diff --git a/qse/cmd/awk/awk.c b/qse/cmd/awk/awk.c
index 9bb90e7f..65b35892 100644
--- a/qse/cmd/awk/awk.c
+++ b/qse/cmd/awk/awk.c
@@ -232,7 +232,6 @@ static struct
 	{ QSE_T("rio"),         QSE_AWK_RIO },
 	{ QSE_T("rwpipe"),      QSE_AWK_RWPIPE },
 	{ QSE_T("newline"),     QSE_AWK_NEWLINE },
-	{ QSE_T("baseone"),     QSE_AWK_BASEONE },
 	{ QSE_T("stripspaces"), QSE_AWK_STRIPSPACES },
 	{ QSE_T("nextofile"),   QSE_AWK_NEXTOFILE },
 	{ QSE_T("crfl"),        QSE_AWK_CRLF },
diff --git a/qse/include/qse/awk/Awk.hpp b/qse/include/qse/awk/Awk.hpp
index 8964b536..c7290865 100644
--- a/qse/include/qse/awk/Awk.hpp
+++ b/qse/include/qse/awk/Awk.hpp
@@ -574,7 +574,6 @@ public:
 		/** Can terminate a statement with a new line */
 		OPT_NEWLINE = QSE_AWK_NEWLINE,
 
-		OPT_BASEONE = QSE_AWK_BASEONE,
 		OPT_STRIPSPACES = QSE_AWK_STRIPSPACES,
 
 		/** Support the nextofile statement */
diff --git a/qse/include/qse/awk/awk.h b/qse/include/qse/awk/awk.h
index 4eaba1af..43b31bcd 100644
--- a/qse/include/qse/awk/awk.h
+++ b/qse/include/qse/awk/awk.h
@@ -261,9 +261,6 @@ enum qse_awk_option_t
 	/* can terminate a statement with a new line */
 	QSE_AWK_NEWLINE     = (1 << 9),
 
-	/* use 1 as the start index for string operations and ARGV */
-	QSE_AWK_BASEONE     = (1 << 10),
-
 	/* strip off leading and trailing spaces when splitting a record
 	 * into fields with a regular expression.
 	 *
@@ -292,7 +289,11 @@ enum qse_awk_option_t
 	QSE_AWK_MAPTOVAR    = (1 << 15),
 
 	/* allows BEGIN, END, pattern-action blocks */
-	QSE_AWK_PABLOCK     = (1 << 16)
+	QSE_AWK_PABLOCK     = (1 << 16),
+
+	/* option aggregtes */
+	QSE_AWK_CLASSIC  = QSE_AWK_IMPLICIT | QSE_AWK_RIO | 
+	                   QSE_AWK_NEWLINE | QSE_AWK_PABLOCK
 };
 
 /* error code */
diff --git a/qse/lib/awk/Awk.cpp b/qse/lib/awk/Awk.cpp
index f51d4b06..40d1dcc7 100644
--- a/qse/lib/awk/Awk.cpp
+++ b/qse/lib/awk/Awk.cpp
@@ -1225,14 +1225,6 @@ int Awk::open ()
 	qse_map_setfreeer (functionMap, QSE_MAP_VAL, freeFunctionMapValue);
 	qse_map_setscale (functionMap, QSE_MAP_KEY, QSE_SIZEOF(qse_char_t));
 
-	int opt = 
-		OPT_IMPLICIT |
-		OPT_RIO | 
-		OPT_NEWLINE | 
-		OPT_BASEONE |
-		OPT_PABLOCK;
-	qse_awk_setoption (awk, opt);
-
 	runCallback = false;
 	return 0;
 }
diff --git a/qse/lib/awk/awk.c b/qse/lib/awk/awk.c
index 3c1237ae..b734a5c4 100644
--- a/qse/lib/awk/awk.c
+++ b/qse/lib/awk/awk.c
@@ -150,7 +150,7 @@ qse_awk_t* qse_awk_open (qse_mmgr_t* mmgr, qse_size_t xtn, qse_awk_prm_t* prm)
 	qse_lda_setcopier (awk->parse.params, QSE_LDA_COPIER_INLINE);
 	qse_lda_setscale (awk->parse.params, QSE_SIZEOF(qse_char_t));
 
-	awk->option = 0;
+	awk->option = QSE_AWK_CLASSIC;
 	awk->errnum = QSE_AWK_ENOERR;
 	awk->errlin = 0;
 	awk->stopall = QSE_FALSE;
@@ -364,7 +364,6 @@ void qse_awk_setoption (qse_awk_t* awk, int opt)
 	awk->option = opt;
 }
 
