diff --git a/lib/hcl-prv.h b/lib/hcl-prv.h
index 7c08cce..78bb7b3 100644
--- a/lib/hcl-prv.h
+++ b/lib/hcl-prv.h
@@ -178,6 +178,7 @@ enum hcl_tok_type_t
 	HCL_TOK_SELF,
 	HCL_TOK_SUPER,
 
+	HCL_TOK_BINOP,
 	HCL_TOK_IDENT,
 	HCL_TOK_IDENT_DOTTED,
 	HCL_TOK_IDENT_DOTTED_CLA,
@@ -628,6 +629,12 @@ struct hcl_flx_pi_t
 	int is_cla; /* class-level accrssor. prefixed with self/super */
 };
 
+typedef struct hcl_flx_binop_t hcl_flx_binop_t;
+struct hcl_flx_binop_t
+{
+	hcl_oow_t _not_used;
+};
+
 typedef struct hcl_flx_pn_t hcl_flx_pn_t;
 struct hcl_flx_pn_t
 {
@@ -685,6 +692,7 @@ enum hcl_flx_state_t
 	HCL_FLX_HMARKED_IDENT,  /* hash-marked identifier like #include, etc */
 	HCL_FLX_HMARKED_NUMBER, /* hash-marked number - radixed number like #xABCD */
 	HCL_FLX_PLAIN_IDENT,    /* plain identifier */
+	HCL_FLX_BINOP,          /* binary operator */
 	HCL_FLX_PLAIN_NUMBER,   /* plain number */
 	HCL_FLX_QUOTED_TOKEN,   /* string, character */
 	HCL_FLX_SIGNED_TOKEN,   /* prefixed with + or - */
@@ -776,6 +784,7 @@ struct hcl_compiler_t
 				hcl_flx_hb_t hb; /* #b ... */
 				hcl_flx_hn_t hn; /* hash-marked number - radixed number */
 				hcl_flx_pi_t pi; /* plain identifier */
+				hcl_flx_binop_t binop; /* binary operator */
 				hcl_flx_pn_t pn; /* plain number */
 				hcl_flx_qt_t qt; /* quoted token */
 				hcl_flx_st_t st; /* signed token */
diff --git a/lib/read.c b/lib/read.c
index 328dfa5..4a147c2 100644
--- a/lib/read.c
+++ b/lib/read.c
@@ -181,12 +181,6 @@ static HCL_INLINE int is_linebreak (hcl_ooci_t c)
 	return c == '\n'; /* make sure this is one of the space chars in is_spacechar() */
 }
 
-static HCL_INLINE int is_alphachar (hcl_ooci_t c)
-{
-/* TODO: support full unicode */
-	return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z');
-}
-
 static HCL_INLINE int is_digitchar (hcl_ooci_t c)
 {
 /* TODO: support full unicode */
@@ -199,11 +193,20 @@ static HCL_INLINE int is_xdigitchar (hcl_ooci_t c)
 	return (c >= '0' && c <= '9') || (c >= 'A' && c <= 'F') || (c >= 'a' && c <= 'f');
 }
 
+#if 0
+static HCL_INLINE int is_alphachar (hcl_ooci_t c)
+{
+/* TODO: support full unicode */
+	return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z');
+}
+
+
 static HCL_INLINE int is_alnumchar (hcl_ooci_t c)
 {
 /* TODO: support full unicode */
 	return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9');
 }
+#endif
 
 static HCL_INLINE int is_delimchar (hcl_ooci_t c)
 {
@@ -213,6 +216,12 @@ static HCL_INLINE int is_delimchar (hcl_ooci_t c)
 	       c == '#' || c == '\"' || c == '\'' || c == '\\' || is_spacechar(c) || c == HCL_OOCI_EOF;
 }
 
+static HCL_INLINE int is_binopchar (hcl_ooci_t c)
+{
+	return c == '&' || c == '*' || c == '+' || c == '-' || c == '/' || c == '%' ||
+	       c == '<' || c == '>' || c == '=' || c == '@' || c == '|' || c == '~';
+}
+
 /* TODO: remove this use the one in comp.c */
 static int copy_string_to (hcl_t* hcl, const hcl_oocs_t* src, hcl_oocs_t* dst, hcl_oow_t* dst_capa, int append, hcl_ooch_t add_delim)
 {
@@ -1526,6 +1535,7 @@ static int feed_process_token (hcl_t* hcl)
 			frd->obj = hcl_makecnodebstrlit(hcl, 0, TOKEN_LOC(hcl), TOKEN_NAME(hcl));
 			goto auto_xlist;
 
