (ASCII_HYPH == *p)
-				*p = '-';
-		return(*p ? (int)(p - sv) : 0);
-	}
-
-	for (i = 0; *p && i < len; i++, p++)
-		if (ASCII_HYPH == *p)
-			*p = '-';
-	return(i == len ? (int)(p - sv) : 0);
+	return(gly);
 }
-
 
 void *
 mandoc_calloc(size_t num, size_t size)
Index: mandoc.h
===================================================================
RCS file: /usr/vhosts/mdocml.bsd.lv/cvs/mdocml/mandoc.h,v
retrieving revision 1.69
diff -u -r1.69 mandoc.h
--- mandoc.h	28 Mar 2011 21:49:42 -0000	1.69
+++ mandoc.h	8 Apr 2011 13:54:21 -0000
@@ -288,6 +288,20 @@
 	MPARSE_MAN /* assume -man */
 };
 
+enum	mandoc_esc {
+	ESCAPE_ERROR = 0, /* bail! unparsable escape */
+	ESCAPE_IGNORE, /* escape to be ignored */
+	ESCAPE_SPECIAL, /* a regular special character */
+	ESCAPE_PREDEF, /* a predefined special character */
+	ESCAPE_FONT, /* a generic font mode */
+	ESCAPE_FONTBOLD, /* bold font mode */
+	ESCAPE_FONTITALIC, /* italic font mode */
+	ESCAPE_FONTROMAN, /* roman font mode */
+	ESCAPE_FONTPREV, /* previous font mode */
+	ESCAPE_NUMBERED, /* a numbered glyph */
+	ESCAPE_NOSPACE /* suppress space if the last on a line */
+};
+
 typedef	void	(*mandocmsg)(enum mandocerr, enum mandoclevel,
 			const char *, int, int, const char *);
 
@@ -309,6 +323,8 @@
 void		 *mandoc_calloc(size_t, size_t);
 void		 *mandoc_malloc(size_t);
 void		 *mandoc_realloc(void *, size_t);
+
+enum mandoc_esc	  mandoc_escape(const char **, const char **, int *);
 
 __END_DECLS
 
Index: mdoc_validate.c
===================================================================
RCS file: /usr/vhosts/mdocml.bsd.lv/cvs/mdocml/mdoc_validate.c,v
retrieving revision 1.166
diff -u -r1.166 mdoc_validate.c
--- mdoc_validate.c	3 Apr 2011 09:53:50 -0000	1.166
+++ mdoc_validate.c	8 Apr 2011 13:54:21 -0000
@@ -545,31 +545,39 @@
 static void
 check_text(struct mdoc *m, int ln, int pos, char *p)
 {
-	int		 c;
+	char		*cpp, *pp;
 	size_t		 sz;
 
-	for ( ; *p; p++, pos++) {
+	while ('\0' != *p) {
 		sz = strcspn(p, "\t\\");
-		p += (int)sz;
-
-		if ('\0' == *p)
-			break;
 
+		p += (int)sz;
 		pos += (int)sz;
 
 		if ('\t' == *p) {
 			if ( ! (MDOC_LITERAL & m->flags))
 				mdoc_pmsg(m, ln, pos, MANDOCERR_BADTAB);
+			p++;
+			pos++;
 			continue;
-		}
+		} else if ('\0' == *p)
+			break;
+
+		pos++;
+		pp = ++p;
 
-		if (0 == (c = mandoc_special(p))) {
+		if (ESCAPE_ERROR == mandoc_escape
+				((const char **)&pp, NULL, NULL)) {
 			mdoc_pmsg(m, ln, pos, MANDOCERR_BADESCAPE);
-			continue;
+			break;
 		}
 
-		p += c - 1;
-		pos += c - 1;
+		cpp = p;
+		while (NULL != (cpp = memchr(cpp, ASCII_HYPH, pp - cpp)))
+			*cpp = '-';
+
+		pos += pp - p;
+		p = pp;
 	}
 }
 
Index: out.c
===================================================================
RCS file: /usr/vhosts/mdocml.bsd.lv/cvs/mdocml/out.c,v
retrieving revision 1.39
diff -u -r1.39 out.c
--- out.c	17 Mar 2011 08:49:34 -0000	1.39
+++ out.c	8 Apr 2011 13:54:21 -0000
@@ -174,243 +174,6 @@
 	(void)strftime(p, sz, "%Y", &tm);
 }
 