-
 void qse_awk_stopall (qse_awk_t* awk)
 {
 	awk->stopall = QSE_TRUE;
diff --git a/qse/lib/awk/fnc.c b/qse/lib/awk/fnc.c
index dc54e5bf..da8d521b 100644
--- a/qse/lib/awk/fnc.c
+++ b/qse/lib/awk/fnc.c
@@ -459,9 +459,7 @@ static int fnc_index (
 	}
 
 	ptr = qse_strxnstr (str0, len0, str1, len1);
-	idx = (ptr == QSE_NULL)? -1: (qse_long_t)(ptr - str0);
-
-	if (qse_awk_getoption(run->awk) & QSE_AWK_BASEONE) idx = idx + 1;
+	idx = (ptr == QSE_NULL)? 0: ((qse_long_t)(ptr-str0) + 1);
 
 	if (a0->type != QSE_AWK_VAL_STR) QSE_AWK_FREE (run->awk, str0);
 	if (a1->type != QSE_AWK_VAL_STR) QSE_AWK_FREE (run->awk, str1);
@@ -563,7 +561,7 @@ static int fnc_substr (
 		if (n == 1) lcount = (qse_long_t)rcount;
 	}
 
-	if (qse_awk_getoption(run->awk) & QSE_AWK_BASEONE) lindex = lindex - 1;
+	lindex = lindex - 1;
 	if (lindex >= (qse_long_t)len) lindex = (qse_long_t)len;
 	else if (lindex < 0) lindex = 0;
 
@@ -593,7 +591,7 @@ static int fnc_split (
 	qse_awk_val_t* a0, * a1, * a2, * t1, * t2, ** a1_ref;
 	qse_char_t* str, * str_free, * p, * tok;
 	qse_size_t str_len, str_left, tok_len;
-	qse_long_t sta, num;
+	qse_long_t num;
 	qse_char_t key[QSE_SIZEOF(qse_long_t)*8+2];
 	qse_size_t key_len;
 	qse_char_t* fs_ptr, * fs_free;
@@ -740,8 +738,7 @@ static int fnc_split (
 	qse_awk_rtx_refupval (run, *a1_ref);
 
 	p = str; str_left = str_len; 
-	sta = (qse_awk_getoption(run->awk) & QSE_AWK_BASEONE)? 1: 0;
-	num = sta;
+	num = 1;
 
 	while (p != QSE_NULL)
 	{
@@ -830,7 +827,7 @@ static int fnc_split (
 	if (fs_free != QSE_NULL) QSE_AWK_FREE (run->awk, fs_free);
 	if (fs_rex_free != QSE_NULL) QSE_AWK_FREEREX (run->awk, fs_rex_free);
 
-	if (sta == 1) num--;
+	num--;
 
 	t1 = qse_awk_rtx_makeintval (run, num);
 	if (t1 == QSE_NULL)
@@ -1301,8 +1298,7 @@ static int fnc_match (
 
 	if (n == -1) return -1;
 
-	idx = (n == 0)? -1: (qse_long_t)(mat_ptr - str0);
-	if (qse_awk_getoption(run->awk) & QSE_AWK_BASEONE) idx = idx + 1;
+	idx = (n == 0)? 0: ((qse_long_t)(mat_ptr-str0) + 1);
 
 	a0 = qse_awk_rtx_makeintval (run, idx);
 	if (a0 == QSE_NULL)
diff --git a/qse/lib/awk/run.c b/qse/lib/awk/run.c
index abff5657..1302ff0e 100644
--- a/qse/lib/awk/run.c
+++ b/qse/lib/awk/run.c
@@ -1005,16 +1005,8 @@ static int build_runarg (
 				return -1;
 			}
 
-			if (qse_awk_getoption(run->awk) & QSE_AWK_BASEONE)
-			{
-				key_len = qse_awk_longtostr (argc+1, 
-					10, QSE_NULL, key, QSE_COUNTOF(key));
-			}
-			else
-			{
-				key_len = qse_awk_longtostr (argc, 
-					10, QSE_NULL, key, QSE_COUNTOF(key));
-			}
+			key_len = qse_awk_longtostr (argc+1, 
+				10, QSE_NULL, key, QSE_COUNTOF(key));
 			QSE_ASSERT (key_len != (qse_size_t)-1);
 