+		case HCL_TOK_BINOP: /* TODO: handle this specially as a binary operator */
 		case HCL_TOK_IDENT:
 			frd->obj = hcl_makecnodesymbol(hcl, 0, TOKEN_LOC(hcl), TOKEN_NAME(hcl));
 			goto auto_xlist;
@@ -1747,6 +1757,7 @@ static int feed_continue_with_char (hcl_t* hcl, hcl_ooci_t c, hcl_flx_state_t st
 #define FLX_HB(hcl) (&((hcl)->c->feed.lx.u.hb))
 #define FLX_HN(hcl) (&((hcl)->c->feed.lx.u.hn))
 #define FLX_PI(hcl) (&((hcl)->c->feed.lx.u.pi))
+#define FLX_BINOP(hcl) (&((hcl)->c->feed.lx.u.binop))
 #define FLX_PN(hcl) (&((hcl)->c->feed.lx.u.pn))
 #define FLX_QT(hcl) (&((hcl)->c->feed.lx.u.qt))
 #define FLX_ST(hcl) (&((hcl)->c->feed.lx.u.st))
@@ -1793,6 +1804,11 @@ static HCL_INLINE void init_flx_pi (hcl_flx_pi_t* pi)
 	HCL_MEMSET (pi, 0, HCL_SIZEOF(*pi));
 }
 
+static HCL_INLINE void init_flx_binop (hcl_flx_binop_t* binop)
+{
+	HCL_MEMSET (binop, 0, HCL_SIZEOF(*binop));
+}
+
 static HCL_INLINE void init_flx_pn (hcl_flx_pn_t* pn)
 {
 	HCL_MEMSET (pn, 0, HCL_SIZEOF(*pn));
@@ -1906,9 +1922,16 @@ static int flx_start (hcl_t* hcl, hcl_ooci_t c)
 			goto consumed;
 
 		default:
-		/* TODO: limit the identifier characters and cause syntax error for other characters.. */
-			init_flx_pi (FLX_PI(hcl));
-			FEED_CONTINUE (hcl, HCL_FLX_PLAIN_IDENT);
+			if (is_binopchar(c))
+			{
+				init_flx_binop (FLX_BINOP(hcl));
+				FEED_CONTINUE (hcl, HCL_FLX_BINOP);
+			}
+			else
+			{
+				init_flx_pi (FLX_PI(hcl));
+				FEED_CONTINUE (hcl, HCL_FLX_PLAIN_IDENT);
+			}
 			goto not_consumed;
 	}
 
@@ -2377,6 +2400,28 @@ not_consumed:
 	return 0;
 }
 
+static int flx_binop (hcl_t* hcl, hcl_ooci_t c) /* identifier */
+{
+	hcl_flx_binop_t* binop = FLX_BINOP(hcl);
+
+	if (is_binopchar(c))
+	{
+		ADD_TOKEN_CHAR (hcl, c);
+		goto consumed;
+	}
+	else
+	{
+		FEED_WRAP_UP (hcl, HCL_TOK_BINOP);
+		goto not_consumed;
+	}
+
+consumed:
+	return 1;
+
+not_consumed:
+	return 0;
+}
+
 static int flx_plain_number (hcl_t* hcl, hcl_ooci_t c) /* number */
 {
 	hcl_flx_pn_t* pn = FLX_PN(hcl);
@@ -2729,6 +2774,7 @@ static int feed_char (hcl_t* hcl, hcl_ooci_t c)
 		case HCL_FLX_HMARKED_IDENT:    return flx_hmarked_ident(hcl, c);
 		case HCL_FLX_HMARKED_NUMBER:   return flx_hmarked_number(hcl, c);
 		case HCL_FLX_PLAIN_IDENT:      return flx_plain_ident(hcl, c);
+		case HCL_FLX_BINOP:            return flx_binop(hcl, c);
 		case HCL_FLX_PLAIN_NUMBER:     return flx_plain_number(hcl, c);
 		case HCL_FLX_QUOTED_TOKEN:     return flx_quoted_token(hcl, c);
 		case HCL_FLX_SIGNED_TOKEN:     return flx_signed_token(hcl, c);
diff --git a/t/Makefile.am b/t/Makefile.am
index ad8bd46..f3ac5bc 100644
--- a/t/Makefile.am
+++ b/t/Makefile.am
@@ -22,6 +22,8 @@ check_ERRORS = \
 	feed-5005.err \
 	feed-5006.err \
 	feed-5007.err \
+	feed-5008.err \
+	feed-5009.err \
 	mlist-5001.err \
 	var-5001.err \
 	var-5002.err \
diff --git a/t/Makefile.in b/t/Makefile.in
index 8f25d3c..9145492 100644
--- a/t/Makefile.in
+++ b/t/Makefile.in
@@ -493,6 +493,8 @@ check_ERRORS = \
 	feed-5005.err \
 	feed-5006.err \
 	feed-5007.err \
+	feed-5008.err \
+	feed-5009.err \
 	mlist-5001.err \
 	var-5001.err \
 	var-5002.err \
diff --git a/t/feed-5008.err b/t/feed-5008.err
new file mode 100644
index 0000000..7070959
--- /dev/null
+++ b/t/feed-5008.err
@@ -0,0 +1,3 @@
+defun :: fun1() { ##ERROR: syntax error - function name not symbol in defun
+	return 10;
+};
diff --git a/t/feed-5009.err b/t/feed-5009.err
new file mode 100644
index 0000000..b745f7e
--- /dev/null
+++ b/t/feed-5009.err
@@ -0,0 +1,3 @@
+defun :* fun1() { ##ERROR: syntax error - function name not symbol in defun
+	return 10;
+};