-
-int
-a2roffdeco(enum roffdeco *d, const char **word, size_t *sz)
-{
-	int		 i, j, lim;
-	char		 term, c;
-	const char	*wp;
-	enum roffdeco	 dd;
-
-	*d = DECO_NONE;
-	lim = i = 0;
-	term = '\0';
-	wp = *word;
-
-	switch ((c = wp[i++])) {
-	case ('('):
-		*d = DECO_SPECIAL;
-		lim = 2;
-		break;
-	case ('F'):
-		/* FALLTHROUGH */
-	case ('f'):
-		*d = 'F' == c ? DECO_FFONT : DECO_FONT;
-
-		switch (wp[i++]) {
-		case ('('):
-			lim = 2;
-			break;
-		case ('['):
-			term = ']';
-			break;
-		case ('3'):
-			/* FALLTHROUGH */
-		case ('B'):
-			*d = DECO_BOLD;
-			return(i);
-		case ('2'):
-			/* FALLTHROUGH */
-		case ('I'):
-			*d = DECO_ITALIC;
-			return(i);
-		case ('P'):
-			*d = DECO_PREVIOUS;
-			return(i);
-		case ('1'):
-			/* FALLTHROUGH */
-		case ('R'):
-			*d = DECO_ROMAN;
-			return(i);
-		default:
-			i--;
-			lim = 1;
-			break;
-		}
-		break;
-	case ('k'):
-		/* FALLTHROUGH */
-	case ('M'):
-		/* FALLTHROUGH */
-	case ('m'):
-		/* FALLTHROUGH */
-	case ('*'):
-		if ('*' == c)
-			*d = DECO_RESERVED;
-
-		switch (wp[i++]) {
-		case ('('):
-			lim = 2;
-			break;
-		case ('['):
-			term = ']';
-			break;
-		default:
-			i--;
-			lim = 1;
-			break;
-		}
-		break;
-
-	case ('N'):
-
-		/*
-		 * Sequence of characters:  backslash,  'N' (i = 0),
-		 * starting delimiter (i = 1), character number (i = 2).
-		 */
-
-		*word = wp + 2;
-		*sz = 0;
-
-		/*
-		 * Cannot use a digit as a starting delimiter;
-		 * but skip the digit anyway.
-		 */
-
-		if (isdigit((int)wp[1]))
-			return(2);
-
-		/*
-		 * Any non-digit terminates the character number.
-		 * That is, the terminating delimiter need not
-		 * match the starting delimiter.
-		 */
-
-		for (i = 2; isdigit((int)wp[i]); i++)
-			(*sz)++;
-
-		/*
-		 * This is only a numbered character
-		 * if the character number has at least one digit.
-		 */
-
-		if (*sz)
-			*d = DECO_NUMBERED;
-
-		/*
-		 * Skip the terminating delimiter, even if it does not
-		 * match, and even if there is no character number.
-		 */
-
-		return(++i);
-
-	case ('h'):
-		/* FALLTHROUGH */
-	case ('v'):
-		/* FALLTHROUGH */
-	case ('s'):
-		j = 0;
-		if ('+' == wp[i] || '-' == wp[i]) {
-			i++;
-			j = 1;
-		}
-
-		switch (wp[i++]) {
-		case ('('):
-			lim = 2;
-			break;
-		case ('['):
-			term = ']';
-			break;
-		case ('\''):
-			term = '\'';
-			break;
-		case ('0'):
-			j = 1;
-			/* FALLTHROUGH */
-		default:
-			i--;
-			lim = 1;
-			break;
-		}
-
-		if ('+' == wp[i] || '-' == wp[i]) {
-			if (j)
-				return(i);
-			i++;
-		} 
-
-		/* Handle embedded numerical subexp or escape. */
-
-		if ('(' == wp[i]) {
-			while (wp[i] && ')' != wp[i])
-				if ('\\' == wp[i++]) {
-					/* Handle embedded escape. */
-					*word = &wp[i];
-					i += a2roffdeco(&dd, word, sz);
-				}
-
-			if (')' == wp[i++])
-				break;
-
-			*d = DECO_NONE;
-			return(i - 1);
-		} else if ('\\' == wp[i]) {
-			*word = &wp[++i];
-			i += a2roffdeco(&dd, word, sz);
-		}
-
-		break;
-	case ('['):
-		*d = DECO_SPECIAL;
-		term = ']';
-		break;
-	case ('c'):
-		*d = DECO_NOSPACE;
-		return(i);
-	case ('z'):
-		*d = DECO_NONE;
-		if ('\\' == wp[i]) {
-			*word = &wp[++i];
-			return(i + a2roffdeco(&dd, word, sz));
-		} else
-			lim = 1;
-		break;
-	case ('o'):
-		/* FALLTHROUGH */
-	case ('w'):
-		if ('\'' == wp[i++]) {
-			term = '\'';
-			break;
-		} 
-		/* FALLTHROUGH */
-	default:
-		*d = DECO_SSPECIAL;
-		i--;
-		lim = 1;
-		break;
-	}
-
-	assert(term || lim);
-	*word = &wp[i];
-
-	if (term) {
-		j = i;
-		while (wp[i] && wp[i] != term)
-			i++;
-		if ('\0' == wp[i]) {
-			*d = DECO_NONE;
-			return(i);
-		}
-
-		assert(i >= j);
-		*sz = (size_t)(i - j);
-
-		return(i + 1);
-	}
-
-	assert(lim > 0);
-	*sz = (size_t)lim;
-
-	for (j = 0; wp[i] && j < lim; j++)
-		i++;
-	if (j < lim)
-		*d = DECO_NONE;
-
-	return(i);
-}
-
 /*
  * Calculate the abstract widths and decimal positions of columns in a
  * table.  This routine allocates the columns structures then runs over
Index: out.h
===================================================================
RCS file: /usr/vhosts/mdocml.bsd.lv/cvs/mdocml/out.h,v
retrieving revision 1.18
diff -u -r1.18 out.h
--- out.h	22 Mar 2011 10:13:01 -0000	1.18
+++ out.h	8 Apr 2011 13:54:21 -0000
@@ -31,22 +31,6 @@
 	SCALE_MAX
 };
 
