diff --git a/qse/cmd/awk/awk.c b/qse/cmd/awk/awk.c
index fcbfc9d4..73efded2 100644
--- a/qse/cmd/awk/awk.c
+++ b/qse/cmd/awk/awk.c
@@ -1,5 +1,5 @@
 /*
- * $Id: awk.c 291 2009-09-21 13:28:18Z hyunghwan.chung $
+ * $Id: awk.c 306 2009-11-22 13:58:53Z hyunghwan.chung $
  *
     Copyright 2006-2009 Chung, Hyung-Hwan.
     This file is part of QSE.
@@ -297,11 +297,7 @@ static int fnc_sleep (qse_awk_rtx_t* run, const qse_cstr_t* fnm)
 #endif
 
 	r = qse_awk_rtx_makeintval (run, n);
-	if (r == QSE_NULL)
-	{
-		qse_awk_rtx_seterrnum (run, QSE_AWK_ENOMEM, QSE_NULL);
-		return -1;
-	}
+	if (r == QSE_NULL) return -1;
 
 	qse_awk_rtx_setretval (run, r);
 	return 0;
diff --git a/qse/configure b/qse/configure
index 9aafb2c2..5554ec09 100755
--- a/qse/configure
+++ b/qse/configure
@@ -1,6 +1,6 @@
 #! /bin/sh
 # Guess values for system-dependent variables and create Makefiles.
-# Generated by GNU Autoconf 2.64 for qse 0.5.2.
+# Generated by GNU Autoconf 2.64 for qse 0.5.3.
 #
 # Report bugs to <bacon@abiyo.net>.
 #
@@ -698,8 +698,8 @@ MAKEFLAGS=
 # Identity of this package.
 PACKAGE_NAME='qse'
 PACKAGE_TARNAME='qse'
-PACKAGE_VERSION='0.5.2'
-PACKAGE_STRING='qse 0.5.2'
+PACKAGE_VERSION='0.5.3'
+PACKAGE_STRING='qse 0.5.3'
 PACKAGE_BUGREPORT='bacon@abiyo.net'
 PACKAGE_URL=''
 
@@ -1457,7 +1457,7 @@ if test "$ac_init_help" = "long"; then
   # Omit some internal or obsolete options to make the list less imposing.
   # This message is too long to be a string in the A/UX 3.1 sh.
   cat <<_ACEOF
-\`configure' configures qse 0.5.2 to adapt to many kinds of systems.
+\`configure' configures qse 0.5.3 to adapt to many kinds of systems.
 
 Usage: $0 [OPTION]... [VAR=VALUE]...
 
@@ -1527,7 +1527,7 @@ fi
 
 if test -n "$ac_init_help"; then
   case $ac_init_help in
-     short | recursive ) echo "Configuration of qse 0.5.2:";;
+     short | recursive ) echo "Configuration of qse 0.5.3:";;
    esac
   cat <<\_ACEOF
 
@@ -1641,7 +1641,7 @@ fi
 test -n "$ac_init_help" && exit $ac_status
 if $ac_init_version; then
   cat <<\_ACEOF
-qse configure 0.5.2
+qse configure 0.5.3
 generated by GNU Autoconf 2.64
 
 Copyright (C) 2009 Free Software Foundation, Inc.
@@ -2403,7 +2403,7 @@ cat >config.log <<_ACEOF
 This file contains any messages produced by compilers while
 running configure, to aid debugging if configure makes a mistake.
 
