diff --git a/qse/cmd/awk/awk.c b/qse/cmd/awk/awk.c
index cc365bfb..aca61593 100644
--- a/qse/cmd/awk/awk.c
+++ b/qse/cmd/awk/awk.c
@@ -382,23 +382,19 @@ struct opttab_t
 {
 	{ QSE_T("implicit"),     QSE_AWK_IMPLICIT,       QSE_T("allow undeclared variables") },
 	{ QSE_T("explicit"),     QSE_AWK_EXPLICIT,       QSE_T("allow declared variables(local,global)") },
-	{ QSE_T("extraops"),     QSE_AWK_EXTRAOPS,       QSE_T("enable extra operators(<<,>>,^^,\\)") },
+	{ QSE_T("extrakws"),     QSE_AWK_EXTRAKWS,       QSE_T("enable abort,reset,nextofile,OFILENAME,@include") },
 	{ QSE_T("rio"),          QSE_AWK_RIO,            QSE_T("enable builtin I/O including getline & print") },
 	{ QSE_T("rwpipe"),       QSE_AWK_RWPIPE,         QSE_T("allow a dual-directional pipe") },
 	{ QSE_T("newline"),      QSE_AWK_NEWLINE,        QSE_T("enable a newline to terminate a statement") },
 	{ QSE_T("striprecspc"),  QSE_AWK_STRIPRECSPC,    QSE_T("strip spaces in splitting a record") },
 	{ QSE_T("stripstrspc"),  QSE_AWK_STRIPSTRSPC,    QSE_T("strip spaces in string-to-number conversion") },
-	{ QSE_T("nextofile"),    QSE_AWK_NEXTOFILE,      QSE_T("enable 'nextofile'") },
-	{ QSE_T("reset"),        QSE_AWK_RESET,          QSE_T("enable 'reset'") },
 	{ QSE_T("crlf"),         QSE_AWK_CRLF,           QSE_T("use CRLF for a newline") },
 	{ QSE_T("maptovar"),     QSE_AWK_MAPTOVAR,       QSE_T("allow a map to be assigned or returned") },
 	{ QSE_T("pablock"),      QSE_AWK_PABLOCK,        QSE_T("enable pattern-action loop") },
 	{ QSE_T("rexbound"),     QSE_AWK_REXBOUND,       QSE_T("enable {n,m} in a regular expression") },
 	{ QSE_T("ncmponstr"),    QSE_AWK_NCMPONSTR,      QSE_T("perform numeric comparsion on numeric strings") },
 	{ QSE_T("strictnaming"), QSE_AWK_STRICTNAMING,   QSE_T("enable the strict naming rule") },
-	{ QSE_T("include"),      QSE_AWK_INCLUDE,        QSE_T("enable '@include'") },
 	{ QSE_T("tolerant"),     QSE_AWK_TOLERANT,       QSE_T("make more fault-tolerant") },
-	{ QSE_T("abort"),        QSE_AWK_ABORT,          QSE_T("enable 'abort'") },
 	{ QSE_NULL,              0,                      QSE_NULL }
 };
 
@@ -525,23 +521,19 @@ static int comparg (int argc, qse_char_t* argv[], struct arg_t* arg)
 	{
 		{ QSE_T(":implicit"),        QSE_T('\0') },
 		{ QSE_T(":explicit"),        QSE_T('\0') },
-		{ QSE_T(":extraops"),        QSE_T('\0') },
+		{ QSE_T(":extrakws"),        QSE_T('\0') },
 		{ QSE_T(":rio"),             QSE_T('\0') },
 		{ QSE_T(":rwpipe"),          QSE_T('\0') },
 		{ QSE_T(":newline"),         QSE_T('\0') },
 		{ QSE_T(":striprecspc"),     QSE_T('\0') },
 		{ QSE_T(":stripstrspc"),     QSE_T('\0') },
-		{ QSE_T(":nextofile"),       QSE_T('\0') },
-		{ QSE_T(":reset"),           QSE_T('\0') },
 		{ QSE_T(":crlf"),            QSE_T('\0') },
 		{ QSE_T(":maptovar"),        QSE_T('\0') },
 		{ QSE_T(":pablock"),         QSE_T('\0') },
 		{ QSE_T(":rexbound"),        QSE_T('\0') },
 		{ QSE_T(":ncmponstr"),       QSE_T('\0') },
 		{ QSE_T(":strictnaming"),    QSE_T('\0') },
-		{ QSE_T(":include"),         QSE_T('\0') },
 		{ QSE_T(":tolerant"),        QSE_T('\0') },
-		{ QSE_T(":abort"),           QSE_T('\0') },
 
 		{ QSE_T(":call"),            QSE_T('c') },
 		{ QSE_T(":file"),            QSE_T('f') },
diff --git a/qse/doc/page/awk.doc b/qse/doc/page/awk.doc
index d11624cf..f13a2b35 100644
--- a/qse/doc/page/awk.doc
+++ b/qse/doc/page/awk.doc
@@ -3,7 +3,8 @@
 @section awk_content CONTENTS
 - @ref awk_intro "INTRODUCTION"
 - @ref awk_lang "AWK LANGUAGE"
-- @ref awk_ext "AWK LANGUAGE EXTENSIONS"
+ - @ref awk_litvar        "LITERAL AND VARIABLE"
+ - @ref awk_ext_teq       "TEQ OPERATOR"
  - @ref awk_ext_vardecl   "VARIABLE DECLARATION"
  - @ref awk_ext_include   "INCLUDE"
  - @ref awk_ext_print     "EXTENDED PRINT/PRINTF"
@@ -255,9 +256,74 @@ AWK has the following statement constructs.
 - printf
 - expression
 
-@section awk_ext AWK LANGUAGE EXTENSIONS
-Some language extensions are implemented and those can be enabled by setting 
-the corresponding options.
+@subsection awk_litvar LITERAL AND VARIABLE
+
+Value type
+- Scalar
+-- String
+-- Integer
+-- Floating-Pointer number
+- Hashed Map
+- Regular expression
+
+Scalar values are immutable while a hashed map value is mutable.
+A regular expression value is specially treated.
+
+A variable is tied to a value when it is assigned with a value.
+If the variable is tied to a map value, it can't be assigned again.
+You can use 'reset' to untie the variable from the value, and thus
+restore the variable to the 'nil' state.
+
+....
+
+@subsection awk_ext_teq TEQ OPERATOR
+
+The === operator compares two values and evaluates to a non-zero value 
+if both have the same internal type and the actual values are the same.
+so 1 is not equal to 1.0 for the === operator.
+
+A map comparison for the === operator is a bit special. The contents of
+the map is never inspected. Comparing two maps always result in inequality.
+
+However, if two variables points to the same map value, it can evaluate
+to a non-zero value. This is possible if you allow assigning a map to 
+another non-map variable with #QSE_AWK_MAPTOVAR. In this case, a map
+is not deep-copied but the reference to it is copied.
+
+@code
+BEGIN { 
+	a[10]=20; 
+	b=a; 
+	b[20]=40;
+	for (i in a) print i, a[i];  
+	print a===b;
+}
+@endcode
+
+
+The === operator may be also useful when you want to indicate an error
+with an uninitialized variable. The following code check if the function
+returned a map. Since the variable 'nil' has never been assigned, its 
+internal type is 'NIL' and 
+
+@code
+function a ()
+{
+	x[10] = 2;
+	return x;
+}
+
+BEGIN {
+	t = a();
+	if (t === nil)
+		print "nil";
+	else
+		print "ok";
+}
+@endcode.
+
+The !== operator is a negated form of the === operator.
+
 
 @subsection awk_ext_vardecl VARIABLE DECLARATION
 
@@ -303,6 +369,16 @@ blocks appear. To use \@include, you must turn on #QSE_AWK_INCLUDE.
 BEGIN { func_in_abc (); }
 @endcode
 
+A semicolon is optional after the included file name. The following is the 
+same as the sample above.
+@code
+@include "abc.awk";
+BEGIN { func_in_abc(); }
+@endcode
+
+If #QSE_AWK_NEWLINE is off, the semicolon is required.
+
+
 @subsection awk_ext_print EXTENDED PRINT/PRINTF
 When #QSE_AWK_TOLERANT is on, print and printf are treated as if
 they are function calls.  In this mode, they return a negative number
diff --git a/qse/include/qse/awk/awk.h b/qse/include/qse/awk/awk.h
index 46b78ca5..d4f09147 100644
--- a/qse/include/qse/awk/awk.h
+++ b/qse/include/qse/awk/awk.h
@@ -460,6 +460,7 @@ struct qse_awk_sio_lxc_t
 };
 typedef struct qse_awk_sio_lxc_t qse_awk_sio_lxc_t;
 
