diff --git a/hawk/lib/fnc.c b/hawk/lib/fnc.c
index 3dd8caec..af8da7f1 100644
--- a/hawk/lib/fnc.c
+++ b/hawk/lib/fnc.c
@@ -1093,8 +1093,23 @@ static int __substitute_oocs (hawk_rtx_t* rtx, hawk_oow_t* max_count, hawk_tre_t
 
 		for (i = 0; i < s1->len; i++)
 		{
-			if ((i+1) < s1->len && s1->ptr[i] == '\\' && s1->ptr[i+1] == '&')
+			if ((i + 3) < s1->len && s1->ptr[i] == '\\' && s1->ptr[i+1] == '\\' && s1->ptr[i+2] == '\\' && s1->ptr[i+3] == '&')
 			{
+				/* \\\& to produce a literal \& */
+				m = hawk_ooecs_cat(new, HAWK_T("\\&"));
+				i += 3;
+			}
+			else if ((i + 2) < s1->len && s1->ptr[i] == '\\' && s1->ptr[i+1] == '\\' && s1->ptr[i+2] == '&')
+			{
+				/* \\& to produce a literal \ followed by the matched text */
+				m = hawk_ooecs_ccat(new, '\\');
+				if (HAWK_UNLIKELY(m == (hawk_oow_t)-1)) goto oops;
+				m = hawk_ooecs_ncat(new, mat.ptr, mat.len);
+				i += 2;
+			}
+			else if ((i + 1) < s1->len && s1->ptr[i] == '\\' && s1->ptr[i+1] == '&')
+			{
+				/* \& to produce literal '&' */
 				m = hawk_ooecs_ccat(new, '&');
 				i++;
 			}
@@ -1183,8 +1198,23 @@ static int __substitute_bcs (hawk_rtx_t* rtx, hawk_oow_t* max_count, hawk_tre_t*
 
 		for (i = 0; i < s1->len; i++)
 		{
-			if ((i+1) < s1->len && s1->ptr[i] == '\\' && s1->ptr[i+1] == '&')
+			if ((i + 3) < s1->len && s1->ptr[i] == '\\' && s1->ptr[i+1] == '\\' && s1->ptr[i+2] == '\\' && s1->ptr[i+3] == '&')
 			{
+				/* \\\& to produce a literal \& */
+				m = hawk_becs_cat(new, "\\&");
+				i += 3;
+			}
+			else if ((i + 2) < s1->len && s1->ptr[i] == '\\' && s1->ptr[i+1] == '\\' && s1->ptr[i+2] == '&')
+			{
+				/* \\& to produce a literal \ followed by the matched text */
+				m = hawk_becs_ccat(new, '\\');
+				if (HAWK_UNLIKELY(m == (hawk_oow_t)-1)) goto oops;
+				m = hawk_becs_ncat(new, mat.ptr, mat.len);
+				i += 2;
+			}
+			else if ((i + 1) < s1->len && s1->ptr[i] == '\\' && s1->ptr[i+1] == '&')
+			{
+				/* \& to produce literal '&' */
 				m = hawk_becs_ccat(new, '&');
 				i++;
 			}
@@ -1455,7 +1485,7 @@ int hawk_fnc_match (hawk_rtx_t* rtx, const hawk_fnc_info_t* fi)
 	for (i = 1; i <= q; i++) print x[i,"start"], x[i,"length"]; 
 	print RSTART, RLENGTH;
 	* ------------------------------------
-	match(B"ab\xB0\x98cdefgdefx", /(def)g(.+)/, 1, x); 
+	match(@b"ab\xB0\x98cdefgdefx", /(def)g(.+)/, 1, x); 
 	q = length(x) / 2;
 	for (i = 1; i <= q; i++) print x[i,"start"], x[i,"length"]; 
 	print RSTART, RLENGTH;
diff --git a/hawk/lib/mod-str.c b/hawk/lib/mod-str.c
index f4866f9e..5cb130fd 100644
--- a/hawk/lib/mod-str.c
+++ b/hawk/lib/mod-str.c
@@ -352,10 +352,10 @@ static int fnc_tocharcode (hawk_rtx_t* rtx, const hawk_fnc_info_t* fi)
 