-It was created by qse $as_me 0.5.2, which was
+It was created by qse $as_me 0.5.3, which was
 generated by GNU Autoconf 2.64.  Invocation command line was
 
   $ $0 $@
@@ -3222,7 +3222,7 @@ fi
 
 # Define the identity of the package.
  PACKAGE='qse'
- VERSION='0.5.2'
+ VERSION='0.5.3'
 
 
 cat >>confdefs.h <<_ACEOF
@@ -17992,7 +17992,7 @@ cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
 # report actual input values of CONFIG_FILES etc. instead of their
 # values after options handling.
 ac_log="
-This file was extended by qse $as_me 0.5.2, which was
+This file was extended by qse $as_me 0.5.3, which was
 generated by GNU Autoconf 2.64.  Invocation command line was
 
   CONFIG_FILES    = $CONFIG_FILES
@@ -18056,7 +18056,7 @@ Report bugs to <bacon@abiyo.net>."
 _ACEOF
 cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
 ac_cs_version="\\
-qse config.status 0.5.2
+qse config.status 0.5.3
 configured by $0, generated by GNU Autoconf 2.64,
   with options \\"`$as_echo "$ac_configure_args" | sed 's/^ //; s/[\\""\`\$]/\\\\&/g'`\\"
 
diff --git a/qse/configure.ac b/qse/configure.ac
index 513f0156..931ff700 100644
--- a/qse/configure.ac
+++ b/qse/configure.ac
@@ -1,5 +1,5 @@
 dnl AC_PREREQ(2.59)
-AC_INIT([qse],[0.5.2],[bacon@abiyo.net])
+AC_INIT([qse],[0.5.3],[bacon@abiyo.net])
 AC_CONFIG_HEADER([include/qse/config.h])
 AC_CONFIG_AUX_DIR([ac/au])
 AC_CONFIG_MACRO_DIR([ac/m4])
diff --git a/qse/include/qse/awk/awk.h b/qse/include/qse/awk/awk.h
index 3bfb41e6..ebd65238 100644
--- a/qse/include/qse/awk/awk.h
+++ b/qse/include/qse/awk/awk.h
@@ -1,5 +1,5 @@
 /*
- * $Id: awk.h 299 2009-10-19 13:33:40Z hyunghwan.chung $
+ * $Id: awk.h 306 2009-11-22 13:58:53Z hyunghwan.chung $
  *
     Copyright 2006-2009 Chung, Hyung-Hwan.
     This file is part of QSE.
@@ -795,7 +795,7 @@ enum qse_awk_errnum_t
 	QSE_AWK_EREXCOLON,     /**< a colon is expected */
 	QSE_AWK_EREXCRANGE,    /**< invalid character range */
 	QSE_AWK_EREXCCLASS,    /**< invalid character class */
-	QSE_AWK_EREXBRANGE,    /**< invalid boundary range */
+	QSE_AWK_EREXBOUND,     /**< invalid boundary range */
 	QSE_AWK_EREXEND,       /**< unexpected end of the pattern */
 	QSE_AWK_EREXGARBAGE,   /**< garbage after the pattern */
 
diff --git a/qse/include/qse/cmn/rex.h b/qse/include/qse/cmn/rex.h
index 7d8c0f2f..174663cf 100644
--- a/qse/include/qse/cmn/rex.h
+++ b/qse/include/qse/cmn/rex.h
@@ -1,5 +1,5 @@
 /*
- * $Id: rex.h 304 2009-11-20 05:12:27Z hyunghwan.chung $
+ * $Id: rex.h 306 2009-11-22 13:58:53Z hyunghwan.chung $
  *
     Copyright 2006-2009 Chung, Hyung-Hwan.
     This file is part of QSE.
@@ -72,6 +72,10 @@ enum qse_rex_option_t
 	/**< do not support the {n,m} style occurrence specifier */
 	QSE_REX_NOBOUND = (1 << 0),
 