+typedef struct qse_awk_sio_arg_t qse_awk_sio_arg_t;
 struct qse_awk_sio_arg_t 
 {
 	const qse_char_t* name;   /**< [IN] name of I/O object */
@@ -477,9 +478,8 @@ struct qse_awk_sio_arg_t
 	qse_size_t colm;
 
 	qse_awk_sio_lxc_t last;
-	struct qse_awk_sio_arg_t* next;
+	qse_awk_sio_arg_t* next;
 };
-typedef struct qse_awk_sio_arg_t qse_awk_sio_arg_t;
 
 /**
  * The qse_awk_sio_impl_t type defines a source IO function
@@ -892,23 +892,18 @@ enum qse_awk_trait_t
 	/**
 	 * allows undeclared variables and implicit concatenation 
 	 **/
-	QSE_AWK_IMPLICIT    = (1 << 0),
+	QSE_AWK_IMPLICIT = (1 << 0),
 
 	/** 
 	 * allows explicit variable declaration, the concatenation
 	 * operator, a period, and performs the parse-time function check. 
 	 */
-	QSE_AWK_EXPLICIT    = (1 << 1), 
+	QSE_AWK_EXPLICIT = (1 << 1), 
 
-	/** 
-	 * supports extra operators:
-	 * - @b <<, <<= left-shift
-	 * - @b >>, >>= right-shiftt
-	 * - @b ^^, ^^= xor
-	 * - @b ~  bitwise-not
-	 * - @b // idiv (get quotient)
+	/**
+	 * enable abort,reset,nextofile,OFILENAME,@include.
 	 */
-	QSE_AWK_EXTRAOPS = (1 << 2), 
+	QSE_AWK_EXTRAKWS = (1 << 2),
 
 	/** supports @b getline and @b print */
 	QSE_AWK_RIO = (1 << 3), 
@@ -951,12 +946,6 @@ enum qse_awk_trait_t
 	 */
 	QSE_AWK_STRIPSTRSPC = (1 << 7),
 
-	/** enables @b nextofile */
-	QSE_AWK_NEXTOFILE = (1 << 8),
-
-	/** enables @b reset */
-	QSE_AWK_RESET = (1 << 9),
-
 	/** CR + LF by default */
 	QSE_AWK_CRLF = (1 << 10),
 
@@ -1005,9 +994,6 @@ enum qse_awk_trait_t
 	 */
 	QSE_AWK_TOLERANT = (1 << 17),
 
-	/** enables @b abort */
-	QSE_AWK_ABORT = (1 << 18),
-
 	/** 
 	 * makes #qse_awk_t to behave compatibly with classical AWK
 	 * implementations
@@ -1112,18 +1098,18 @@ enum qse_awk_errnum_t
 	QSE_AWK_EARGTF,        /**< too few arguments */
 	QSE_AWK_EARGTM,        /**< too many arguments */
 	QSE_AWK_EFUNNF,        /**< function '${0}' not found */
-	QSE_AWK_ENOTIDX,       /**< variable not indexable */
-	QSE_AWK_ENOTDEL,       /**< variable '${0}' not deletable */
+	QSE_AWK_ENOTIDX,       /**< not indexable */
+	QSE_AWK_ENOTDEL,       /**< '${0}' not deletable */
 	QSE_AWK_ENOTMAP,       /**< value not a map */
 	QSE_AWK_ENOTMAPIN,     /**< right-hand side of 'in' not a map */
 	QSE_AWK_ENOTMAPNILIN,  /**< right-hand side of 'in' not a map nor nil */
 	QSE_AWK_ENOTREF,       /**< value not referenceable */
 	QSE_AWK_ENOTASS,       /**< value not assignable */
-	QSE_AWK_EIDXVALASSMAP, /**< an indexed value cannot be assigned a map */
-	QSE_AWK_EPOSVALASSMAP, /**< a positional cannot be assigned a map */
-	QSE_AWK_EMAPTOSCALAR,  /**< map '${0}' not assignable with a scalar */
+	QSE_AWK_EIDXVALASSMAP, /**< indexed value cannot be assigned a map */
+	QSE_AWK_EPOSVALASSMAP, /**< positional cannot be assigned a map */
+	QSE_AWK_EMAPNA,        /**< map '${0}' not assignable */
+	QSE_AWK_EMAPPH,        /**< map prohibited */
 	QSE_AWK_ESCALARTOMAP,  /**< cannot change a scalar value to a map */
-	QSE_AWK_EMAPNA,        /**< map not allowed */
 	QSE_AWK_EVALTYPE,      /**< invalid value type */
 	QSE_AWK_ERNEXTBEG,     /**< 'next' called from BEGIN block */
 	QSE_AWK_ERNEXTEND,     /**< 'next' called from END block */
diff --git a/qse/lib/awk/err.c b/qse/lib/awk/err.c
index 2e8cf8c3..19ab6b50 100644
--- a/qse/lib/awk/err.c
+++ b/qse/lib/awk/err.c
@@ -109,8 +109,8 @@ const qse_char_t* qse_awk_dflerrstr (const qse_awk_t* awk, qse_awk_errnum_t errn
 		QSE_T("too few arguments"),
 		QSE_T("too many arguments"),
 		QSE_T("function '${0}' not found"),
-		QSE_T("variable not indexable"),
-		QSE_T("variable '${0}' not deletable"),
+		QSE_T("not indexable"),
+		QSE_T("'${0}' not deletable"),
 		QSE_T("value not a map"),
 		QSE_T("right-hand side of the 'in' operator not a map"),
 		QSE_T("right-hand side of the 'in' operator not a map nor nil"),
@@ -118,9 +118,9 @@ const qse_char_t* qse_awk_dflerrstr (const qse_awk_t* awk, qse_awk_errnum_t errn
 		QSE_T("value not assignable"),
 		QSE_T("indexed value cannot be assigned a map"),
 		QSE_T("positional value cannot be assigned a map"),
-		QSE_T("map '${0}' not assignable with a scalar"),
+		QSE_T("map '${0}' not assignable"),
+		QSE_T("map prohibited"),
 		QSE_T("cannot change a scalar value to a map"),
-		QSE_T("map not allowed"),
 		QSE_T("invalid value type"),
 		QSE_T("'next' called from BEGIN block"),
 		QSE_T("'next' called from END block"),
diff --git a/qse/lib/awk/fnc.c b/qse/lib/awk/fnc.c
index 627a889a..1ce4a0ba 100644
--- a/qse/lib/awk/fnc.c
+++ b/qse/lib/awk/fnc.c
@@ -652,9 +652,12 @@ static int fnc_split (qse_awk_rtx_t* run, const qse_awk_fnc_info_t* fi)
 	if ((*a1_ref)->type != QSE_AWK_VAL_NIL &&
 	    (*a1_ref)->type != QSE_AWK_VAL_MAP)
 	{
-		/* cannot change a scalar value to a map */
-		qse_awk_rtx_seterrnum (run, QSE_AWK_ESCALARTOMAP, QSE_NULL);
-		return -1;
+		if (!(run->awk->opt.trait & QSE_AWK_MAPTOVAR))
+		{
+			/* cannot change a scalar value to a map */
+			qse_awk_rtx_seterrnum (run, QSE_AWK_ESCALARTOMAP, QSE_NULL);
+			return -1;
+		}
 	}
 
 	if (a0->type == QSE_AWK_VAL_STR)
@@ -976,7 +979,7 @@ static int __substitute (qse_awk_rtx_t* run, qse_long_t max_count)
 		if ((*a2_ref)->type == QSE_AWK_VAL_MAP)
 		{
 			/* a map is not allowed as the third parameter */
-			qse_awk_rtx_seterrnum (run, QSE_AWK_EMAPNA, QSE_NULL);
+			qse_awk_rtx_seterrnum (run, QSE_AWK_EMAPPH, QSE_NULL);
 			goto oops;
 		}
 
diff --git a/qse/lib/awk/parse.c b/qse/lib/awk/parse.c
index d109b7c4..51688c61 100644
--- a/qse/lib/awk/parse.c
+++ b/qse/lib/awk/parse.c
@@ -28,8 +28,8 @@ enum tok_t
 	/* special token to direct the parser to include a file specified */
 	TOK_INCLUDE,
 