-enum	roffdeco {
-	DECO_NONE,
-	DECO_NUMBERED, /* numbered character */
-	DECO_SPECIAL, /* special character */
-	DECO_SSPECIAL, /* single-char special */
-	DECO_RESERVED, /* reserved word */
-	DECO_BOLD, /* bold font */
-	DECO_ITALIC, /* italic font */
-	DECO_ROMAN, /* "normal" undecorated font */
-	DECO_PREVIOUS, /* revert to previous font */
-	DECO_NOSPACE, /* suppress spacing */
-	DECO_FONT, /* font */
-	DECO_FFONT, /* font family */
-	DECO_MAX
-};
-
 enum	chars {
 	CHARS_ASCII, /* 7-bit ascii representation */
 	CHARS_HTML /* unicode values */
@@ -85,7 +69,6 @@
 	while (/* CONSTCOND */ 0)
 
 int	  	  a2roffsu(const char *, struct roffsu *, enum roffscale);
-int	  	  a2roffdeco(enum roffdeco *, const char **, size_t *);
 void	  	  time2a(time_t, char *, size_t);
 void	  	  tblcalc(struct rofftbl *tbl, const struct tbl_span *);
 
Index: read.c
===================================================================
RCS file: /usr/vhosts/mdocml.bsd.lv/cvs/mdocml/read.c,v
retrieving revision 1.11
diff -u -r1.11 read.c
--- read.c	4 Apr 2011 23:04:38 -0000	1.11
+++ read.c	8 Apr 2011 13:54:21 -0000
@@ -142,7 +142,7 @@
 	"tab in non-literal context",
 	"end of line whitespace",
 	"bad comment style",
-	"unknown escape sequence",
+	"bad escape sequence",
 	"unterminated quoted string",
 	
 	"generic error",
Index: term.c
===================================================================
RCS file: /usr/vhosts/mdocml.bsd.lv/cvs/mdocml/term.c,v
retrieving revision 1.183
diff -u -r1.183 term.c
--- term.c	4 Apr 2011 21:14:12 -0000	1.183
+++ term.c	8 Apr 2011 13:54:21 -0000
@@ -33,8 +33,7 @@
 #include "term.h"
 #include "main.h"
 
-static	void		  spec(struct termp *, enum roffdeco,
-				const char *, size_t);
+static	void		  spec(struct termp *, const char *, size_t);
 static	void		  res(struct termp *, const char *, size_t);
 static	void		  bufferc(struct termp *, char);
 static	void		  adjbuf(struct termp *p, size_t);
@@ -358,7 +357,7 @@
 
 
 static void
-spec(struct termp *p, enum roffdeco d, const char *word, size_t len)
+spec(struct termp *p, const char *word, size_t len)
 {
 	const char	*rhs;
 	size_t		 sz;
@@ -366,7 +365,7 @@
 	rhs = chars_spec2str(p->symtab, word, len, &sz);
 	if (rhs) 
 		encode(p, rhs, sz);
-	else if (DECO_SSPECIAL == d)
+	else if (1 == len)
 		encode(p, word, len);
 }
 
@@ -457,8 +456,9 @@
 term_word(struct termp *p, const char *word)
 {
 	const char	*seq;
+	int		 sz;
 	size_t		 ssz;
-	enum roffdeco	 deco;
+	enum mandoc_esc	 esc;
 
 	if ( ! (TERMP_NOSPACE & p->flags)) {
 		if ( ! (TERMP_KEEP & p->flags)) {
@@ -478,7 +478,7 @@
 
 	p->flags &= ~(TERMP_SENTENCE | TERMP_IGNDELIM);
 