+	QSE_REX_ESQ_HEX   = (1 << 1), /* \xhh and \uhhhh */
+	QSE_REX_ESQ_OCTAL = (1 << 2), /* \000 */
+	QSE_REX_ESQ_CNTRL = (1 << 3), /* \cX where X is A to Z */
+
 	/**< perform case-insensitive match */
 	QSE_REX_IGNORECASE = (1 << 8)
 };
@@ -89,7 +93,7 @@ enum qse_rex_errnum_t
         QSE_REX_ECOLON,        /* a colon is expected */
         QSE_REX_ECRANGE,       /* invalid character range */
         QSE_REX_ECCLASS,       /* invalid character class */
-        QSE_REX_EBRANGE,       /* invalid boundary range */
+        QSE_REX_EBOUND,        /* invalid boundary range */
         QSE_REX_EEND,          /* unexpected end of the pattern */
         QSE_REX_EGARBAGE       /* garbage after the pattern */
 };
diff --git a/qse/lib/awk/misc.c b/qse/lib/awk/misc.c
index 0c8a6146..b2e7db2a 100644
--- a/qse/lib/awk/misc.c
+++ b/qse/lib/awk/misc.c
@@ -1,5 +1,5 @@
 /*
- * $Id: misc.c 292 2009-09-23 10:19:30Z hyunghwan.chung $
+ * $Id: misc.c 306 2009-11-22 13:58:53Z hyunghwan.chung $
  *
     Copyright 2006-2009 Chung, Hyung-Hwan.
     This file is part of QSE.
@@ -1039,7 +1039,7 @@ qse_char_t* qse_awk_rtx_strxnfld (
 	 (err == QSE_REX_ECOLON)?      QSE_AWK_EREXCOLON: \
 	 (err == QSE_REX_ECRANGE)?     QSE_AWK_EREXCRANGE: \
 	 (err == QSE_REX_ECCLASS)?     QSE_AWK_EREXCCLASS: \
-	 (err == QSE_REX_EBRANGE)?     QSE_AWK_EREXBRANGE: \
+	 (err == QSE_REX_EBOUND)?      QSE_AWK_EREXBOUND: \
 	 (err == QSE_REX_EEND)?        QSE_AWK_EREXEND: \
 	 (err == QSE_REX_EGARBAGE)?    QSE_AWK_EREXGARBAGE: \
 	                               QSE_AWK_EINTERN)
diff --git a/qse/lib/awk/std.c b/qse/lib/awk/std.c
index 8cf3e4ef..494ed77b 100644
--- a/qse/lib/awk/std.c
+++ b/qse/lib/awk/std.c
@@ -1,5 +1,5 @@
 /*
- * $Id: std.c 291 2009-09-21 13:28:18Z hyunghwan.chung $
+ * $Id: std.c 306 2009-11-22 13:58:53Z hyunghwan.chung $
  *
     Copyright 2006-2009 Chung, Hyung-Hwan.
     This file is part of QSE.
@@ -1224,11 +1224,7 @@ static int fnc_math_1 (
 		r = qse_awk_rtx_makerealval (run, rf(rv));
 	}
 	
-	if (r == QSE_NULL)
-	{
-		qse_awk_rtx_seterrnum (run, QSE_AWK_ENOMEM, QSE_NULL);
-		return -1;
-	}
+	if (r == QSE_NULL) return -1;
 
 	qse_awk_rtx_setretval (run, r);
 	return 0;
@@ -1277,11 +1273,7 @@ static int fnc_math_2 (
 		r = qse_awk_rtx_makerealval (run, rf(rv0,rv1));
 	}
 	
-	if (r == QSE_NULL)
-	{
-		qse_awk_rtx_seterrnum (run, QSE_AWK_ENOMEM, QSE_NULL);
-		return -1;
-	}
+	if (r == QSE_NULL) return -1;
 
 	qse_awk_rtx_setretval (run, r);
 	return 0;
@@ -1434,11 +1426,7 @@ static int fnc_int (qse_awk_rtx_t* run, const qse_cstr_t* fnm)
 	if (n == 1) lv = (qse_long_t)rv;
 
 	r = qse_awk_rtx_makeintval (run, lv);
-	if (r == QSE_NULL)
-	{
-		qse_awk_rtx_seterrnum (run, QSE_AWK_ENOMEM, QSE_NULL);
-		return -1;
-	}
+	if (r == QSE_NULL) return -1;
 