-	/* TOK_XXX_ASSNs should be in sync
-	 * with assop in assign_to_opcode */
+	/* TOK_XXX_ASSNs should be in sync with assop in assign_to_opcode. 
+	 * it also should be in the order as qse_awk_assop_type_t in run.h */
 	TOK_ASSN,
 	TOK_PLUS_ASSN,
 	TOK_MINUS_ASSN,
@@ -46,12 +46,15 @@ enum tok_t
 	TOK_BOR_ASSN,
 	/* end of TOK_XXX_ASSN */
 
+	TOK_TEQ,
+	TOK_TNE,
 	TOK_EQ,
 	TOK_NE,
 	TOK_LE,
 	TOK_LT,
 	TOK_GE,
 	TOK_GT,
+	TOK_MA,   /* match */
 	TOK_NM,   /* not match */
 	TOK_LNOT, /* logical negation ! */
 	TOK_PLUS,
@@ -67,7 +70,7 @@ enum tok_t
 	TOK_BOR,
 	TOK_BXOR,
 	TOK_BAND,
-	TOK_TILDE, /* used for unary bitwise-not and regex match */
+	TOK_BNOT, /* used for unary bitwise-not and regex match */
 	TOK_RS,
 	TOK_LS,
 	TOK_IN,
@@ -259,7 +262,7 @@ static kwent_t kwtab[] =
 	 * also keep it sorted by the first field for binary search */
 	{ { QSE_T("BEGIN"),        5 }, TOK_BEGIN,       QSE_AWK_PABLOCK },
 	{ { QSE_T("END"),          3 }, TOK_END,         QSE_AWK_PABLOCK },
-	{ { QSE_T("abort"),        5 }, TOK_ABORT,       QSE_AWK_ABORT },
+	{ { QSE_T("abort"),        5 }, TOK_ABORT,       QSE_AWK_EXTRAKWS },
 	{ { QSE_T("break"),        5 }, TOK_BREAK,       0 },
 	{ { QSE_T("continue"),     8 }, TOK_CONTINUE,    0 },
 	{ { QSE_T("delete"),       6 }, TOK_DELETE,      0 },
@@ -272,14 +275,14 @@ static kwent_t kwtab[] =
 	{ { QSE_T("global"),       6 }, TOK_GLOBAL,      QSE_AWK_EXPLICIT },
 	{ { QSE_T("if"),           2 }, TOK_IF,          0 },
 	{ { QSE_T("in"),           2 }, TOK_IN,          0 },
-	{ { QSE_T("include"),      7 }, TOK_INCLUDE,     QSE_AWK_INCLUDE },
+	{ { QSE_T("include"),      7 }, TOK_INCLUDE,     QSE_AWK_EXTRAKWS },
 	{ { QSE_T("local"),        5 }, TOK_LOCAL,       QSE_AWK_EXPLICIT },
 	{ { QSE_T("next"),         4 }, TOK_NEXT,        QSE_AWK_PABLOCK },
 	{ { QSE_T("nextfile"),     8 }, TOK_NEXTFILE,    QSE_AWK_PABLOCK },
-	{ { QSE_T("nextofile"),    9 }, TOK_NEXTOFILE,   QSE_AWK_PABLOCK | QSE_AWK_NEXTOFILE },
+	{ { QSE_T("nextofile"),    9 }, TOK_NEXTOFILE,   QSE_AWK_PABLOCK | QSE_AWK_EXTRAKWS },
 	{ { QSE_T("print"),        5 }, TOK_PRINT,       QSE_AWK_RIO },
 	{ { QSE_T("printf"),       6 }, TOK_PRINTF,      QSE_AWK_RIO },
-	{ { QSE_T("reset"),        5 }, TOK_RESET,       QSE_AWK_RESET },
+	{ { QSE_T("reset"),        5 }, TOK_RESET,       QSE_AWK_EXTRAKWS },
 	{ { QSE_T("return"),       6 }, TOK_RETURN,      0 },
 	{ { QSE_T("while"),        5 }, TOK_WHILE,       0 }
 };
@@ -319,7 +322,7 @@ static global_t gtab[] =
 	{ QSE_T("NR"),           2,  QSE_AWK_PABLOCK },
 
 	/* current output file name */
-	{ QSE_T("OFILENAME"),    9,  QSE_AWK_PABLOCK | QSE_AWK_NEXTOFILE },
+	{ QSE_T("OFILENAME"),    9,  QSE_AWK_PABLOCK | QSE_AWK_EXTRAKWS },
 
 	/* output real-to-str conversion format for 'print' */
 	{ QSE_T("OFMT"),         4,  QSE_AWK_RIO }, 
@@ -385,12 +388,7 @@ static global_t gtab[] =
 	qse_awk_seterror (awk, QSE_AWK_ENOERR, QSE_NULL, QSE_NULL)
 
 #define SETERR_TOK(awk,code) \
-	do { \
-		qse_cstr_t __ea; \
-		__ea.len = QSE_STR_LEN((awk)->tok.name); \
-		__ea.ptr = QSE_STR_PTR((awk)->tok.name); \
-		qse_awk_seterror (awk, code, &__ea, &(awk)->tok.loc); \
-	} while (0)
+	qse_awk_seterror (awk, code, QSE_STR_CSTR((awk)->tok.name), &(awk)->tok.loc)
 
 #define SETERR_COD(awk,code) \
 	qse_awk_seterror (awk, code, QSE_NULL, QSE_NULL)
@@ -673,6 +671,46 @@ int qse_awk_parse (qse_awk_t* awk, qse_awk_sio_t* sio)
 	return n;
 }
 
+static int end_include (qse_awk_t* awk)
+{
+	int x;
+	qse_awk_sio_arg_t* cur;
+
+	if (awk->sio.inp == &awk->sio.arg) return 0; /* no include */
+
+	/* if it is an included file, close it and
+	 * retry to read a character from an outer file */
+
+	CLRERR (awk);
+	x = awk->sio.inf (
+		awk, QSE_AWK_SIO_CLOSE, 
+		awk->sio.inp, QSE_NULL, 0);
+
+	/* if closing has failed, still destroy the
+	 * sio structure first as normal and return
+	 * the failure below. this way, the caller 
+	 * does not call QSE_AWK_SIO_CLOSE on 
+	 * awk->sio.inp again. */
+
+	cur = awk->sio.inp;
+	awk->sio.inp = awk->sio.inp->next;
+
+	QSE_ASSERT (cur->name != QSE_NULL);
+	QSE_MMGR_FREE (awk->mmgr, cur);
+	awk->parse.depth.incl--;
+
+	if (x != 0)
+	{
+		/* the failure mentioned above is returned here */
+		if (ISNOERR(awk))
+			SETERR_ARG (awk, QSE_AWK_ECLOSE, QSE_T("<SIN>"), 5);
+		return -1;
+	}
+
+	awk->sio.last = awk->sio.inp->last;
+	return 1; /* ended the included file successfully */
+}
+
 static int begin_include (qse_awk_t* awk)
 {
 	qse_ssize_t op;
@@ -747,50 +785,21 @@ static int begin_include (qse_awk_t* awk)
 	awk->sio.inp->line = 1;
 	awk->sio.inp->colm = 1;
 
-	return 0;
-
-oops:
-	if (arg != QSE_NULL) QSE_MMGR_FREE (awk->mmgr, arg);
-	return -1;
-}
-
-static int end_include (qse_awk_t* awk)
-{
-	int x;
-	qse_awk_sio_arg_t* cur;
-
-	if (awk->sio.inp == &awk->sio.arg) return 0; /* no include */
-
-	/* if it is an included file, close it and
-	 * retry to read a character from an outer file */
-
-	CLRERR (awk);
-	x = awk->sio.inf (
-		awk, QSE_AWK_SIO_CLOSE, 
-		awk->sio.inp, QSE_NULL, 0);
-
-	/* if closing has failed, still destroy the
-	 * sio structure first as normal and return
-	 * the failure below. this way, the caller 
-	 * does not call QSE_AWK_SIO_CLOSE on 
-	 * awk->sio.inp again. */
-
-	cur = awk->sio.inp;
-	awk->sio.inp = awk->sio.inp->next;
-
-	QSE_ASSERT (cur->name != QSE_NULL);
-	QSE_MMGR_FREE (awk->mmgr, cur);
-	awk->parse.depth.incl--;
-
-	if (x != 0)
+	/* read in the first character in the included file. 
+	 * so the next call to get_token() sees the character read
+	 * from this file. */
+	if (get_char (awk) <= -1) 
 	{
-		/* the failure mentioned above is returned here */
-		if (ISNOERR(awk))
-			SETERR_ARG (awk, QSE_AWK_ECLOSE, QSE_T("<SIN>"), 5);
+		end_include (awk); 
+		/* since i've called end_include(), i don't go to oops */
 		return -1;
 	}
 