 static int fnc_frommbs (hawk_rtx_t* rtx, const hawk_fnc_info_t* fi)
 {
-	/* str::frommbs(B"byte-string" [, "encoding-name"])
+	/* str::frommbs(@b"byte-string" [, "encoding-name"])
 	 * 
 	 * if you use a supported encoding name, it may look like this:
-	 *   a = str::frommbs(B"\xC7\xD1\xB1\xDB", "cp949");
+	 *   a = str::frommbs(@b"\xC7\xD1\xB1\xDB", "cp949");
 	 *   printf ("%K\n", a);
 	 */
 	hawk_val_t* a0, * r;
@@ -413,7 +413,7 @@ static int fnc_tombs (hawk_rtx_t* rtx, const hawk_fnc_info_t* fi)
 	 * 
 	 * if you use a supported encoding name, it may look like this:
 	 *   a = str::tombs("\uD55C\uAE00", "cp949"); 
-	 *   printf (B"%K\n", a); 
+	 *   printf (@b"%K\n", a); 
 	 */
 
 	hawk_val_t* a0, * r;
diff --git a/hawk/lib/mod-sys.c b/hawk/lib/mod-sys.c
index ebb626a0..6fd85d6b 100644
--- a/hawk/lib/mod-sys.c
+++ b/hawk/lib/mod-sys.c
@@ -580,7 +580,7 @@ static int fnc_close (hawk_rtx_t* rtx, const hawk_fnc_info_t* fi)
 /*
   BEGIN {
      f = sys::open("/tmp/test.txt", sys::O_RDONLY);
-     while (sys::read(f, x, 10) > 0) printf (B"%s", x);
+     while (sys::read(f, x, 10) > 0) printf (@b"%s", x);
      sys::close (f);
   }
 */
@@ -642,7 +642,7 @@ static int fnc_open (hawk_rtx_t* rtx, const hawk_fnc_info_t* fi)
 
 /*
 	a = sys::openfd(1);
-	sys::write (a, B"let me write something here\n");
+	sys::write (a, @b"let me write something here\n");
 	sys::close (a, sys::C_KEEPFD); ## set C_KEEPFD to release 1 without closing it.
 	##sys::close (a);
 	print "done\n";
@@ -874,7 +874,7 @@ static int fnc_write (hawk_rtx_t* rtx, const hawk_fnc_info_t* fi)
 	b = sys::dup(a);
 	sys::close(a);
 
-	while (sys::read(b, abc, 100) > 0) printf (B"%s", abc);
+	while (sys::read(b, abc, 100) > 0) printf (@b"%s", abc);
 
 	print "-------------------------------";
 
@@ -882,7 +882,7 @@ static int fnc_write (hawk_rtx_t* rtx, const hawk_fnc_info_t* fi)
 	## assertion: b == c
 	sys::close (x);
 
-	while (sys::read(c, abc, 100) > 0) printf (B"%s", abc);
+	while (sys::read(c, abc, 100) > 0) printf (@b"%s", abc);
 	sys::close (c);
 */
 