 	qse_awk_rtx_setretval (run, r);
 	return 0;
@@ -1456,11 +1444,7 @@ static int fnc_rand (qse_awk_rtx_t* run, const qse_cstr_t* fnm)
 	*/
 	r = qse_awk_rtx_makerealval (
 		run, (qse_real_t)(rand() % RAND_MAX) / RAND_MAX);
-	if (r == QSE_NULL)
-	{
-		qse_awk_rtx_seterrnum (run, QSE_AWK_ENOMEM, QSE_NULL);
-		return -1;
-	}
+	if (r == QSE_NULL) return -1;
 
 	qse_awk_rtx_setretval (run, r);
 	return 0;
@@ -1504,11 +1488,7 @@ static int fnc_srand (qse_awk_rtx_t* run, const qse_cstr_t* fnm)
         srand (rxtn->seed);
 
 	r = qse_awk_rtx_makeintval (run, prev);
-	if (r == QSE_NULL)
-	{
-		qse_awk_rtx_seterrnum (run, QSE_AWK_ENOMEM, QSE_NULL);
-		return -1;
-	}
+	if (r == QSE_NULL) return -1;
 
 	qse_awk_rtx_setretval (run, r);
 	return 0;
diff --git a/qse/lib/cmn/rex.c b/qse/lib/cmn/rex.c
index e2616ad8..6baf61a0 100644
--- a/qse/lib/cmn/rex.c
+++ b/qse/lib/cmn/rex.c
@@ -1,5 +1,5 @@
 /*
- * $Id: rex.c 304 2009-11-20 05:12:27Z hyunghwan.chung $
+ * $Id: rex.c 306 2009-11-22 13:58:53Z hyunghwan.chung $
  * 
     Copyright 2006-2009 Chung, Hyung-Hwan.
     This file is part of QSE.
@@ -962,7 +962,7 @@ what if it is not in the raight format? convert it to ordinary characters?? */
 	if (cmd->lbound > cmd->ubound)
 	{
 		/* invalid occurrences range */
-		builder->errnum = QSE_REX_EBRANGE;
+		builder->errnum = QSE_REX_EBOUND;
 		return -1;
 	}
 
diff --git a/qse/lib/cmn/rex1.c b/qse/lib/cmn/rex1.c
index 55b1d713..4d43c29b 100644
--- a/qse/lib/cmn/rex1.c
+++ b/qse/lib/cmn/rex1.c
@@ -144,8 +144,8 @@ static void freenode (qse_rex_node_t* node, qse_mmgr_t* mmgr)
 {
 	if (node->id == QSE_REX_NODE_CHARSET)
 	{
-		// TODO: 
-		QSE_MMGR_FREE (mmgr, node->u.cs);
+		if (node->u.cs != QSE_NULL) 
+			QSE_MMGR_FREE (mmgr, node->u.cs);
 	}
 
 	QSE_MMGR_FREE (mmgr, node);
@@ -288,8 +288,13 @@ static qse_rex_node_t* newbranchnode (
 #define IS_ESC(com) ((com)->c.escaped)
 #define IS_EOF(com) ((com)->c.value == QSE_CHAR_EOF)
 
-static int getc (comp_t* com)
+#define getc_noesc(c) getc(c,1)
+#define getc_esc(c)   getc(c,0)
+
+static int getc (comp_t* com, int noesc)
 {
+	qse_char_t c;
+
 	if (com->ptr >= com->end)
 	{
 		com->c.value = QSE_CHAR_EOF;
@@ -298,110 +303,108 @@ static int getc (comp_t* com)
 	}
 
 	com->c.value = *com->ptr++;
-	com->c.escaped = QSE_FALSE;
+	com->c.escaped = 0;
 