-	return 1; /* ended the included file successfully */
+	return 0;
+
+oops:
+	if (arg) QSE_MMGR_FREE (awk->mmgr, arg);
+	return -1;
 }
 
 static qse_awk_t* parse_progunit (qse_awk_t* awk)
@@ -849,9 +858,10 @@ retry:
 			}
 
 			if (begin_include (awk) <= -1) return QSE_NULL;
-			
-			/* read the first meaningful token from the included file 
-			 * and recheck it by jumping to retry: */
+
+			/* i'm retrying to get the first top-level
+			 * element as if parse_progunit() is called. 
+			 * so i need to skip NEWLINE tokens */
 			do
 			{
 				if (get_token(awk) <= -1) return QSE_NULL; 
@@ -898,6 +908,10 @@ retry:
 
 		awk->parse.id.block = PARSE_BEGIN_BLOCK;
 		if (parse_begin (awk) == QSE_NULL) return QSE_NULL;
+
+		/* skip a semicolon after an action block if any */
+		if (MATCH(awk,TOK_SEMICOLON) && 
+		    get_token (awk) <= -1) return QSE_NULL;
 	}
 	else if (MATCH(awk,TOK_END)) 
 	{
@@ -926,6 +940,10 @@ retry:
 
 		awk->parse.id.block = PARSE_END_BLOCK;
 		if (parse_end (awk) == QSE_NULL) return QSE_NULL;
+
+		/* skip a semicolon after an action block if any */
+		if (MATCH(awk,TOK_SEMICOLON) && 
+		    get_token (awk) <= -1) return QSE_NULL;
 	}
 	else if (MATCH(awk,TOK_LBRACE))
 	{
@@ -3629,8 +3647,7 @@ oops:
 	return QSE_NULL;
 }
 
-static qse_awk_nde_t* parse_logical_or (
-	qse_awk_t* awk, const qse_awk_loc_t* xloc)
+static qse_awk_nde_t* parse_logical_or (qse_awk_t* awk, const qse_awk_loc_t* xloc)
 {
 	static binmap_t map[] = 
 	{
@@ -3641,8 +3658,7 @@ static qse_awk_nde_t* parse_logical_or (
 	return parse_binary (awk, xloc, 1, map, parse_logical_and);
 }
 
-static qse_awk_nde_t* parse_logical_and (
-	qse_awk_t* awk, const qse_awk_loc_t* xloc)
+static qse_awk_nde_t* parse_logical_and (qse_awk_t* awk, const qse_awk_loc_t* xloc)
 {
 	static binmap_t map[] = 
 	{
@@ -3653,8 +3669,7 @@ static qse_awk_nde_t* parse_logical_and (
 	return parse_binary (awk, xloc, 1, map, parse_in);
 }
 
-static qse_awk_nde_t* parse_in (
-	qse_awk_t* awk, const qse_awk_loc_t* xloc)
+static qse_awk_nde_t* parse_in (qse_awk_t* awk, const qse_awk_loc_t* xloc)
 {
 	/* 
 	static binmap_t map[] =
@@ -3708,21 +3723,19 @@ oops:
 	return QSE_NULL;
 }
 
-static qse_awk_nde_t* parse_regex_match (
-	qse_awk_t* awk, const qse_awk_loc_t* xloc)
+static qse_awk_nde_t* parse_regex_match (qse_awk_t* awk, const qse_awk_loc_t* xloc)
 {
 	static binmap_t map[] =
 	{
-		{ TOK_TILDE, QSE_AWK_BINOP_MA },
-		{ TOK_NM,    QSE_AWK_BINOP_NM },
-		{ TOK_EOF,   0 },
+		{ TOK_MA,  QSE_AWK_BINOP_MA },
+		{ TOK_NM,  QSE_AWK_BINOP_NM },
+		{ TOK_EOF, 0 },
 	};
 
 	return parse_binary (awk, xloc, 0, map, parse_bitwise_or);
 }
 
-static qse_awk_nde_t* parse_bitwise_or (
-	qse_awk_t* awk, const qse_awk_loc_t* xloc)
+static qse_awk_nde_t* parse_bitwise_or (qse_awk_t* awk, const qse_awk_loc_t* xloc)
 {
 	static binmap_t map[] = 
 	{
@@ -3733,8 +3746,7 @@ static qse_awk_nde_t* parse_bitwise_or (
 	return parse_binary (awk, xloc, 0, map, parse_bitwise_xor);
 }
 
-static qse_awk_nde_t* parse_bitwise_xor (
-	qse_awk_t* awk, const qse_awk_loc_t* xloc)
+static qse_awk_nde_t* parse_bitwise_xor (qse_awk_t* awk, const qse_awk_loc_t* xloc)
 {
 	static binmap_t map[] = 
 	{
@@ -3745,8 +3757,7 @@ static qse_awk_nde_t* parse_bitwise_xor (
 	return parse_binary (awk, xloc, 0, map, parse_bitwise_and);
 }
 
-static qse_awk_nde_t* parse_bitwise_and (
-	qse_awk_t* awk, const qse_awk_loc_t* xloc)
+static qse_awk_nde_t* parse_bitwise_and (qse_awk_t* awk, const qse_awk_loc_t* xloc)
 {
 	static binmap_t map[] = 
 	{
@@ -3757,11 +3768,12 @@ static qse_awk_nde_t* parse_bitwise_and (
 	return parse_binary (awk, xloc, 0, map, parse_equality);
 }
 
-static qse_awk_nde_t* parse_equality (
-	qse_awk_t* awk, const qse_awk_loc_t* xloc)
+static qse_awk_nde_t* parse_equality (qse_awk_t* awk, const qse_awk_loc_t* xloc)
 {
 	static binmap_t map[] = 
 	{
+		{ TOK_TEQ, QSE_AWK_BINOP_TEQ },
+		{ TOK_TNE, QSE_AWK_BINOP_TNE },
 		{ TOK_EQ, QSE_AWK_BINOP_EQ },
 		{ TOK_NE, QSE_AWK_BINOP_NE },
 		{ TOK_EOF, 0 }
@@ -3770,8 +3782,7 @@ static qse_awk_nde_t* parse_equality (
 	return parse_binary (awk, xloc, 0, map, parse_relational);
 }
 
-static qse_awk_nde_t* parse_relational (
-	qse_awk_t* awk, const qse_awk_loc_t* xloc)
+static qse_awk_nde_t* parse_relational (qse_awk_t* awk, const qse_awk_loc_t* xloc)
 {
 	static binmap_t map[] = 
 	{
@@ -3782,12 +3793,10 @@ static qse_awk_nde_t* parse_relational (
 		{ TOK_EOF, 0 }
 	};
 
-	return parse_binary (awk, xloc, 0, map, 
-		((awk->opt.trait & QSE_AWK_EXTRAOPS)? parse_shift: parse_concat));
+	return parse_binary (awk, xloc, 0, map, parse_shift);
 }
 
-static qse_awk_nde_t* parse_shift (
-	qse_awk_t* awk, const qse_awk_loc_t* xloc)
+static qse_awk_nde_t* parse_shift (qse_awk_t* awk, const qse_awk_loc_t* xloc)
 {
 	static binmap_t map[] = 
 	{
@@ -3799,8 +3808,7 @@ static qse_awk_nde_t* parse_shift (
 	return parse_binary (awk, xloc, 0, map, parse_concat);
 }
 
-static qse_awk_nde_t* parse_concat (
-	qse_awk_t* awk, const qse_awk_loc_t* xloc)
+static qse_awk_nde_t* parse_concat (qse_awk_t* awk, const qse_awk_loc_t* xloc)
 {
 	qse_awk_nde_t* left = QSE_NULL; 
 	qse_awk_nde_t* right = QSE_NULL;
@@ -3853,8 +3861,7 @@ oops:
 	return QSE_NULL;
 }
 