@@ -1265,7 +1265,7 @@ BEGIN {
         a["lflag"] &= ~sys::TC_LFLAG_ECHO;
         sys::tcsetattr(IN, 0, a);
         printf ("Password:");
-        ##sys::write (OUT, B"Password:");
+        ##sys::write (OUT, @b"Password:");
         getline x;
         a["lflag"] |= sys::TC_LFLAG_ECHO;
         sys::tcsetattr(IN, 0, a);
@@ -1492,8 +1492,8 @@ done:
 		## parent
 		printf ("parent.... %d %d %d\n", sys::getpid(), p0, p1);
 		sys::close (p0);
-		sys::write (p1, B"hello");
-		sys::write (p1, B"world");
+		sys::write (p1, @b"hello");
+		sys::write (p1, @b"world");
 		sys::close (p1);
 		sys::wait(a);
 	}##if (sys::pipe(p0, p1) <= -1)
@@ -1532,8 +1532,8 @@ done:
 		## parent
 		printf ("parent.... %d %d %d\n", sys::getpid(), p0, p1);
 		sys::close (p0);
-		sys::write (p1, B"hello");
-		sys::write (p1, B"world");
+		sys::write (p1, @b"hello");
+		sys::write (p1, @b"world");
 		sys::close (p1);
 		sys::wait(a);
 	}
diff --git a/hawk/lib/parse.c b/hawk/lib/parse.c
index e6bb4d99..635cd90c 100644
--- a/hawk/lib/parse.c
+++ b/hawk/lib/parse.c
@@ -6104,7 +6104,7 @@ static int get_string (
 	#if defined(HAWK_OOCH_IS_BCH)
 		/* nothing extra to handle byte_only */
 	#else
-		if (byte_only && c != HAWK_T('\\') && !HAWK_BYTE_PRINTABLE(c))
+		if (byte_only && c != '\\' && !HAWK_BYTE_PRINTABLE(c))
 		{
 			hawk_seterrfmt (hawk, &hawk->tok.loc, HAWK_EMBSCHR, HAWK_T("invalid mbs character '%jc'"), (hawk_ooch_t)c);
 			return -1;
@@ -6330,7 +6330,7 @@ static int get_rexstr (hawk_t* hawk, hawk_tok_t* tok)
 }
 
 
-static int get_single_quoted_string (hawk_t* hawk, int byte_only, hawk_tok_t* tok)
+static int get_raw_string (hawk_t* hawk, hawk_ooch_t end_char, int byte_only, hawk_tok_t* tok)
 {
 	hawk_ooci_t c;
 
@@ -6347,14 +6347,14 @@ static int get_single_quoted_string (hawk_t* hawk, int byte_only, hawk_tok_t* to
 	#if defined(HAWK_OOCH_IS_BCH)
 		/* nothing extra to handle byte_only */
 	#else
-		if (byte_only && c != HAWK_T('\\') && !HAWK_BYTE_PRINTABLE(c))
+		if (byte_only && c != '\\' && !HAWK_BYTE_PRINTABLE(c))
 		{
 			hawk_seterrfmt (hawk, &hawk->tok.loc, HAWK_EMBSCHR, HAWK_T("invalid mbs character '%jc'"), (hawk_ooch_t)c);
 			return -1;
 		}
 	#endif
 
-		if (c == HAWK_T('\''))
+		if (c == end_char)
 		{
 			/* terminating quote */
 			GET_CHAR (hawk);
@@ -6668,7 +6668,6 @@ retry:
 	{
 		int type;
 
-		ADD_TOKEN_CHAR (hawk, tok, c);
 		GET_CHAR_TO (hawk, c);
 