-	if (com->c.value == QSE_T('\\'))
-	{	       
-		qse_char_t c;
+	if (noesc || com->c.value != QSE_T('\\')) return 0;
+
+
+	CHECK_END (com);
+	c = *com->ptr++;
+
+	if (c == QSE_T('n')) c = QSE_T('\n');
+	else if (c == QSE_T('r')) c = QSE_T('\r');
+	else if (c == QSE_T('t')) c = QSE_T('\t');
+	else if (c == QSE_T('f')) c = QSE_T('\f');
+	else if (c == QSE_T('b')) c = QSE_T('\b');
+	else if (c == QSE_T('v')) c = QSE_T('\v');
+	else if (c == QSE_T('a')) c = QSE_T('\a');
+	else if (c >= QSE_T('0') && c <= QSE_T('7')) 
+	{
+		qse_char_t cx;
+
+		c = c - QSE_T('0');
 
 		CHECK_END (com);
-		c = *com->ptr++;
-
-		if (c == QSE_T('n')) c = QSE_T('\n');
-		else if (c == QSE_T('r')) c = QSE_T('\r');
-		else if (c == QSE_T('t')) c = QSE_T('\t');
-		else if (c == QSE_T('f')) c = QSE_T('\f');
-		else if (c == QSE_T('b')) c = QSE_T('\b');
-		else if (c == QSE_T('v')) c = QSE_T('\v');
-		else if (c == QSE_T('a')) c = QSE_T('\a');
-		else if (c >= QSE_T('0') && c <= QSE_T('7')) 
+		cx = *com->ptr++;
+		if (cx >= QSE_T('0') && cx <= QSE_T('7'))
 		{
-			qse_char_t cx;
-
-			c = c - QSE_T('0');
+			c = c * 8 + cx - QSE_T('0');
 
 			CHECK_END (com);
 			cx = *com->ptr++;
 			if (cx >= QSE_T('0') && cx <= QSE_T('7'))
 			{
 				c = c * 8 + cx - QSE_T('0');
-
-				CHECK_END (com);
-				cx = *com->ptr++;
-				if (cx >= QSE_T('0') && cx <= QSE_T('7'))
-				{
-					c = c * 8 + cx - QSE_T('0');
-				}
 			}
 		}
-		else if (c == QSE_T('x')) 
-		{
-			qse_char_t cx;
-
-			CHECK_END (com);
-			cx = *com->ptr++;
-			if (IS_HEX(cx))
-			{
-				c = HEX_TO_NUM(cx);
-
-				CHECK_END (com);
-				cx = *com->ptr++;
-				if (IS_HEX(cx))
-				{
-					c = c * 16 + HEX_TO_NUM(cx);
-				}
-			}
-		}
-	#ifdef QSE_CHAR_IS_WCHAR
-		else if (c == QSE_T('u') && QSE_SIZEOF(qse_char_t) >= 2) 
-		{
-			qse_char_t cx;
-
-			CHECK_END (com);
-			cx = *com->ptr++;
-			if (IS_HEX(cx))
-			{
-				qse_size_t i;
-
-				c = HEX_TO_NUM(cx);
-
-				for (i = 0; i < 3; i++)
-				{
-					CHECK_END (com);
-					cx = *com->ptr++;
-
-					if (!IS_HEX(cx)) break;
-					c = c * 16 + HEX_TO_NUM(cx);
-				}
-			}
-		}
-		else if (c == QSE_T('U') && QSE_SIZEOF(qse_char_t) >= 4) 
-		{
-			qse_char_t cx;
-
-			CHECK_END (com);
-			cx = *com->ptr++;
-			if (IS_HEX(cx))
-			{
-				qse_size_t i;
-
-				c = HEX_TO_NUM(cx);
-
-				for (i = 0; i < 7; i++)
-				{
-					CHECK_END (com);
-					cx = *com->ptr++;
-
-					if (!IS_HEX(cx)) break;
-					c = c * 16 + HEX_TO_NUM(cx);
-				}
-			}
-		}
-	#endif
-
-		com->c.value = c;
-		com->c.escaped = QSE_TRUE;
 	}
+	else if (c == QSE_T('x')) 
+	{
+		qse_char_t cx;
+
+		CHECK_END (com);
+		cx = *com->ptr++;
+		if (IS_HEX(cx))
+		{
+			c = HEX_TO_NUM(cx);
+
+			CHECK_END (com);
+			cx = *com->ptr++;
+			if (IS_HEX(cx))
+			{
+				c = c * 16 + HEX_TO_NUM(cx);
+			}
+		}
+	}
+#ifdef QSE_CHAR_IS_WCHAR
+	else if (c == QSE_T('u') && QSE_SIZEOF(qse_char_t) >= 2) 
+	{
+		qse_char_t cx;
+
+		CHECK_END (com);
+		cx = *com->ptr++;
+		if (IS_HEX(cx))
+		{
+			qse_size_t i;
+
+			c = HEX_TO_NUM(cx);
+
+			for (i = 0; i < 3; i++)
+			{
+				CHECK_END (com);
+				cx = *com->ptr++;
+
+				if (!IS_HEX(cx)) break;
+				c = c * 16 + HEX_TO_NUM(cx);
+			}
+		}
+	}
+	else if (c == QSE_T('U') && QSE_SIZEOF(qse_char_t) >= 4) 
+	{
+		qse_char_t cx;
+
+		CHECK_END (com);
+		cx = *com->ptr++;
+		if (IS_HEX(cx))
+		{
+			qse_size_t i;
+
+			c = HEX_TO_NUM(cx);
+
+			for (i = 0; i < 7; i++)
+			{
+				CHECK_END (com);
+				cx = *com->ptr++;
+
+				if (!IS_HEX(cx)) break;
+				c = c * 16 + HEX_TO_NUM(cx);
+			}
+		}
+	}
+#endif
+
+	com->c.value = c;
+	com->c.escaped = QSE_TRUE;
 