-static qse_awk_nde_t* parse_additive (
-	qse_awk_t* awk, const qse_awk_loc_t* xloc)
+static qse_awk_nde_t* parse_additive (qse_awk_t* awk, const qse_awk_loc_t* xloc)
 {
 	static binmap_t map[] = 
 	{
@@ -3866,8 +3873,7 @@ static qse_awk_nde_t* parse_additive (
 	return parse_binary (awk, xloc, 0, map, parse_multiplicative);
 }
 
-static qse_awk_nde_t* parse_multiplicative (
-	qse_awk_t* awk, const qse_awk_loc_t* xloc)
+static qse_awk_nde_t* parse_multiplicative (qse_awk_t* awk, const qse_awk_loc_t* xloc)
 {
 	static binmap_t map[] = 
 	{
@@ -3882,8 +3888,7 @@ static qse_awk_nde_t* parse_multiplicative (
 	return parse_binary (awk, xloc, 0, map, parse_unary);
 }
 
-static qse_awk_nde_t* parse_unary (
-	qse_awk_t* awk, const qse_awk_loc_t* xloc)
+static qse_awk_nde_t* parse_unary (qse_awk_t* awk, const qse_awk_loc_t* xloc)
 {
 	qse_awk_nde_t* left;
 	qse_awk_loc_t uloc;
@@ -3894,8 +3899,7 @@ static qse_awk_nde_t* parse_unary (
 	opcode = (MATCH(awk,TOK_PLUS))?  QSE_AWK_UNROP_PLUS:
 	         (MATCH(awk,TOK_MINUS))? QSE_AWK_UNROP_MINUS:
 	         (MATCH(awk,TOK_LNOT))?  QSE_AWK_UNROP_LNOT:
-	         ((awk->opt.trait & QSE_AWK_EXTRAOPS) && MATCH(awk,TOK_TILDE))? 
-	                                   QSE_AWK_UNROP_BNOT: -1;
+	         (MATCH(awk,TOK_BNOT))?  QSE_AWK_UNROP_BNOT: -1;
 
 	/*if (opcode <= -1) return parse_increment (awk);*/
 	if (opcode <= -1) return parse_exponent (awk, xloc);
@@ -4023,8 +4027,7 @@ static qse_awk_nde_t* parse_unary (
 	}
 }
 
-static qse_awk_nde_t* parse_exponent (
-	qse_awk_t* awk, const qse_awk_loc_t* xloc)
+static qse_awk_nde_t* parse_exponent (qse_awk_t* awk, const qse_awk_loc_t* xloc)
 {
 	static binmap_t map[] = 
 	{
@@ -4035,8 +4038,7 @@ static qse_awk_nde_t* parse_exponent (
 	return parse_binary (awk, xloc, 0, map, parse_unary_exp);
 }
 
-static qse_awk_nde_t* parse_unary_exp (
-	qse_awk_t* awk, const qse_awk_loc_t* xloc)
+static qse_awk_nde_t* parse_unary_exp (qse_awk_t* awk, const qse_awk_loc_t* xloc)
 {
 	qse_awk_nde_exp_t* nde; 
 	qse_awk_nde_t* left;
@@ -4046,8 +4048,7 @@ static qse_awk_nde_t* parse_unary_exp (
 	opcode = (MATCH(awk,TOK_PLUS))?  QSE_AWK_UNROP_PLUS:
 	         (MATCH(awk,TOK_MINUS))? QSE_AWK_UNROP_MINUS:
 	         (MATCH(awk,TOK_LNOT))?  QSE_AWK_UNROP_LNOT:
-	         ((awk->opt.trait & QSE_AWK_EXTRAOPS) && MATCH(awk,TOK_TILDE))? 
-	                                   QSE_AWK_UNROP_BNOT: -1;
+	         (MATCH(awk,TOK_BNOT))?  QSE_AWK_UNROP_BNOT: -1;
 
 	if (opcode <= -1) return parse_increment (awk, xloc);
 
@@ -4085,8 +4086,7 @@ static qse_awk_nde_t* parse_unary_exp (
 	return (qse_awk_nde_t*)nde;
 }
 
-static qse_awk_nde_t* parse_increment (
-	qse_awk_t* awk, const qse_awk_loc_t* xloc)
+static qse_awk_nde_t* parse_increment (qse_awk_t* awk, const qse_awk_loc_t* xloc)
 {
 	qse_awk_nde_exp_t* nde;
 	qse_awk_nde_t* left;
@@ -5805,16 +5805,18 @@ static int get_symbols (qse_awk_t* awk, qse_cint_t c, qse_awk_tok_t* tok)
 
 	static struct ops_t ops[] = 
 	{
+		{ QSE_T("==="), 3, TOK_TEQ,          0 },
 		{ QSE_T("=="),  2, TOK_EQ,           0 },
 		{ QSE_T("="),   1, TOK_ASSN,         0 },
+		{ QSE_T("!=="), 3, TOK_TNE,          0 },
 		{ QSE_T("!="),  2, TOK_NE,           0 },
 		{ QSE_T("!~"),  2, TOK_NM,           0 },
 		{ QSE_T("!"),   1, TOK_LNOT,         0 },
-		{ QSE_T(">>="), 3, TOK_RS_ASSN,      QSE_AWK_EXTRAOPS },
+		{ QSE_T(">>="), 3, TOK_RS_ASSN,      0 },
 		{ QSE_T(">>"),  2, TOK_RS,           0 },
 		{ QSE_T(">="),  2, TOK_GE,           0 },
 		{ QSE_T(">"),   1, TOK_GT,           0 },
-		{ QSE_T("<<="), 3, TOK_LS_ASSN,      QSE_AWK_EXTRAOPS },
+		{ QSE_T("<<="), 3, TOK_LS_ASSN,      0 },
 		{ QSE_T("<<"),  2, TOK_LS,           0 },
 		{ QSE_T("<="),  2, TOK_LE,           0 },
 		{ QSE_T("<"),   1, TOK_LT,           0 },
@@ -5824,8 +5826,8 @@ static int get_symbols (qse_awk_t* awk, qse_cint_t c, qse_awk_tok_t* tok)
 		{ QSE_T("&&"),  2, TOK_LAND,         0 },
 		{ QSE_T("&="),  2, TOK_BAND_ASSN,    0 },
 		{ QSE_T("&"),   1, TOK_BAND,         0 },
-		{ QSE_T("^^="), 3, TOK_BXOR_ASSN,    QSE_AWK_EXTRAOPS },
-		{ QSE_T("^^"),  2, TOK_BXOR,         QSE_AWK_EXTRAOPS },
+		{ QSE_T("^^="), 3, TOK_BXOR_ASSN,    0 },
+		{ QSE_T("^^"),  2, TOK_BXOR,         0 },
 		{ QSE_T("^="),  2, TOK_EXP_ASSN,     0 },
 		{ QSE_T("^"),   1, TOK_EXP,          0 },
 		{ QSE_T("++"),  2, TOK_PLUSPLUS,     0 },
@@ -5834,19 +5836,20 @@ static int get_symbols (qse_awk_t* awk, qse_cint_t c, qse_awk_tok_t* tok)
 		{ QSE_T("--"),  2, TOK_MINUSMINUS,   0 },
 		{ QSE_T("-="),  2, TOK_MINUS_ASSN,   0 },
 		{ QSE_T("-"),   1, TOK_MINUS,        0 },
-		{ QSE_T("**="), 3, TOK_EXP_ASSN,     QSE_AWK_EXTRAOPS },
-		{ QSE_T("**"),  2, TOK_EXP,          QSE_AWK_EXTRAOPS },
+		{ QSE_T("**="), 3, TOK_EXP_ASSN,     0 },
+		{ QSE_T("**"),  2, TOK_EXP,          0 },
 		{ QSE_T("*="),  2, TOK_MUL_ASSN,     0 },
 		{ QSE_T("*"),   1, TOK_MUL,          0 },
 		{ QSE_T("/="),  2, TOK_DIV_ASSN,     0 },
 		{ QSE_T("/"),   1, TOK_DIV,          0 },
-		{ QSE_T("\\="), 2, TOK_IDIV_ASSN,    QSE_AWK_EXTRAOPS },
-		{ QSE_T("\\"),  1, TOK_IDIV,         QSE_AWK_EXTRAOPS },
-		{ QSE_T("%%="), 3, TOK_CONCAT_ASSN,  QSE_AWK_EXPLICIT },
-		{ QSE_T("%%"),  2, TOK_CONCAT,       QSE_AWK_EXPLICIT },
+		{ QSE_T("\\="), 2, TOK_IDIV_ASSN,    0 },
+		{ QSE_T("\\"),  1, TOK_IDIV,         0 },
+		{ QSE_T("%%="), 3, TOK_CONCAT_ASSN,  0 },
+		{ QSE_T("%%"),  2, TOK_CONCAT,       0 },
 		{ QSE_T("%="),  2, TOK_MOD_ASSN,     0 },
 		{ QSE_T("%"),   1, TOK_MOD,          0 },
-		{ QSE_T("~"),   1, TOK_TILDE,        0 },
+		{ QSE_T("~~"),  2, TOK_BNOT,         0 },
+		{ QSE_T("~"),   1, TOK_MA,           0 },
 		{ QSE_T("("),   1, TOK_LPAREN,       0 },
 		{ QSE_T(")"),   1, TOK_RPAREN,       0 },
 		{ QSE_T("{"),   1, TOK_LBRACE,       0 },
@@ -5898,6 +5901,7 @@ static int get_token_into (qse_awk_t* awk, qse_awk_tok_t* tok)
 {
 	qse_cint_t c;
 	int n;
+	int skip_semicolon_after_include = 0;
 
