diff --git a/lib/comp.c b/lib/comp.c
index e386be8..038297e 100644
--- a/lib/comp.c
+++ b/lib/comp.c
@@ -552,7 +552,8 @@ static int emit_single_param_instruction (hcl_t* hcl, int cmd, hcl_oow_t param_1
 		case HCL_CODE_STORE_INTO_CLSVAR_M_X:
 		case HCL_CODE_POP_INTO_CLSVAR_M_X:
 
-		case HCL_CODE_CLASS_MSTORE:
+		case HCL_CODE_CLASS_CMSTORE:
+		case HCL_CODE_CLASS_IMSTORE:
 		case HCL_CODE_TRY_ENTER:
 		case HCL_CODE_TRY_ENTER2:
 		case HCL_CODE_PUSH_INTLIT:
@@ -1279,7 +1280,8 @@ enum
 	COP_EMIT_POP_STACKTOP,
 	COP_EMIT_RETURN,
 	COP_EMIT_SET,
-	COP_EMIT_CLASS_MSTORE,
+	COP_EMIT_CLASS_CMSTORE,
+	COP_EMIT_CLASS_IMSTORE,
 	COP_EMIT_THROW,
 
 	COP_POST_IF_COND,
@@ -4803,7 +4805,16 @@ static HCL_INLINE int post_lambda (hcl_t* hcl)
 			if (x == 0)
 			{
 				/* arrange to save to the method slot */
-				SWITCH_TOP_CFRAME (hcl, COP_EMIT_CLASS_MSTORE, defun_name);
+				if (xxxx)
+				{
+					/* class method */
+					SWITCH_TOP_CFRAME (hcl, COP_EMIT_CLASS_CMSTORE, defun_name);
+				}
+				else
+				{
+					/* instance method */
+					SWITCH_TOP_CFRAME (hcl, COP_EMIT_CLASS_IMSTORE, defun_name);
+				}
 				cf = GET_TOP_CFRAME(hcl);
 			}
 			else
@@ -4910,20 +4921,39 @@ static HCL_INLINE int emit_set (hcl_t* hcl)
 	return 0;
 }
 
-static HCL_INLINE int emit_class_mstore (hcl_t* hcl)
+static HCL_INLINE int emit_class_cmstore (hcl_t* hcl)
 {
 	hcl_cframe_t* cf;
 	hcl_oop_t lit;
 	hcl_oow_t index;
 
 	cf = GET_TOP_CFRAME(hcl);
-	HCL_ASSERT (hcl, cf->opcode == COP_EMIT_CLASS_MSTORE);
+	HCL_ASSERT (hcl, cf->opcode == COP_EMIT_CLASS_CMSTORE);
 
 	lit = hcl_makesymbol(hcl, HCL_CNODE_GET_TOKPTR(cf->operand), HCL_CNODE_GET_TOKLEN(cf->operand));
 	if (HCL_UNLIKELY(!lit)) return -1;
 
 	if (add_literal(hcl, lit, &index) <= -1) return -1;
-	if (emit_single_param_instruction(hcl,  HCL_CODE_CLASS_MSTORE, index, HCL_CNODE_GET_LOC(cf->operand)) <= -1) return -1;
+	if (emit_single_param_instruction(hcl,  HCL_CODE_CLASS_CMSTORE, index, HCL_CNODE_GET_LOC(cf->operand)) <= -1) return -1;
+
+	POP_CFRAME (hcl);
+	return 0;
+}
+
+static HCL_INLINE int emit_class_imstore (hcl_t* hcl)
+{
+	hcl_cframe_t* cf;
+	hcl_oop_t lit;
+	hcl_oow_t index;
+
+	cf = GET_TOP_CFRAME(hcl);
+	HCL_ASSERT (hcl, cf->opcode == COP_EMIT_CLASS_IMSTORE);
+
+	lit = hcl_makesymbol(hcl, HCL_CNODE_GET_TOKPTR(cf->operand), HCL_CNODE_GET_TOKLEN(cf->operand));
+	if (HCL_UNLIKELY(!lit)) return -1;
+
+	if (add_literal(hcl, lit, &index) <= -1) return -1;
+	if (emit_single_param_instruction(hcl,  HCL_CODE_CLASS_IMSTORE, index, HCL_CNODE_GET_LOC(cf->operand)) <= -1) return -1;
 
 	POP_CFRAME (hcl);
 	return 0;
@@ -5176,8 +5206,12 @@ int hcl_compile (hcl_t* hcl, hcl_cnode_t* obj, int flags)
 				if (emit_set(hcl) <= -1) goto oops;
 				break;
 
