diff --git a/qse/doc/page/awk-lang.md b/qse/doc/page/awk-lang.md
index 7db3f742..8e540f73 100644
--- a/qse/doc/page/awk-lang.md
+++ b/qse/doc/page/awk-lang.md
@@ -126,7 +126,7 @@ and represents the value of 0.
 
 A string is enclosed in a pair of double quotes or single quotes.
 
-A character in a string encosed in the double-quotes, when preceded with 
+A character in a string enclosed in the double-quotes, when preceded with 
 a back-slash, changes the meaning. 
 
  - \\a - alert
@@ -149,16 +149,25 @@ In the octal sequence, you can specify up to 3 octal digits after \\; In the
 hexadecimal sequence, you can specify as many hexadecimal digits as possible 
 after \\x.  
 
-If the number doesn't fit in the range that the default character type 
-can represent, the character generated from the sequence is undefined.
+~~~~~{.awk}
+ BEGIN { 
+   print "\xC720\xB2C8\xCF54\xB4DC \x7D71\x4E00\x78BC"; 
+ }
+~~~~~
 
-You can use \\u and \\U in a string to specify a character by a Unicode code 
-point if  [Character Type](@ref installation) chosen for building is the 
-wide character type.
+This program should print \em 유니코드 \em 統一碼 if the character type can 
+represent the numbers in the sequence. If the number doesn't fit in the range 
+that the current character type can represent, the character generated from 
+the sequence is undefined.
 
- - \\uXXXX - X is a hexadecimal digit.
- - \\UXXXXXXXX - X is a hexadecimal digit.
+The \\u and \\U sequences, unlike ths \\x sequence, limits the maximum number of
+hexadecimal digits. It is available if the [Character Type](@ref installation)
+chosen for building is the wide character type. 
 
+ - \\uXXXX - X is a hexadecimal digit. up to 4 digits
+ - \\UXXXXXXXX - X is a hexadecimal digit. up to 8 digits
+
+The program above can be rewritten like this.
 
 ~~~~~{.awk}
  BEGIN { 
@@ -166,16 +175,25 @@ wide character type.
  }
 ~~~~~
 
-This program should print 유니코드 統一碼.
+If \\x, \\u, \\U are not followed by a hexadecimal digit, *x*, *u*, *U* are
+produced respectively.
 
-There are no escaping sequences supported for a string enclosed in the single
+There are no special sequences supported for a string enclosed in the single
 quotes. For that reason, you can't specify the single quote itself within
-a single-quoted string.
+a single-quoted string. The following program prints *awk* in double quotes.
+
+~~~~~{.awk}
+ BEGIN { 
+   print '"awk"';
+ }
+~~~~~
 
 ### Regular Expressions ###
 
-A regular expression is enclosed in a pair of forward slashes.
+A regular expression is enclosed in a pair of forward slashes. The special
+sequences for a double-quoted string are all supported in a regular expression.
 
+TBD.
 
 ### Note ###
 
@@ -189,42 +207,9 @@ Let's take this as an example.
 Since 0x not followed by a digit is a valid token, and T is an identifier,
 it is the same expression as 0x concatenated with T (0x @@ T).
 
-An AWK program can be composed of the following elements shown below. 
-Each language element requires the option in the second column to be on. 
-
-<table>
-<tr><th>Element                    </th><th>Option             </th></tr>
-<tr><td>Comment                    </td><td>                   </td></tr>
-<tr><td>Global variable declaration</td><td>                   </td></tr>
-<tr><td>Pattern-action block       </td><td>#QSE_AWK_PABLOCK   </td></tr>
-<tr><td>User-defined function      </td><td>                   </td></tr>
-<tr><td>\@include                  </td><td>#QSE_AWK_INCLUDE   </td></tr>
-</table>
-
-Single line comments begin with the '#' letter and end at the end of the
-same line. The C style multi-line comments are supported as well.
-Comments are ignored.
-
-- pattern-action-block := pattern action-block
-- pattern := BEGIN | END | expression | expression-range
-- expression-range := expression , expression
-
-A pattern in a pattern action block can be omitted.
-The action part can be omitted if the pattern is not BEGIN nor END.
-
-A pattern-action block, and a user-defined function can have the following elements.
-
-<table>
-<tr><th>Element                    </th><th>Option            </th></tr>
-<tr><td>Local variable declaration</td><td>                   </td></tr>
-<tr><td>Statement                 </td><td>                   </td></tr>
-<tr><td>getline                   </td><td>#QSE_AWK_RIO       </td></tr>
-<tr><td>print                     </td><td>#QSE_AWK_RIO       </td></tr>
-<tr><td>nextofile                 </td><td>#QSE_AWK_NEXTOFILE </td></tr>
-<tr><td>reset                     </td><td>#QSE_AWK_RESET     </td></tr>
-<tr><td>abort                     </td><td>#QSE_AWK_ABORT     </td></tr>
-</table>
 