 			/* increment reference count of v_tmp in advance as if 
diff --git a/qse/lib/awk/std.c b/qse/lib/awk/std.c
index da0c8a41..9183837e 100644
--- a/qse/lib/awk/std.c
+++ b/qse/lib/awk/std.c
@@ -38,7 +38,7 @@ typedef struct xtn_t
 			{
 				const qse_char_t*const* files; 
 				const qse_char_t* str;
-			} p;
+			} u;
 			qse_size_t              index;  /* current file index */
 			qse_sio_t*              handle; /* the handle to an open file */
 		} in;
@@ -60,13 +60,13 @@ typedef struct rxtn_t
 	struct
 	{
 		struct {
-			const qse_char_t** files;
+			const qse_char_t*const* files;
 			qse_size_t index;
 		} in; 
 
 		struct 
 		{
-			const qse_char_t** files;
+			const qse_char_t*const* files;
 			qse_size_t index;
 		} out;
 	} c;  /* console */
@@ -142,9 +142,7 @@ qse_awk_t* qse_awk_opensimple (void)
 	QSE_MEMSET (xtn, 0, QSE_SIZEOF(xtn_t));
 
 	/* set default options */
-	qse_awk_setoption (awk, 
-		QSE_AWK_IMPLICIT | QSE_AWK_RIO | QSE_AWK_NEWLINE | 
-		QSE_AWK_BASEONE | QSE_AWK_PABLOCK);
+	qse_awk_setoption (awk, QSE_AWK_CLASSIC);
 
 	/* add intrinsic functions */
 	if (add_functions (awk) == -1)
@@ -168,9 +166,10 @@ static qse_ssize_t sf_in (
 	{
 		if (xtn->s.in.type == QSE_AWK_SOURCE_FILES)
 		{
-			if (xtn->s.in.p.files[xtn->s.in.index] == QSE_NULL) return 0;
+			if (xtn->s.in.u.files == QSE_NULL) return -1;
+			if (xtn->s.in.u.files[xtn->s.in.index] == QSE_NULL) return 0;
 
-			if (xtn->s.in.p.files[xtn->s.in.index][0] == QSE_T('\0'))
+			if (xtn->s.in.u.files[xtn->s.in.index][0] == QSE_T('\0'))
 			{
 				xtn->s.in.handle = qse_sio_in;
 			}
@@ -179,15 +178,13 @@ static qse_ssize_t sf_in (
 				xtn->s.in.handle = qse_sio_open (
 					awk->mmgr,
 					0,
-					xtn->s.in.p.files[xtn->s.in.index],
+					xtn->s.in.u.files[xtn->s.in.index],
 					QSE_SIO_READ
 				);
 				if (xtn->s.in.handle == QSE_NULL) return -1;
 			}
 
-			/*
-			qse_awk_setsinname ();
-			*/
+			//qse_awk_setsource (awk, xtn->s.in.u.files[xtn->s.in.index]);
 		}
 
 		return 1;
@@ -216,10 +213,10 @@ static qse_ssize_t sf_in (
 			sio = xtn->s.in.handle;
 
 			n = qse_sio_getsn (sio, data, size);
-			if (n == 0 && xtn->s.in.p.files[++xtn->s.in.index] != QSE_NULL)
+			if (n == 0 && xtn->s.in.u.files[++xtn->s.in.index] != QSE_NULL)
 			{
 				if (sio != qse_sio_in) qse_sio_close (sio);
-				if (xtn->s.in.p.files[xtn->s.in.index][0] == QSE_T('\0'))
+				if (xtn->s.in.u.files[xtn->s.in.index][0] == QSE_T('\0'))
 				{
 					xtn->s.in.handle = qse_sio_in;
 				}
@@ -228,7 +225,7 @@ static qse_ssize_t sf_in (
 					xtn->s.in.handle = qse_sio_open (
 						awk->mmgr,
 						0,
-						xtn->s.in.p.files[xtn->s.in.index],
+						xtn->s.in.u.files[xtn->s.in.index],
 						QSE_SIO_READ
 					);
 					if (xtn->s.in.handle == QSE_NULL) return -1;
@@ -244,9 +241,9 @@ static qse_ssize_t sf_in (
 		}
 		else
 		{
-			while (n < size && xtn->s.in.p.str[xtn->s.in.index] != QSE_T('\0'))
+			while (n < size && xtn->s.in.u.str[xtn->s.in.index] != QSE_T('\0'))
 			{
-				data[n++] = xtn->s.in.p.str[xtn->s.in.index++];
+				data[n++] = xtn->s.in.u.str[xtn->s.in.index++];
 			}
 		}
 
@@ -318,11 +315,11 @@ int qse_awk_parsesimple (
 
 	if (ist == QSE_AWK_SOURCE_FILES) 
 	{
-		xtn->s.in.p.files = (const qse_char_t* const*)isp;
+		xtn->s.in.u.files = (const qse_char_t*const*)isp;
 	}
 	else if (ist == QSE_AWK_SOURCE_STRING) 
 	{
-		xtn->s.in.p.str = (const qse_char_t*)isp;
+		xtn->s.in.u.str = (const qse_char_t*)isp;
 	}
 	else
 	{