 retry:
 	do 
@@ -5920,7 +5924,9 @@ retry:
 		if (n <= -1) return -1;
 		if (n >= 1) 
 		{
-			awk->sio.last = awk->sio.inp->last;
+			/*awk->sio.last = awk->sio.inp->last;*/
+			/* mark that i'm retrying after end of an included file */
+			skip_semicolon_after_include = 1; 
 			goto retry;
 		}
 
@@ -5977,50 +5983,6 @@ retry:
 			QSE_STR_PTR(tok->name), 
 			QSE_STR_LEN(tok->name));
 		SET_TOKEN_TYPE (awk, tok, type);
-
-#if 0
-		if (type == TOK_IDENT)
-		{
-			qse_awk_sio_lxc_t lc;
-
-			while (c == QSE_T(':'));
-			{
-				lc = awk->sio.last;
-				GET_CHAR_TO (awk, c);
-				if (c == QSE_T(':'))
-				{
-					GET_CHAR_TO (awk, c);
-					if (c == QSE_T('_') || QSE_AWK_ISALPHA (awk, c))
-					{
-						do 
-						{
-							ADD_TOKEN_CHAR (awk, tok, c);
-							GET_CHAR_TO (awk, c);
-						} 
-						while (c == QSE_T('_') || 
-						       QSE_AWK_ISALPHA (awk, c) ||
-						       QSE_AWK_ISDIGIT (awk, c));
-
-						/* this set_token_type may get executed 
-						 * more than necessary if there are many
-						 * segments. but never mind */
-						SET_TOKEN_TYPE (awk, tok, TOK_SEGIDENT); 
-					}
-					else
-					{
-						/* TODO: return an error for the 
-						 *       incomplete segmented identifier */
-					}
-				}
-				else
-				{
-					unget_char (awk, &awk->sio.last);
-					awk->sio.last = lc;
-					break;
-				}
-			}
-		}
-#endif
 	}
 	else if (c == QSE_T('\"')) 
 	{
@@ -6044,11 +6006,26 @@ retry:
 			else
 			{
 				qse_char_t cc = (qse_char_t)c;
-				SETERR_ARG_LOC (
-					awk, QSE_AWK_ELXCHR, &cc, 1, &tok->loc);
+				SETERR_ARG_LOC (awk, QSE_AWK_ELXCHR, &cc, 1, &tok->loc);
 			}
 			return -1;
 		}
+
+		if (skip_semicolon_after_include && (tok->type == TOK_SEMICOLON || tok->type == TOK_NEWLINE))
+		{
+			/* this handles the optional semicolon after the 
+			 * included file named as in @include "file-name"; */
+			skip_semicolon_after_include = 0;
+			goto retry;
+		}
+	}
+
+	if (skip_semicolon_after_include && !(awk->opt.trait & QSE_AWK_NEWLINE))
+	{
+		/* semiclon has not been skipped yet and the 
+		 * newline option is not set. */
+		qse_awk_seterror (awk, QSE_AWK_ESCOLON, QSE_STR_CSTR(tok->name), &tok->loc);
+		return -1;
 	}
 
 	return 0;
diff --git a/qse/lib/awk/run.c b/qse/lib/awk/run.c
index 9ffd728e..dac7ca71 100644
--- a/qse/lib/awk/run.c
+++ b/qse/lib/awk/run.c
@@ -161,6 +161,11 @@ static qse_awk_val_t* eval_binop_bxor (
 	qse_awk_rtx_t* run, qse_awk_val_t* left, qse_awk_val_t* right);
 static qse_awk_val_t* eval_binop_band (
 	qse_awk_rtx_t* run, qse_awk_val_t* left, qse_awk_val_t* right);
+
+static qse_awk_val_t* eval_binop_teq (
+	qse_awk_rtx_t* run, qse_awk_val_t* left, qse_awk_val_t* right);
+static qse_awk_val_t* eval_binop_tne (
+	qse_awk_rtx_t* run, qse_awk_val_t* left, qse_awk_val_t* right);
 static qse_awk_val_t* eval_binop_eq (
 	qse_awk_rtx_t* run, qse_awk_val_t* left, qse_awk_val_t* right);
 static qse_awk_val_t* eval_binop_ne (
@@ -309,12 +314,12 @@ static int set_global (
 		/* once a variable becomes a map,
 		 * it cannot be changed to a scalar variable */
 
-		if (var != QSE_NULL)
+		if (var)
 		{
 			/* global variable */
 			SETERR_ARGX_LOC (
 				rtx,
-				QSE_AWK_EMAPTOSCALAR, 
+				QSE_AWK_EMAPNA, 
 				xstr_to_cstr(&var->id.name),
 				&var->loc
 			);
@@ -324,7 +329,7 @@ static int set_global (
 			/* qse_awk_rtx_setgbl has been called */
 			qse_cstr_t ea;
 			ea.ptr = qse_awk_getgblname (rtx->awk, idx, &ea.len);
-			SETERR_ARGX (rtx, QSE_AWK_EMAPTOSCALAR, &ea);
+			SETERR_ARGX (rtx, QSE_AWK_EMAPNA, &ea);
 		}
 
 		return -1;
@@ -656,7 +661,7 @@ int qse_awk_rtx_setofilename (
 	qse_awk_val_t* tmp;
 	int n;
 
-	if (rtx->awk->opt.trait & QSE_AWK_NEXTOFILE)
+	if (rtx->awk->opt.trait & QSE_AWK_EXTRAKWS)
 	{
 		if (len == 0) tmp = qse_awk_val_zls;
 		else
@@ -2319,8 +2324,7 @@ static int run_return (qse_awk_rtx_t* run, qse_awk_nde_return_t* nde)
 				/* cannot return a map */
 				qse_awk_rtx_refupval (run, val);
 				qse_awk_rtx_refdownval (run, val);
-
-				SETERR_LOC (run, QSE_AWK_EMAPNA, &nde->loc);
+				SETERR_LOC (run, QSE_AWK_EMAPPH, &nde->loc);
 				return -1;
 			}
 		}
@@ -2590,7 +2594,7 @@ static int run_delete_named (qse_awk_rtx_t* rtx, qse_awk_nde_var_t* var)
 	return 0;
 }
 
-static int run_delete_nonnamed (qse_awk_rtx_t* rtx, qse_awk_nde_var_t* var)
+static int run_delete_unnamed (qse_awk_rtx_t* rtx, qse_awk_nde_var_t* var)
 {
 	qse_awk_val_t* val;
 