+Commands
+--------
 
 AWK has the following statement constructs.
 - if
diff --git a/qse/lib/awk/parse.c b/qse/lib/awk/parse.c
index 214acf31..901d8fa8 100644
--- a/qse/lib/awk/parse.c
+++ b/qse/lib/awk/parse.c
@@ -3729,7 +3729,7 @@ static qse_awk_nde_t* parse_concat (qse_awk_t* awk, const qse_awk_loc_t* xloc)
 			   /* unary operators */
 			   MATCH(awk,TOK_PLUS) || MATCH(awk,TOK_MINUS) ||
 			   MATCH(awk,TOK_LNOT) || MATCH(awk,TOK_BNOT) || 
-			   MATCH(awk,TOK_COLON) ||
+			   MATCH(awk,TOK_BQUOTE) ||
 			   /* increment operators */
 			   MATCH(awk,TOK_PLUSPLUS) || MATCH(awk,TOK_MINUSMINUS) ||
 			   ((awk->opt.trait & QSE_AWK_TOLERANT) && 
diff --git a/qse/mod/awk/dir.c b/qse/mod/awk/dir.c
index 9fb16f65..37c47a61 100644
--- a/qse/mod/awk/dir.c
+++ b/qse/mod/awk/dir.c
@@ -281,7 +281,11 @@ static int read_byid (qse_awk_rtx_t* rtx, dir_list_t* list, qse_long_t id, qse_a
 		if (!tmp || qse_awk_rtx_setrefval (rtx, ref, tmp) <= -1) 
 		{
 			list->errnum = awk_err_to_errnum (qse_awk_rtx_geterrnum (rtx));
-			if (tmp) qse_awk_rtx_freeval (rtx, tmp);
+			if (tmp) 
+			{
+				qse_awk_rtx_refupval (rtx, tmp);
+				qse_awk_rtx_refdownval (rtx, tmp);
+			}
 			return -1;
 		}
 
diff --git a/qse/mod/awk/str.c b/qse/mod/awk/str.c
index ae7dcfc7..5a0246ff 100644
--- a/qse/mod/awk/str.c
+++ b/qse/mod/awk/str.c
@@ -22,6 +22,28 @@
 #include <qse/cmn/str.h>
 #include "../../lib/cmn/mem.h"
 
+static int fnc_normspc (qse_awk_rtx_t* rtx, const qse_awk_fnc_info_t* fi)
+{
+	/* normalize spaces 
+	 * - trim leading and trailing spaces
+	 * - replace a series of spaces to a single space
+	 */
+	qse_xstr_t path;
+	qse_awk_val_t* retv;
+
+	path.ptr = qse_awk_rtx_valtostrdup (
+		rtx, qse_awk_rtx_getarg(rtx, 0), &path.len);
+	if (path.ptr)
+	{
+		path.len = qse_strxpac (path.ptr, path.len);
+		retv = qse_awk_rtx_makestrval (rtx, path.ptr, path.len);
+		qse_awk_rtx_freemem (rtx, path.ptr);
+		if (retv) qse_awk_rtx_setretval (rtx, retv);
+	}
+
+	return 0;
+}
+
 static int trim (qse_awk_rtx_t* rtx, int flags)
 {
 	qse_xstr_t path;
@@ -33,12 +55,9 @@ static int trim (qse_awk_rtx_t* rtx, int flags)
 	if (path.ptr)
 	{
 		npath = qse_strxtrmx (path.ptr, &path.len, flags);
-
 		retv = qse_awk_rtx_makestrval (rtx, npath, path.len);
 		qse_awk_rtx_freemem (rtx, path.ptr);
-		if (retv == QSE_NULL) return -1;
-			
-		qse_awk_rtx_setretval (rtx, retv);
+		if (retv) qse_awk_rtx_setretval (rtx, retv);
 	}
 
