diff --git a/lib/read.c b/lib/read.c
index 97a10e3..fc6cd52 100644
--- a/lib/read.c
+++ b/lib/read.c
@@ -120,10 +120,12 @@ enum list_flag_t
 {
 	QUOTED       = (1 << 0),
 	DOTTED       = (1 << 1),
+
 	COMMAED      = (1 << 2),
 	COLONED      = (1 << 3),
 	COLONEQED    = (1 << 4),
 	BINOPED      = (1 << 5),
+
 	CLOSED       = (1 << 6),
 	JSON         = (1 << 7),
 	DATA_LIST    = (1 << 8),
@@ -594,7 +596,7 @@ static HCL_INLINE hcl_cnode_t* leave_list (hcl_t* hcl, hcl_loc_t* list_loc, int*
 		/* HACK */
 		if (concode == HCL_CONCODE_ALIST)
 		{
-			/* tranform (var := val) to (set var val) */
+			/* tranform (var := val) to (set var val) - note ALIST doesn't contain the := symbol */
 			hcl_cnode_t* sym, * newhead, * lval;
 			hcl_oocs_t fake_tok, * fake_tok_ptr = HCL_NULL;
 
@@ -637,7 +639,6 @@ static HCL_INLINE hcl_cnode_t* leave_list (hcl_t* hcl, hcl_loc_t* list_loc, int*
 				fake_tok_ptr = &fake_tok;
 			}
 
-
 			HCL_ASSERT (hcl, count >= 2); /* the missing rvalue check has been done above */
 			if (count != 2)
 			{
@@ -660,7 +661,6 @@ static HCL_INLINE hcl_cnode_t* leave_list (hcl_t* hcl, hcl_loc_t* list_loc, int*
 				return HCL_NULL;
 			}
 
-
 			/* create a new head joined with set or set-r */
 			newhead = hcl_makecnodecons(hcl, 0, &loc, fake_tok_ptr, sym, head);
 			if (HCL_UNLIKELY(!newhead))
@@ -675,6 +675,36 @@ static HCL_INLINE hcl_cnode_t* leave_list (hcl_t* hcl, hcl_loc_t* list_loc, int*
 			head = newhead;
 			concode = HCL_CONCODE_XLIST; /* switch back to XLIST */
 		}
+		else if (concode == HCL_CONCODE_BLIST)
+		{
+			/* x binop y -> binop x y - BLIST contains BINOP in it */
+			hcl_cnode_t* x, * binop;
+
+			x = HCL_CNODE_CONS_CAR(head);
+			if (x && HCL_CNODE_IS_ELIST(x))
+			{
+				hcl_setsynerr (hcl, HCL_SYNERR_LVALUE, HCL_CNODE_GET_LOC(x), HCL_CNODE_GET_TOK(x));
+				if (head) hcl_freecnode (hcl, head);
+				return HCL_NULL;
+			}
+
+			/* swap x and binop */
+			binop = HCL_CNODE_CONS_CDR(head);
+			if (!binop || !HCL_CNODE_IS_CONS(binop) || !HCL_CNODE_CONS_CDR(binop) || !HCL_CNODE_IS_CONS(HCL_CNODE_CONS_CDR(binop)))
+			{
+				hcl_setsynerrbfmt (hcl, HCL_SYNERR_NOVALUE, HCL_CNODE_GET_LOC(x), HCL_CNODE_GET_TOK(x), "no operand after binary operator");
+				if (head) hcl_freecnode (hcl, head);
+				return HCL_NULL;
+			}
+
+/* TODO: support multiple operators and operands .. like 1 + 2 - 3.. -> currently can_binop_list() disallows more operators */
+			HCL_ASSERT (hcl, count == 3);
+
+			HCL_CNODE_CONS_CDR(head) = HCL_CNODE_CONS_CDR(binop);
+			HCL_CNODE_CONS_CDR(binop) = head;
+			head = binop;
+			concode = HCL_CONCODE_XLIST;
+		}
 		/* END HACK */
 
 		HCL_CNODE_CONS_CONCODE(head) = concode;
@@ -1339,7 +1369,7 @@ static int feed_process_token (hcl_t* hcl)
 			int can = 0;
 			if (frd->level <= 0 || !(can = can_binop_list(hcl)))
 			{
-				hcl_setsynerr (hcl, HCL_SYNERR_BANNED, TOKEN_LOC(hcl), HCL_NULL);
+				hcl_setsynerrbfmt (hcl, HCL_SYNERR_BANNED, TOKEN_LOC(hcl), TOKEN_NAME(hcl), "prohibited binary operator");
 				goto oops;
 			}
 			if (can == 1) goto ident; /* if binop is the first in the list */
diff --git a/t/feed-5001.err b/t/feed-5001.err
index 071df03..6d70e01 100644
--- a/t/feed-5001.err
+++ b/t/feed-5001.err
@@ -1,3 +1,22 @@
+##
+
+x := (+ 10 20) "aaaa"; ##ERROR: syntax error - too many rvalues
+
+---
+
+##
+
+x := (10 +); ##ERROR: syntax error - no operand after binary operator
+
+---
+
+##
+
+x := (10 + 20 * 4); ##ERROR: syntax error - prohibited binary operator
+
+---
+
+
 ## you can't have another colon before the method..
 (obj: :method) ##ERROR: syntax error - : disallowed
 
diff --git a/t/insta-01.hcl b/t/insta-01.hcl
index 4e6f874..7e7e3ac 100644
--- a/t/insta-01.hcl
+++ b/t/insta-01.hcl
@@ -34,24 +34,24 @@ defclass B :: A | d e f | {
 };
 
 a := ((B:newInstance 1 2 3):sum);
-if (/= a 18) { printf "ERROR: a must be 18\n"; } \
+if (a /= 18) { printf "ERROR: a must be 18\n"; } \
 else { printf "OK %d\n" a; };
 
 b := (B:newInstance 2 3 4);
 a := (b:get-a);
-if (/= a 4) {printf "ERROR: a must be 4\n" } \
+if (a /= 4) {printf "ERROR: a must be 4\n" } \
 else { printf "OK %d\n" a };
 
 a := (b:get-b);
-if (/= a 6) { printf "ERROR: a must be 6\n" } \
+if (a /= 6) { printf "ERROR: a must be 6\n" } \
 else { printf "OK %d\n" a };
 
 a := (b:get-c);
-if (/= a 8) { printf "ERROR: a must be 8\n" } \
+if (a /= 8) { printf "ERROR: a must be 8\n" } \
 else {printf "OK %d\n" a };
 
 a := (b:sum);
-if (/= a 27) { printf "ERROR: a must be 27\n" } \
+if (a /= 27) { printf "ERROR: a must be 27\n" } \
 else { printf "OK %d\n" a };
 
 ## super is equivalent to self unless a message is sent to it.