@@ -2693,7 +2697,7 @@ static int run_delete (qse_awk_rtx_t* rtx, qse_awk_nde_delete_t* nde)
 		case QSE_AWK_NDE_GBLIDX:
 		case QSE_AWK_NDE_LCLIDX:
 		case QSE_AWK_NDE_ARGIDX:
-			return run_delete_nonnamed (rtx, var);
+			return run_delete_unnamed (rtx, var);
 
 		default:
 			QSE_ASSERTX (
@@ -3321,6 +3325,7 @@ static qse_awk_val_t* eval_assignment (qse_awk_rtx_t* run, qse_awk_nde_t* nde)
 		qse_awk_val_t* val2, * tmp;
 		static binop_func_t binop_func[] =
 		{
+			/* this table must match qse_awk_assop_type_t in run.h */
 			QSE_NULL, /* QSE_AWK_ASSOP_NONE */
 			eval_binop_plus,
 			eval_binop_minus,
@@ -3455,13 +3460,12 @@ static qse_awk_val_t* do_assignment_scalar (
 
 			pair = qse_htb_search (
 				run->named, var->id.name.ptr, var->id.name.len);
-			if (pair != QSE_NULL && 
-			    ((qse_awk_val_t*)QSE_HTB_VPTR(pair))->type == QSE_AWK_VAL_MAP)
+			if (pair && ((qse_awk_val_t*)QSE_HTB_VPTR(pair))->type == QSE_AWK_VAL_MAP)
 			{
 				/* once a variable becomes a map,
 				 * it cannot be changed to a scalar variable */
 				SETERR_ARGX_LOC (
-					run, QSE_AWK_EMAPTOSCALAR,
+					run, QSE_AWK_EMAPNA,
 					xstr_to_cstr(&var->id.name), &var->loc);
 				return QSE_NULL;
 			}
@@ -3495,7 +3499,7 @@ static qse_awk_val_t* do_assignment_scalar (
 				/* once the variable becomes a map,
 				 * it cannot be changed to a scalar variable */
 				SETERR_ARGX_LOC (
-					run, QSE_AWK_EMAPTOSCALAR, 
+					run, QSE_AWK_EMAPNA, 
 					xstr_to_cstr(&var->id.name), &var->loc);
 				return QSE_NULL;
 			}
@@ -3514,7 +3518,7 @@ static qse_awk_val_t* do_assignment_scalar (
 				/* once the variable becomes a map,
 				 * it cannot be changed to a scalar variable */
 				SETERR_ARGX_LOC (
-					run, QSE_AWK_EMAPTOSCALAR, 
+					run, QSE_AWK_EMAPNA, 
 					xstr_to_cstr(&var->id.name), &var->loc);
 				return QSE_NULL;
 			}
@@ -3718,6 +3722,8 @@ static qse_awk_val_t* eval_binary (qse_awk_rtx_t* run, qse_awk_nde_t* nde)
 		eval_binop_bxor,
 		eval_binop_band,
 
+		eval_binop_teq,
+		eval_binop_tne,
 		eval_binop_eq,
 		eval_binop_ne,
 		eval_binop_gt,
@@ -4338,28 +4344,67 @@ static int __cmp_val (
 	return func[left->type*4+right->type] (rtx, left, right);
 }
 
-static qse_awk_val_t* eval_binop_eq (
-	qse_awk_rtx_t* rtx, qse_awk_val_t* left, qse_awk_val_t* right)
+static int teq_val (qse_awk_rtx_t* rtx, qse_awk_val_t* left, qse_awk_val_t* right)
 {
 	int n;
 
-	if (left == right) 
+	if (left == right) n = 1;
+	else if (left->type != right->type) n = 0;
+	else
 	{
-		/* array comparison is not allowed but this special check
-		   allows comparsion of an array with itself. let's not
-		   care about this loophole. */
-		return qse_awk_val_one;
+		switch (left->type)
+		{
+			case QSE_AWK_VAL_NIL:
+				n = 1; 
+				break;
+
+			case QSE_AWK_VAL_INT:
+				n = ((qse_awk_val_int_t*)left)->val == 
+				    ((qse_awk_val_int_t*)right)->val;
+				break;
+
+			case QSE_AWK_VAL_FLT:
+				n = ((qse_awk_val_flt_t*)left)->val == 
+				    ((qse_awk_val_flt_t*)right)->val;
+				break;
+
+			case QSE_AWK_VAL_STR:
+				n = qse_strxncmp (
+					((qse_awk_val_str_t*)left)->val.ptr,
+					((qse_awk_val_str_t*)left)->val.len,
+					((qse_awk_val_str_t*)right)->val.ptr,
+					((qse_awk_val_str_t*)right)->val.len) == 0;
+				break;
+
+			default:
+				/* map-x and map-y are always different regardless of
+				 * their contents. however, if they are pointing to the
+				 * same map value, it won't reach here but will be 
+				 * handled by the first check in this function */
+				n = 0;
+				break;
+		}
 	}
 
-/*
-	if (left->type != right->type &&
-	    (left->type == QSE_AWK_VAL_MAP || right->type == QSE_AWK_VAL_MAP))
-	{
-		return qse_awk_val_zero;
-	}
-*/
+	return n;
+}
 
-	n = __cmp_val (rtx, left, right);
+static qse_awk_val_t* eval_binop_teq (
+	qse_awk_rtx_t* rtx, qse_awk_val_t* left, qse_awk_val_t* right)
+{
+	return teq_val (rtx, left, right)? qse_awk_val_one: qse_awk_val_zero;
+}
+
+static qse_awk_val_t* eval_binop_tne (
+	qse_awk_rtx_t* rtx, qse_awk_val_t* left, qse_awk_val_t* right)
+{
+	return teq_val (rtx, left, right)? qse_awk_val_zero: qse_awk_val_one;
+}
+
+static qse_awk_val_t* eval_binop_eq (
+	qse_awk_rtx_t* rtx, qse_awk_val_t* left, qse_awk_val_t* right)
+{
+	int n = __cmp_val (rtx, left, right);
 	if (n == CMP_ERROR) return QSE_NULL;
 	return (n == 0)? qse_awk_val_one: qse_awk_val_zero;
 }
@@ -4367,25 +4412,7 @@ static qse_awk_val_t* eval_binop_eq (
 static qse_awk_val_t* eval_binop_ne (
 	qse_awk_rtx_t* rtx, qse_awk_val_t* left, qse_awk_val_t* right)
 {
-	int n;
-
-	if (left == right)
-	{
-		/* array comparison is not allowed but this special check
-		   allows comparsion of an array with itself. let's not
-		   care about this loophole. */
-		return qse_awk_val_zero;
-	}
-
-/*
-	if (left->type != right->type &&
-	    (left->type == QSE_AWK_VAL_MAP || right->type == QSE_AWK_VAL_MAP))
-	{
-		return qse_awk_val_one;
-	}
-*/
-
-	n = __cmp_val (rtx, left, right);
+	int n = __cmp_val (rtx, left, right);
 	if (n == CMP_ERROR) return QSE_NULL;
 	return (n != 0)? qse_awk_val_one: qse_awk_val_zero;
 }
diff --git a/qse/lib/awk/run.h b/qse/lib/awk/run.h
index 3f3df00d..21be298d 100644
--- a/qse/lib/awk/run.h
+++ b/qse/lib/awk/run.h
@@ -24,7 +24,12 @@
 enum qse_awk_assop_type_t
 {
 	/* if you change this, you have to change assop_str in tree.c.
-	 * synchronize it with binop_func of eval_assignment in run.c */
+	 * synchronize it wit: 
+	 *   - binop_func in eval_assignment of run.c 
+	 *   - assop in assing_to_opcode of parse.c
+	 *   - TOK_XXX_ASSN in tok_t in parse.c
+	 *   - assop_str in tree.c
+	 */
 	QSE_AWK_ASSOP_NONE, 
 	QSE_AWK_ASSOP_PLUS,   /* += */
 	QSE_AWK_ASSOP_MINUS,  /* -= */
@@ -37,7 +42,7 @@ enum qse_awk_assop_type_t
 	QSE_AWK_ASSOP_RS,     /* >>= */
 	QSE_AWK_ASSOP_LS,     /* <<= */
 	QSE_AWK_ASSOP_BAND,   /* &= */
-	QSE_AWK_ASSOP_BXOR,   /* ^= */
+	QSE_AWK_ASSOP_BXOR,   /* ^^= */
 	QSE_AWK_ASSOP_BOR     /* |= */
 };
 
@@ -53,6 +58,8 @@ enum  qse_awk_binop_type_t
 	QSE_AWK_BINOP_BXOR,
 	QSE_AWK_BINOP_BAND,
 