 	return 0;
@@ -68,6 +87,7 @@ static fnctab_t fnctab[] =
 {
 	/* keep this table sorted for binary search in query(). */
 	{ QSE_T("ltrim"),    { { 1, 1, QSE_NULL }, fnc_ltrim,    0  } },
+	{ QSE_T("normspc"),  { { 1, 1, QSE_NULL }, fnc_normspc,  0  } },
 	{ QSE_T("rtrim"),    { { 1, 1, QSE_NULL }, fnc_rtrim,    0  } },
 	{ QSE_T("trim"),     { { 1, 1, QSE_NULL }, fnc_trim,     0  } }
 };
diff --git a/qse/mod/awk/sys.c b/qse/mod/awk/sys.c
index 7bfdb1f7..8d4b9729 100644
--- a/qse/mod/awk/sys.c
+++ b/qse/mod/awk/sys.c
@@ -568,7 +568,10 @@ static int fnc_getnwifcfg (qse_awk_rtx_t* rtx, const qse_awk_fnc_info_t* fi)
 				if (tmp)
 				{
 					if (qse_awk_rtx_setrefval (rtx, qse_awk_rtx_getarg (rtx, 2), tmp) <= -1)
-						qse_awk_rtx_freeval (rtx, tmp);
+					{
+						qse_awk_rtx_refupval (rtx, tmp);
+						qse_awk_rtx_refdownval (rtx, tmp);
+					}
 					else ret = 0;
 				}
 			}
diff --git a/qse/mod/awk/uci.c b/qse/mod/awk/uci.c
index f00017e6..49b1284a 100644
--- a/qse/mod/awk/uci.c
+++ b/qse/mod/awk/uci.c
@@ -473,7 +473,8 @@ static int getsection_byid (
 					{
 						if (qse_awk_rtx_setrefval (rtx, ref, tmp) <= -1)
 						{
-							qse_awk_rtx_freeval (rtx, tmp);
+							qse_awk_rtx_refupval (rtx, tmp);
+							qse_awk_rtx_refdownval (rtx, tmp);
 							x = UCI_ERR_MEM;
 						}
 					}
@@ -535,7 +536,8 @@ static int getoption_byid (
 						{
 							if (qse_awk_rtx_setrefval (rtx, ref, map) <= -1)
 							{
-								qse_awk_rtx_freeval (rtx, map);
+								qse_awk_rtx_refupval (rtx, map);
+								qse_awk_rtx_refdownval (rtx, map);
 								map = QSE_NULL;
 								x = UCI_ERR_MEM;
 							}
@@ -579,7 +581,8 @@ static int getoption_byid (
 								fld = qse_awk_rtx_makestrvalwithmbs (rtx, tmp->name);
 								if (!fld)
 								{
-									qse_awk_rtx_freeval (rtx, map);
+									qse_awk_rtx_refupval (rtx, map);
+									qse_awk_rtx_refdownval (rtx, map);
 									map = QSE_NULL;
 									x = UCI_ERR_MEM;
 									break;
@@ -600,8 +603,10 @@ static int getoption_byid (
 								if (kp == QSE_NULL || qse_awk_rtx_setmapvalfld (rtx, map, kp, kl, fld) == QSE_NULL)
 								{
 									if (kp) QSE_MMGR_FREE (qse_awk_rtx_getmmgr(rtx), kp);
-									qse_awk_rtx_freeval (rtx, fld);
-									qse_awk_rtx_freeval (rtx, map);
+									qse_awk_rtx_refupval (rtx, fld);
+									qse_awk_rtx_refdownval (rtx, fld);
+									qse_awk_rtx_refupval (rtx, map);
+									qse_awk_rtx_refdownval (rtx, map);
 									map = QSE_NULL;
 									x = UCI_ERR_MEM;
 									break;
@@ -615,7 +620,8 @@ static int getoption_byid (
 							{
 								if (qse_awk_rtx_setrefval (rtx, ref, map) <= -1)
 								{
-									qse_awk_rtx_freeval (rtx, map);
+									qse_awk_rtx_refupval (rtx, map);
+									qse_awk_rtx_refdownval (rtx, map);
 									map = QSE_NULL;
 									x = UCI_ERR_MEM;
 								}