 #if 0
 	com->c = (com->ptr < com->end)? *com->ptr++: QSE_CHAR_EOF;
@@ -412,6 +415,162 @@ else qse_printf (QSE_T("getc => %c\n"), com->c);
 	return 0;
 }
 
+#if 0
+static int charclass (comp_t* builder, qse_char_t* cc)
+{
+	const struct __char_class_t* ccp = __char_class;
+	qse_size_t len = builder->ptn.end - builder->ptn.curp;
+
+	while (ccp->name != QSE_NULL)
+	{
+		if (__begin_with (builder->ptn.curp, len, ccp->name)) break;
+		ccp++;
+	}
+
+	if (ccp->name == QSE_NULL)
+	{
+		/* wrong class name */
+	#ifdef DEBUG_REX
+		DPUTS (QSE_T("build_atom_cclass: wrong class name\n"));
+	#endif
+		builder->errnum = QSE_REX_ECCLASS;
+		return -1;
+	}
+
+	builder->ptn.curp += ccp->name_len;
+
+	NEXT_CHAR (builder, LEVEL_CHARSET);
+	if (builder->ptn.curc.type != CT_NORMAL ||
+	    builder->ptn.curc.value != QSE_T(':'))
+	{
+	#ifdef DEBUG_REX
+		DPUTS (QSE_T("build_atom_cclass: a colon(:) expected\n"));
+	#endif
+		builder->errnum = QSE_REX_ECOLON;
+		return -1;
+	}
+
+	NEXT_CHAR (builder, LEVEL_CHARSET); 
+	
+	/* ] happens to be the charset ender ] */
+	if (builder->ptn.curc.type != CT_SPECIAL ||
+	    builder->ptn.curc.value != QSE_T(']'))
+	{
+	#ifdef DEBUG_REX
+		DPUTS (QSE_T("build_atom_cclass: ] expected\n"));
+	#endif
+		builder->errnum = QSE_REX_ERBRACKET;	
+		return -1;
+	}
+
+	NEXT_CHAR (builder, LEVEL_CHARSET);
+
+	*cc = (qse_char_t)(ccp - __char_class);
+	return 1;
+}
+#endif
+
+static int charset (comp_t* c, qse_rex_node_t* node)
+{
+	qse_size_t zero = 0;
+	qse_size_t old_size;
+	qse_size_t pos_csc;
+
+	if (c->c.value == QSE_T('^'))
+	{
+		//cmd->negate = 1;
+		//TODO: negate...
+		if (getc_noesc(c) <= -1) return -1;
+	}
+
+	/* if ] is the first character or the second character following ^,
+	 * it is treated literally */
+
+	do
+	{
+		qse_char_t c1, c2;
+
+		c1 = c->c.value;
+		if (getc_noesc(c) <= -1) return -1;
+		c2 = c->c.value;
+
+		if (c1 == QSE_T('[') && c2 == QSE_T(':'))
+		{
+			/* begins with [: */
+			if (getc_noesc(c) <= -1) return -1;
+			//if (charclass (c) <= -1) return -1;
+		}