+	QSE_AWK_BINOP_TEQ,
+	QSE_AWK_BINOP_TNE,
 	QSE_AWK_BINOP_EQ,
 	QSE_AWK_BINOP_NE,
 	QSE_AWK_BINOP_GT,
diff --git a/qse/lib/awk/tree.c b/qse/lib/awk/tree.c
index 876b2c89..5e7c468c 100644
--- a/qse/lib/awk/tree.c
+++ b/qse/lib/awk/tree.c
@@ -23,6 +23,7 @@
 
 static const qse_char_t* assop_str[] =
 {
+	/* this table must match qse_awk_assop_type_t in run.h */
 	QSE_T("="),
 	QSE_T("+="),
 	QSE_T("-="),
@@ -30,11 +31,12 @@ static const qse_char_t* assop_str[] =
 	QSE_T("/="),
 	QSE_T("\\="),
 	QSE_T("%="),
-	QSE_T("**="),
+	QSE_T("**="), /* exponentation, also ^= */
+	QSE_T("%%="),
 	QSE_T(">>="),
 	QSE_T("<<="),
 	QSE_T("&="),
-	QSE_T("^="),
+	QSE_T("^^="),
 	QSE_T("|=")
 };
 
@@ -45,9 +47,11 @@ static const qse_char_t* binop_str[][2] =
 	{ QSE_T("in"), QSE_T("in") },
 
 	{ QSE_T("|"),  QSE_T("|") },
-	{ QSE_T("^"),  QSE_T("^") },
+	{ QSE_T("^^"), QSE_T("^^") },
 	{ QSE_T("&"),  QSE_T("&") },
 
+	{ QSE_T("==="), QSE_T("===") },
+	{ QSE_T("!=="), QSE_T("!==") },
 	{ QSE_T("=="), QSE_T("==") },
 	{ QSE_T("!="), QSE_T("!=") },
 	{ QSE_T(">"),  QSE_T(">") },
@@ -64,9 +68,9 @@ static const qse_char_t* binop_str[][2] =
 	{ QSE_T("/"),  QSE_T("/") },
 	{ QSE_T("\\"), QSE_T("\\") },
 	{ QSE_T("%"),  QSE_T("%") },
-	{ QSE_T("**"), QSE_T("**") },
+	{ QSE_T("**"), QSE_T("**") }, /* exponentation, also ^ */
 
-	{ QSE_T(" "),  QSE_T(".") },
+	{ QSE_T(" "),  QSE_T("%%") }, /* take note of this entry */
 	{ QSE_T("~"),  QSE_T("~") },
 	{ QSE_T("!~"), QSE_T("!~") }
 };
@@ -76,7 +80,7 @@ static const qse_char_t* unrop_str[] =
 	QSE_T("+"),
 	QSE_T("-"),
 	QSE_T("!"),
-	QSE_T("~")
+	QSE_T("~~")
 };
 
 static const qse_char_t* incop_str[] =
diff --git a/qse/mod/awk/uci.c b/qse/mod/awk/uci.c
index 4fb4d42a..ca6d4f31 100644
--- a/qse/mod/awk/uci.c
+++ b/qse/mod/awk/uci.c
@@ -106,7 +106,7 @@ static void free_uctx_node (qse_awk_rtx_t* rtx, uctx_list_t* list, uctx_node_t*
 
 	list->map.tab[node->id] = QSE_NULL;
 
-	uci_free_context (node->ctx);
+	if (node->ctx) uci_free_context (node->ctx);
 
 	if (list->map.high == node->id + 1)
 	{
@@ -118,6 +118,7 @@ static void free_uctx_node (qse_awk_rtx_t* rtx, uctx_list_t* list, uctx_node_t*
 	else
 	{
 		/* otherwise, chain the node to the free list */
+		node->ctx = QSE_NULL;
 		node->next = list->free;
 		list->free = node;
 	}
@@ -135,7 +136,7 @@ static void free_uctx_node (qse_awk_rtx_t* rtx, uctx_list_t* list, uctx_node_t*
 		{
 			curnode = list->free;
 			list->free = list->free->next;
-			uci_free_context (curnode->ctx);
+			QSE_ASSERT (curnode->ctx == QSE_NULL);
 			QSE_MMGR_FREE (mmgr, curnode);
 		}
 
diff --git a/qse/regress/awk/regress.sh.in b/qse/regress/awk/regress.sh.in
index fc7a4ab9..0bbcd05c 100755
--- a/qse/regress/awk/regress.sh.in
+++ b/qse/regress/awk/regress.sh.in
@@ -174,11 +174,11 @@ PROGS="
 	lang-045.awk!!!--newline=on -d-
 	lang-046.awk!lang-046.dat2!!--newline=on -d- -vdatadir=@abs_srcdir@ -vdatafile=lang-046.dat1
 	lang-047.awk!!!--newline=on --tolerant=on -d-
-	lang-048.awk!!!--newline=on --extraops=on -d-
+	lang-048.awk!!!--newline=on -d-
 	lang-049.awk!!!--newline=on -d-
 
 	columnate.awk!passwd.dat!!--newline=on -F:
-	levenshtein-utests.awk!!!--newline=on --include=on
+	levenshtein-utests.awk!!!--newline=on --extrakws=on
 	rcalc.awk!!!--newline=on -v target=89000
 	quicksort.awk!quicksort.dat!!
 	quicksort2.awk!quicksort2.dat!!-vQSEAWK=\"${QSEAWK}\" -vSCRIPT_PATH=\"${SCRIPT_DIR}\"
diff --git a/qse/samples/awk/awk04.c b/qse/samples/awk/awk04.c
index bc948808..c5d30dc3 100644
--- a/qse/samples/awk/awk04.c
+++ b/qse/samples/awk/awk04.c
@@ -53,7 +53,6 @@ int main ()
 	/* don't allow BEGIN, END, pattern-action blocks */
 	opt &= ~QSE_AWK_PABLOCK;
 	/* enable ** */
-	opt |= QSE_AWK_EXTRAOPS;
      qse_awk_setopt (awk, QSE_AWK_TRAIT, &opt);
 
 
diff --git a/qse/samples/awk/awk07.cpp b/qse/samples/awk/awk07.cpp
index 2fcc5def..789cdffb 100644
--- a/qse/samples/awk/awk07.cpp
+++ b/qse/samples/awk/awk07.cpp
@@ -139,7 +139,7 @@ static int awk_main (int argc, qse_char_t* argv[])
 	awk.setTrait (
 		awk.getTrait() | 
 		QSE_AWK_MAPTOVAR |
-		QSE_AWK_RESET);
+		QSE_AWK_EXTRAKWS);
 
 	if (ret >= 0) ret = run_awk (awk);
 	if (ret <= -1) 
diff --git a/qse/samples/awk/awk08.cpp b/qse/samples/awk/awk08.cpp
index 30b6b018..f93e9960 100644
--- a/qse/samples/awk/awk08.cpp
+++ b/qse/samples/awk/awk08.cpp
@@ -356,8 +356,7 @@ static int awk_main_2 (MyAwk& awk, int argc, qse_char_t* argv[])
 	cmdline_t cmdline;
 	int n;
 
-	awk.setTrait (awk.getTrait() | QSE_AWK_INCLUDE | 
-		QSE_AWK_MAPTOVAR | QSE_AWK_RWPIPE | QSE_AWK_EXTRAOPS);
+	awk.setTrait (awk.getTrait() | QSE_AWK_EXTRAKWS | QSE_AWK_MAPTOVAR | QSE_AWK_RWPIPE);
 
 	// ARGV[0]
 	if (awk.addArgument (QSE_T("awk08")) <= -1)
diff --git a/qse/samples/awk/awk09.c b/qse/samples/awk/awk09.c
index 4ed38d52..1d31a75d 100644
--- a/qse/samples/awk/awk09.c
+++ b/qse/samples/awk/awk09.c
@@ -64,7 +64,7 @@ int main ()
 	}
 
 	qse_awk_getopt (awk, QSE_AWK_TRAIT, &opt);
-	opt |= QSE_AWK_NEXTOFILE;
+	opt |= QSE_AWK_EXTRAKWS;
 	qse_awk_setopt (awk, QSE_AWK_TRAIT, &opt);
 
 	psin.type = QSE_AWK_PARSESTD_STR;
diff --git a/qse/samples/awk/awk10.c b/qse/samples/awk/awk10.c
index c72f8c9c..5c099d60 100644
--- a/qse/samples/awk/awk10.c
+++ b/qse/samples/awk/awk10.c
@@ -59,8 +59,6 @@ int main ()
 	opt &= ~QSE_AWK_PABLOCK;
 	/* can assign a map to a variable */
 	opt |= QSE_AWK_MAPTOVAR;
-	/* enable ** */
-	opt |= QSE_AWK_EXTRAOPS;
 	qse_awk_setopt (awk, QSE_AWK_TRAIT, &opt);
 
 	psin.type = QSE_AWK_PARSESTD_STR;