 		if (c != HAWK_T('_') && !hawk_is_ooch_alpha(c))
@@ -6678,8 +6677,100 @@ retry:
 			hawk_seterrnum (hawk, &(hawk)->tok.loc, HAWK_EXKWEM);
 			return -1;
 		}
+
+		if (c == 'B' || c == 'b')
+		{
+			hawk_sio_lxc_t pc1 = hawk->sio.last;
+			GET_CHAR_TO (hawk, c);
+			if (c == 'R' || c == 'r')
+			{
+				hawk_sio_lxc_t pc2 = hawk->sio.last;
+				GET_CHAR_TO (hawk, c);
+				if (c == '\"')
+				{
+					/* raw byte string */
+					SET_TOKEN_TYPE (hawk, tok, TOK_MBS);
+					if (get_raw_string(hawk, c, 1, tok) <= -1) return -1;
+				}
+				else
+				{
+					unget_char (hawk, &hawk->sio.last);
+					unget_char (hawk, &pc2);
+					hawk->sio.last = pc1;
+					c = pc1.c;
+					goto process_at_identifier;
+				}
+			}
+			else if (c == '\"')
+			{
+				/* B, b - byte string */
+				SET_TOKEN_TYPE (hawk, tok, TOK_MBS);
+				if (get_string(hawk, c, HAWK_T('\\'), 0, 1, 0, tok) <= -1) return -1;
+			}
+	#if 0
+			
+			else if (c == '\'')
+			{
+				/* TODO: character literal when I add a character type?? */
+			}
+	#endif
+			else
+			{
+				unget_char (hawk, &hawk->sio.last);
+				hawk->sio.last = pc1;
+				c = pc1.c;
+				goto process_at_identifier;
+			}
+		}
+		else if (c == 'R' || c == 'r')
+		{
+			hawk_sio_lxc_t pc1 = hawk->sio.last;
+			GET_CHAR_TO (hawk, c);
+			if (c == 'B' || c == 'b')
+			{
+				hawk_sio_lxc_t pc2 = hawk->sio.last;
+				GET_CHAR_TO (hawk, c);
+				if (c == '\"')
+				{
+					/* raw byte string */
+					SET_TOKEN_TYPE (hawk, tok, TOK_MBS);
+					if (get_raw_string(hawk, c, 1, tok) <= -1) return -1;
+				}
+				else
+				{
+					unget_char (hawk, &hawk->sio.last);
+					unget_char (hawk, &pc2);
+					hawk->sio.last = pc1;
+					c = pc1.c;
+					goto process_at_identifier;
+				}
+			}
+			else if (c == '\"')
+			{
+				/* R, r - raw string */
+				SET_TOKEN_TYPE (hawk, tok, TOK_STR);
+				if (get_raw_string(hawk, c, 0, tok) <= -1) return -1;
+			}
+	#if 0
+			
+			else if (c == '\'')
+			{
+				/* TODO: character literal when I add a character type?? */
+			}
+	#endif
+			else
+			{
+				unget_char (hawk, &hawk->sio.last);
+				hawk->sio.last = pc1;
+				c = pc1.c;
+				goto process_at_identifier;
+			}
+		}
 		else
 		{
+		process_at_identifier:
+			ADD_TOKEN_CHAR (hawk, tok, HAWK_T('@'));
+
 			/* expect normal identifier starting with an alphabet */
 			do 
 			{
@@ -6712,54 +6803,33 @@ retry:
 			}
 		}
 	}
-	else if (c == HAWK_T('B'))
-	{
-		GET_CHAR_TO (hawk, c);
-		if (c == HAWK_T('\"'))
-		{
-			/* multi-byte string/byte array */
-			SET_TOKEN_TYPE (hawk, tok, TOK_MBS);
-			if (get_string(hawk, c, HAWK_T('\\'), 0, 1, 0, tok) <= -1) return -1;
-		}
-		else if (c == HAWK_T('\''))
-		{
-			SET_TOKEN_TYPE (hawk, tok, TOK_MBS);
-			if (get_single_quoted_string(hawk, 1, tok) <= -1) return -1;
-		}
-		else
-		{
-			ADD_TOKEN_CHAR (hawk, tok, HAWK_T('B'));
-			goto process_identifier;
-		}
-	}
-	else if (c == HAWK_T('_') || hawk_is_ooch_alpha(c))
+	else if (c == '_' || hawk_is_ooch_alpha(c))
 	{
 		int type;
 