+		else if (c2 == QSE_T('-'))
+		{
+			if (getc_noesc(c) <= -1) return -1;
+			//add c->c.value;
+qse_printf (QSE_T("[%c-%c]\n"), c1, c->c.value);
+			if (getc_noesc(c) <= -1) return -1;
+		}
+		else
+		{
+			//add c1;
+qse_printf (QSE_T("[%c]\n"), c1);
+		}
+	}
+	while (c->c.value != QSE_T(']'));
+
+	if (getc_esc(c) <= -1) return -1;
+	return 0;
+}
+
+static int occbound (comp_t* c, qse_rex_node_t* n)
+{
+	qse_size_t bound;
+
+	bound = 0;
+	while (c->c.value >= QSE_T('0') && c->c.value <= QSE_T('9'))
+	{
+		bound = bound * 10 + c->c.value - QSE_T('0');
+		if (getc_noesc(c) <= -1) return -1;
+	}
+
+	n->occ.min = bound;
+
+	if (c->c.value == QSE_T(',')) 
+	{
+		if (getc_noesc(c) <= -1) return -1;
+
+		if (c->c.value >= QSE_T('0') && c->c.value <= QSE_T('9'))
+		{
+			bound = 0;
+
+			do
+			{
+				bound = bound * 10 + c->c.value - QSE_T('0');
+				if (getc_noesc(c) <= -1) return -1;
+			}
+			while (c->c.value >= QSE_T('0') && 
+			       c->c.value <= QSE_T('9'));
+
+			n->occ.max = bound;
+		}
+		else n->occ.max = OCC_MAX;
+	}
+	else n->occ.max = n->occ.min;
+
+	if (n->occ.min > n->occ.min)
+	{
+		/* invalid occurrences range */
+		c->rex->errnum = QSE_REX_EBOUND;
+		return -1;
+	}
+
+	if (c->c.value != QSE_T('}'))
+	{
+		c->rex->errnum = QSE_REX_ERBRACE;
+		return -1;
+	}
+
+	if (getc_esc(c) <= -1) return -1;
+	return 0;
+}
+
 static qse_rex_node_t* comp0 (comp_t* c, qse_rex_node_t* ge);
 
 static qse_rex_node_t* comp2 (comp_t* c)
@@ -434,7 +593,7 @@ static qse_rex_node_t* comp2 (comp_t* c)
 				ge = newgroupendnode (c, n);
 				if (ge == QSE_NULL) return QSE_NULL;
 
-				if (getc(c) <= -1) return QSE_NULL;
+				if (getc_esc(c) <= -1) return QSE_NULL;
 
 				c->gdepth++;
 				x = comp0 (c, ge);
@@ -442,12 +601,12 @@ static qse_rex_node_t* comp2 (comp_t* c)
 
 				if (!IS_SPE(c,QSE_T(')')))
 				{
-					c->rex->errnum = QSE_REX_EUNBALPAREN;
+					c->rex->errnum = QSE_REX_ERPAREN;
 					return QSE_NULL;
 				}
 
 				c->gdepth--;
-				if (getc(c) <= -1) return QSE_NULL;
+				if (getc_esc(c) <= -1) return QSE_NULL;
 