-	while (*word) {
+	while ('\0' != *word) {
 		if ((ssz = strcspn(word, "\\")) > 0)
 			encode(p, word, ssz);
 
@@ -486,39 +486,40 @@
 		if ('\\' != *word)
 			continue;
 
-		seq = ++word;
-		word += a2roffdeco(&deco, &seq, &ssz);
+		word++;
+		esc = mandoc_escape(&word, &seq, &sz);
+		if (ESCAPE_ERROR == esc)
+			break;
 
-		switch (deco) {
-		case (DECO_NUMBERED):
-			numbered(p, seq, ssz);
-			break;
-		case (DECO_RESERVED):
-			res(p, seq, ssz);
-			break;
-		case (DECO_SPECIAL):
-			/* FALLTHROUGH */
-		case (DECO_SSPECIAL):
-			spec(p, deco, seq, ssz);
+		switch (esc) {
+		case (ESCAPE_NUMBERED):
+			numbered(p, seq, sz);
+			break;
+		case (ESCAPE_PREDEF):
+			res(p, seq, sz);
+			break;
+		case (ESCAPE_SPECIAL):
+			spec(p, seq, sz);
 			break;
-		case (DECO_BOLD):
+		case (ESCAPE_FONTBOLD):
 			term_fontrepl(p, TERMFONT_BOLD);
 			break;
-		case (DECO_ITALIC):
+		case (ESCAPE_FONTITALIC):
 			term_fontrepl(p, TERMFONT_UNDER);
 			break;
-		case (DECO_ROMAN):
+		case (ESCAPE_FONTROMAN):
 			term_fontrepl(p, TERMFONT_NONE);
 			break;
-		case (DECO_PREVIOUS):
+		case (ESCAPE_FONTPREV):
 			term_fontlast(p);
 			break;
+		case (ESCAPE_NOSPACE):
+			if ('\0' == *word)
+				p->flags |= TERMP_NOSPACE;
+			break;
 		default:
 			break;
 		}
-
-		if (DECO_NOSPACE == deco && '\0' == *word)
-			p->flags |= TERMP_NOSPACE;
 	}
 }
 
@@ -600,33 +601,36 @@
 size_t
 term_strlen(const struct termp *p, const char *cp)
 {
-	size_t		 sz, ssz, rsz, i;
-	enum roffdeco	 d;
+	size_t		 sz, rsz, i;
+	int		 ssz;
+	enum mandoc_esc	 esc;
 	const char	*seq, *rhs;
 
-	for (sz = 0; '\0' != *cp; )
-		/*
-		 * Account for escaped sequences within string length
-		 * calculations.  This follows the logic in term_word()
-		 * as we must calculate the width of produced strings.
-		 */
-		if ('\\' == *cp) {
-			seq = ++cp;
-			cp += a2roffdeco(&d, &seq, &ssz);
+	/*
+	 * Account for escaped sequences within string length
+	 * calculations.  This follows the logic in term_word() as we
+	 * must calculate the width of produced strings.
+	 */
+
+	sz = 0;
+	while ('\0' != *cp)
+		switch (*cp) {
+		case ('\\'):
+			++cp;
+			esc = mandoc_escape(&cp, &seq, &ssz);
+			if (ESCAPE_ERROR == esc)
+				return(sz);
 
-			switch (d) {
-			case (DECO_RESERVED):
+			switch (esc) {
+			case (ESCAPE_PREDEF):
 				rhs = chars_res2str
 					(p->symtab, seq, ssz, &rsz);
 				break;
-			case (DECO_SPECIAL):
-				/* FALLTHROUGH */
-			case (DECO_SSPECIAL):
+			case (ESCAPE_SPECIAL):
 				rhs = chars_spec2str
 					(p->symtab, seq, ssz, &rsz);
 
-				/* Allow for one-char escapes. */
-				if (DECO_SSPECIAL != d || rhs)
+				if (ssz != 1 || rhs)
 					break;
 
 				rhs = seq;
@@ -637,17 +641,24 @@
 				break;
 			}
 
-			if (rhs)
-				for (i = 0; i < rsz; i++)
-					sz += (*p->width)(p, *rhs++);
-		} else if (ASCII_NBRSP == *cp) {
+			if (NULL == rhs)
+				break;
+
+			for (i = 0; i < rsz; i++)
+				sz += (*p->width)(p, *rhs++);
+			break;
+		case (ASCII_NBRSP):
 			sz += (*p->width)(p, ' ');
 			cp++;
-		} else if (ASCII_HYPH == *cp) {
+			break;
+		case (ASCII_HYPH):
 			sz += (*p->width)(p, '-');
 			cp++;
-		} else
+			break;
+		default:
 			sz += (*p->width)(p, *cp++);
+			break;
+		}
 
 	return(sz);
 }