-	process_identifier:
 		/* identifier */
 		do 
 		{
 			ADD_TOKEN_CHAR (hawk, tok, c);
 			GET_CHAR_TO (hawk, c);
 		} 
-		while (c == HAWK_T('_') || hawk_is_ooch_alpha(c) || hawk_is_ooch_digit(c));
+		while (c == '_' || hawk_is_ooch_alpha(c) || hawk_is_ooch_digit(c));
 
 		type = classify_ident(hawk, HAWK_OOECS_OOCS(tok->name));
 		SET_TOKEN_TYPE (hawk, tok, type);
 	}
-	else if (c == HAWK_T('\"'))
+	else if (c == '\"')
 	{
 		/* double-quoted string */
 		SET_TOKEN_TYPE (hawk, tok, TOK_STR);
-		if (get_string(hawk, c, HAWK_T('\\'), 0, 0, 0, tok) <= -1) return -1;
+		if (get_string(hawk, c, '\\', 0, 0, 0, tok) <= -1) return -1;
 	}
-	else if (c == HAWK_T('\''))
+#if 0
+	else if (c == '\''))
 	{
-		/* single-quoted string - no escaping */
-		SET_TOKEN_TYPE (hawk, tok, TOK_STR);
-		if (get_single_quoted_string(hawk, 0, tok) <= -1) return -1;
+		/* TODO: character literal */
 	}
+#endif
 	else
 	{
 	try_get_symbols:
@@ -7025,9 +7095,9 @@ static int deparse (hawk_t* hawk)
 
 		hawk_getkwname (hawk, HAWK_KWID_BEGIN, &kw);
 
-		if (hawk_putsrcoochars (hawk, kw.ptr, kw.len) <= -1) EXIT_DEPARSE ();
-		if (hawk_putsrcoocstr (hawk, HAWK_T(" ")) <= -1) EXIT_DEPARSE ();
-		if (hawk_prnnde (hawk, nde) <= -1) EXIT_DEPARSE ();
+		if (hawk_putsrcoochars(hawk, kw.ptr, kw.len) <= -1) EXIT_DEPARSE ();
+		if (hawk_putsrcoocstr(hawk, HAWK_T(" ")) <= -1) EXIT_DEPARSE ();
+		if (hawk_prnnde(hawk, nde) <= -1) EXIT_DEPARSE ();
 
 		if (hawk->opt.trait & HAWK_CRLF)
 		{
@@ -7194,7 +7264,7 @@ static int flush_out (hawk_t* hawk)
 
 int hawk_putsrcoocstr (hawk_t* hawk, const hawk_ooch_t* str)
 {
-	while (*str != HAWK_T('\0'))
+	while (*str != '\0')
 	{
 		if (put_char(hawk, *str) <= -1) return -1;
 		str++;
diff --git a/hawk/lib/tree.c b/hawk/lib/tree.c
index 359614de..234e0f6b 100644
--- a/hawk/lib/tree.c
+++ b/hawk/lib/tree.c
@@ -423,7 +423,7 @@ static int print_expr (hawk_t* hawk, hawk_nde_t* nde)
 			hawk_bch_t* ptr;
 			hawk_oow_t len, i;
 
-			PUT_SRCSTR (hawk, HAWK_T("B\""));
+			PUT_SRCSTR (hawk, HAWK_T("@b\""));
 			ptr = ((hawk_nde_mbs_t*)nde)->ptr;
 			len = ((hawk_nde_mbs_t*)nde)->len;
 			for (i = 0; i < len; i++)
@@ -1143,9 +1143,9 @@ static int print_stmts (hawk_t* hawk, hawk_nde_t* tree, int depth)
 {
 	hawk_nde_t* p = tree;
 
-	while (p != HAWK_NULL) 
+	while (p) 
 	{
-		if (print_stmt (hawk, p, depth) == -1) return -1;
+		if (print_stmt(hawk, p, depth) == -1) return -1;
 		p = p->next;
 	}
 