 				n->u.g.head = x;
 				break;
@@ -457,26 +616,28 @@ static qse_rex_node_t* comp2 (comp_t* c)
 			case QSE_T('.'):
 				n = newnode (c, QSE_REX_NODE_ANYCHAR);
 				if (n == QSE_NULL) return QSE_NULL;
-				if (getc(c) <= -1) return QSE_NULL;
+				if (getc_esc(c) <= -1) return QSE_NULL;
 				break;
 
 			case QSE_T('^'):
 				n = newnode (c, QSE_REX_NODE_BOL);
 				if (n == QSE_NULL) return QSE_NULL;
-				if (getc(c) <= -1) return QSE_NULL;
+				if (getc_esc(c) <= -1) return QSE_NULL;
 				break;
 	
 			case QSE_T('$'):
 				n = newnode (c, QSE_REX_NODE_EOL);
 				if (n == QSE_NULL) return QSE_NULL;
-				if (getc(c) <= -1) return QSE_NULL;
+				if (getc_esc(c) <= -1) return QSE_NULL;
 				break;
 
-
-			/*
 			case QSE_T('['):
+				n = newnode (c, QSE_REX_NODE_CHARSET);
+				if (n == QSE_NULL) return QSE_NULL;
+
+				if (getc_noesc(c) <= -1) return QSE_NULL;
+				if (charset(c, n) <= -1) return QSE_NULL;
 				break;
-			*/
 
 			default:
 				goto normal_char;
@@ -488,7 +649,7 @@ static qse_rex_node_t* comp2 (comp_t* c)
 		/* normal character */
 		n = newcharnode (c, c->c.value);
 		if (n == QSE_NULL) return QSE_NULL;
-		if (getc(c) <= -1) return QSE_NULL;
+		if (getc_esc(c) <= -1) return QSE_NULL;
 	}
 
 	n->occ.min = 1;
@@ -503,30 +664,28 @@ static qse_rex_node_t* comp2 (comp_t* c)
 			case QSE_T('?'):
 				n->occ.min = 0;
 				n->occ.max = 1;
-				if (getc(c) <= -1) return QSE_NULL;
+				if (getc_esc(c) <= -1) return QSE_NULL;
 				break;
 			
 			case QSE_T('*'):
 				n->occ.min = 0;
 				n->occ.max = OCC_MAX;
-				if (getc(c) <= -1) return QSE_NULL;
+				if (getc_esc(c) <= -1) return QSE_NULL;
 				break;
 
 			case QSE_T('+'):
 				n->occ.min = 1;
 				n->occ.max = OCC_MAX;
-				if (getc(c) <= -1) return QSE_NULL;
+				if (getc_esc(c) <= -1) return QSE_NULL;
 				break;
 
-			/*
 			case QSE_T('{'):
-				// TODO:
-				if (!(com->rex->option & QSE_REX_NOBOUND))
+				if (!(c->rex->option & QSE_REX_NOBOUND))
 				{
+					if (getc_noesc(c) <= -1) return QSE_NULL;
+					if (occbound(c,n) <= -1) return QSE_NULL;
 				}
 				break;
-			*/
-
 		}
 	}
 
@@ -568,7 +727,7 @@ static qse_rex_node_t* comp0 (comp_t* c, qse_rex_node_t* ge)
 
 	while (IS_SPE(c,QSE_T('|')))
 	{
-		if (getc(c) <= -1) 
+		if (getc_esc(c) <= -1) 
 		{
 			//freere (left);
 			return QSE_NULL;
@@ -614,7 +773,7 @@ qse_rex_node_t* qse_rex_comp (
 	c.start = QSE_NULL;
 
 	/* read the first character */
-	if (getc(&c) <= -1) return QSE_NULL;
+	if (getc_esc(&c) <= -1) return QSE_NULL;
 
 	c.start = newstartnode (&c);
 	if (c.start == QSE_NULL) return QSE_NULL;