@@ -1154,19 +1154,19 @@ static int print_stmts (hawk_t* hawk, hawk_nde_t* tree, int depth)
 
 int hawk_prnpt (hawk_t* hawk, hawk_nde_t* tree)
 {
-	return print_stmts (hawk, tree, 0);
+	return print_stmts(hawk, tree, 0);
 }
 
 int hawk_prnnde (hawk_t* hawk, hawk_nde_t* tree)
 {
-	return print_stmt (hawk, tree, 0);
+	return print_stmt(hawk, tree, 0);
 }
 
 int hawk_prnptnpt (hawk_t* hawk, hawk_nde_t* tree)
 {
 	hawk_nde_t* nde = tree;
 
-	while (nde != HAWK_NULL)
+	while (nde)
 	{
 		if (print_expr (hawk, nde) == -1) return -1;
 		if (nde->next == HAWK_NULL) break;
@@ -1183,7 +1183,7 @@ void hawk_clrpt (hawk_t* hawk, hawk_nde_t* tree)
 	hawk_nde_t* p = tree;
 	hawk_nde_t* next;
 
-	while (p != HAWK_NULL) 
+	while (p) 
 	{
 		next = p->next;
 
diff --git a/hawk/t/Makefile.am b/hawk/t/Makefile.am
index 945b9008..755546da 100644
--- a/hawk/t/Makefile.am
+++ b/hawk/t/Makefile.am
@@ -12,7 +12,7 @@ AM_CPPFLAGS = \
 AM_LDFLAGS = -L$(abs_builddir)/../lib  -L$(libdir)
 LDADD = $(PTHREAD_LIBS)
 
-check_SCRIPTS = h-001.hawk
+check_SCRIPTS = h-001.hawk h-002.hawk
 ##noinst_SCRIPTS = $(check_SCRIPTS)
 EXTRA_DIST = $(check_SCRIPTS)
 
diff --git a/hawk/t/Makefile.in b/hawk/t/Makefile.in
index 4005f0c6..0bbb5627 100644
--- a/hawk/t/Makefile.in
+++ b/hawk/t/Makefile.in
@@ -558,7 +558,7 @@ AM_CPPFLAGS = \
 
 AM_LDFLAGS = -L$(abs_builddir)/../lib  -L$(libdir)
 LDADD = $(PTHREAD_LIBS)
-check_SCRIPTS = h-001.hawk
+check_SCRIPTS = h-001.hawk h-002.hawk
 EXTRA_DIST = $(check_SCRIPTS)
 t_001_SOURCES = t-001.c t.h
 t_002_SOURCES = t-002.c t.h
diff --git a/hawk/t/ensure.inc b/hawk/t/ensure.inc
new file mode 100644
index 00000000..9d07a0df
--- /dev/null
+++ b/hawk/t/ensure.inc
@@ -0,0 +1,8 @@
+function ensure (a, b, desc, line)
+{
+	if (a != b) 
+	{
+		printf ("FAILURE[%d] %s\n", line, desc);
+		exit (-1);
+	}
+}
diff --git a/hawk/t/h-001.hawk b/hawk/t/h-001.hawk
index 0a657d7f..784fa41c 100644
--- a/hawk/t/h-001.hawk
+++ b/hawk/t/h-001.hawk
@@ -1,14 +1,6 @@
 @pragma entry main
 
-
-function ensure (a, b, desc, line)
-{
-	if (a != b) 
-	{
-		printf ("FAILURE[%d] %s\n", line, desc);
-		exit (-1);
-	}
-}
+@include "ensure.inc";
 
 function call_by_ref_1(&a, b, &c)
 {
diff --git a/hawk/t/h-002.hawk b/hawk/t/h-002.hawk
new file mode 100644
index 00000000..313429c1
--- /dev/null
+++ b/hawk/t/h-002.hawk
@@ -0,0 +1,87 @@
+@pragma entry main
+@pragma implicit off
+
+@include "ensure.inc";
+
+function main()
+{
+
+	## call by reference. change an argument to array in the callee
+	{
+		@local ini, foo1, foo2, foo3, foo4;
+	
+		test1(foo1); 
+		test2(foo2); 
+		test3(foo3); 
+		test4(foo4); 
+		ensure (hawk::typename(foo1), "map", @SCRIPTNAME, @SCRIPTLINE);
+		ensure (hawk::typename(foo2), "map", @SCRIPTNAME, @SCRIPTLINE);
+		ensure (hawk::typename(foo3), "nil", @SCRIPTNAME, @SCRIPTLINE);
+		ensure (hawk::typename(foo4), "nil", @SCRIPTNAME, @SCRIPTLINE);
+		ensure (foo1[1], 1, @SCRIPTNAME, @SCRIPTLINE);
+		ensure (foo2[1], 1, @SCRIPTNAME, @SCRIPTLINE);
+		ensure (foo3[1], ini, @SCRIPTNAME, @SCRIPTLINE);
+		ensure (foo4[1], ini, @SCRIPTNAME, @SCRIPTLINE);
+	}	
+
+	## gsub 
+	{
+		@local w, x, y, z, z1, z2;
+		x = y = "x\\y";
+		gsub(/\\\\/, "A", x);
+		gsub("\\\\", "A", y);
+		ensure (x, "x\\y", @SCRIPTNAME, @SCRIPTLINE);
+		ensure (y, "xAy", @SCRIPTNAME, @SCRIPTLINE);
+
+		x = y = "x\\\\y";
+		gsub(/\\\\/, "A", x);
+		gsub("\\\\", "A", y);
+		ensure (x, "xAy", @SCRIPTNAME, @SCRIPTLINE);
+		ensure (y, "xAAy", @SCRIPTNAME, @SCRIPTLINE);
+	}
+
+	## gsub - POSIX rule for &, \&, \\&, \\\& 
+	{	
+		@local w, x, y, z, z1, z2, z3;
+		w = x = y = z = z1 = z2 = "xax";
+
+       		gsub(/a/, "\&", w);  # gsub sees &
+       		gsub(/a/, "\\&", x);   # gsub sees \&
+       		gsub(/a/, "\\\&", y);   # gsub sees \&
+
+       		gsub(/a/, "\\\\&", z);  # gsub sees \\&
+       		gsub(/a/, "\\\\\&", z1); # gsub sees \\&
+       		gsub(/a/, "\\\\\\&", z2); # gsub sees \\\&
+
+		ensure (w, "xax", @SCRIPTNAME, @SCRIPTLINE);
+		ensure (x, "x&x", @SCRIPTNAME, @SCRIPTLINE);
+		ensure (y, "x&x", @SCRIPTNAME, @SCRIPTLINE);
+		ensure (z, "x\\ax", @SCRIPTNAME, @SCRIPTLINE);
+		ensure (z1, "x\\ax", @SCRIPTNAME, @SCRIPTLINE);
+		ensure (z2, "x\\&x", @SCRIPTNAME, @SCRIPTLINE);
+	}
+
+	## gsub - POSIX rule for &, \&, \\&, \\\&  - express the same test with a raw string literal
+	{	
+		@local w, x, y, z;
+		w = x = y = z = "xax";
+
+       		gsub(/a/, @r"&", w);  # gsub sees &
+       		gsub(/a/, @r"\&", x);   # gsub sees \&
+
+       		gsub(/a/, @r"\\&", y);  # gsub sees \\&
+       		gsub(/a/, @r"\\\&", z); # gsub sees \\\&
+
+		ensure (w, "xax", @SCRIPTNAME, @SCRIPTLINE);
+		ensure (x, "x&x", @SCRIPTNAME, @SCRIPTLINE);
+		ensure (y, @r"x\ax", @SCRIPTNAME, @SCRIPTLINE);
+		ensure (z, @r"x\&x", @SCRIPTNAME, @SCRIPTLINE);
+	}
+
+	print "SUCCESS";
+}
+
+function test1(&foo) { test2(foo) }
+function test2(&bar) { bar[1] = 1 }
+function test3(foo) { test2(foo) }
+function test4(bar) { bar[1] = 1 }