-			case COP_EMIT_CLASS_MSTORE:
-				if (emit_class_mstore(hcl) <= -1) goto oops;
+			case COP_EMIT_CLASS_CMSTORE:
+				if (emit_class_cmstore(hcl) <= -1) goto oops;
+				break;
+
+			case COP_EMIT_CLASS_IMSTORE:
+				if (emit_class_imstore(hcl) <= -1) goto oops;
 				break;
 
 			case COP_EMIT_THROW:
diff --git a/lib/decode.c b/lib/decode.c
index a003d2c..193be32 100644
--- a/lib/decode.c
+++ b/lib/decode.c
@@ -386,9 +386,14 @@ int hcl_decode (hcl_t* hcl, hcl_oow_t start, hcl_oow_t end)
 				LOG_INST_0 (hcl, "class_pexit");
 				break;
 
-			case HCL_CODE_CLASS_MSTORE:
+			case HCL_CODE_CLASS_CMSTORE:
 				FETCH_PARAM_CODE_TO (hcl, b1);
-				LOG_INST_1 (hcl, "class_mstore %zu", b1);
+				LOG_INST_1 (hcl, "class_cmstore %zu", b1);
+				break;
+
+			case HCL_CODE_CLASS_IMSTORE:
+				FETCH_PARAM_CODE_TO (hcl, b1);
+				LOG_INST_1 (hcl, "class_imstore %zu", b1);
 				break;
 			/* -------------------------------------------------------- */
 
diff --git a/lib/exec.c b/lib/exec.c
index c866c0a..4ad0aba 100644
--- a/lib/exec.c
+++ b/lib/exec.c
@@ -3594,13 +3594,44 @@ if (do_throw(hcl, hcl->_nil, fetched_instruction_pointer) <= -1)
 				break;
 			}
 
-			case HCL_CODE_CLASS_MSTORE:
+			case HCL_CODE_CLASS_CMSTORE:
+			{
+/* TODO: change this part */
+				hcl_oop_t class_;
+				hcl_oop_t dic;
+
+				FETCH_PARAM_CODE_TO (hcl, b1);
+				LOG_INST_1 (hcl, "class_cmstore %zu", b1);
+
+				/* store the stack top in the member dictionary of the currect class with the key indicated by 'b1' */
+
+				HCL_ASSERT (hcl, !HCL_CLSTACK_IS_EMPTY(hcl));
+
+				HCL_CLSTACK_FETCH_TOP_TO (hcl, class_);
+				HCL_ASSERT (hcl, HCL_IS_CLASS(hcl, class_));
+
+				dic = ((hcl_oop_class_t)class_)->memdic;
+				HCL_ASSERT (hcl, HCL_IS_NIL(hcl, dic) || HCL_IS_DIC(hcl, dic));
+				if (HCL_IS_NIL(hcl, dic))
+				{
+					hcl_pushvolat (hcl, (hcl_oop_t*)&class_);
+					dic = hcl_makedic(hcl, 16); /* TODO: configurable initial size? */
+					hcl_popvolat (hcl);
+					if (HCL_UNLIKELY(!dic))  goto oops_with_errmsg_supplement;
+					((hcl_oop_class_t)class_)->memdic = dic;
+				}
+
+				if (!hcl_putatdic(hcl, (hcl_oop_dic_t)dic, hcl->active_function->literal_frame[b1], HCL_STACK_GETTOP(hcl))) goto oops_with_errmsg_supplement;
+				break;
+			}
+
+			case HCL_CODE_CLASS_IMSTORE:
 			{
 				hcl_oop_t class_;
 				hcl_oop_t dic;
 
 				FETCH_PARAM_CODE_TO (hcl, b1);
-				LOG_INST_1 (hcl, "class_mstore %zu", b1);
+				LOG_INST_1 (hcl, "class_imstore %zu", b1);
 
 				/* store the stack top in the member dictionary of the currect class with the key indicated by 'b1' */
 
diff --git a/lib/hcl-prv.h b/lib/hcl-prv.h
index 952ccdf..12ae38a 100644
--- a/lib/hcl-prv.h
+++ b/lib/hcl-prv.h
@@ -930,8 +930,9 @@ enum hcl_bcode_t
 	HCL_CODE_CLASS_PEXIT              = 0xE3, /* 227 */
 
 	HCL_CODE_PUSH_OBJVAR_X            = 0xE4, /* 228 ## */
-	HCL_CODE_CLASS_MSTORE             = 0xE5, /* 229 */
-	/* UNUSED - 0xE6 - 0xE7 */
+	HCL_CODE_CLASS_CMSTORE            = 0xE5, /* 229 */
+	HCL_CODE_CLASS_IMSTORE            = 0xE6, /* 230 */
+	/* UNUSED - 0xE7 */
 
 	HCL_CODE_STORE_INTO_OBJVAR_X      = 0xE8, /* 232 ## */
 	HCL_CODE_MAKE_ARRAY               = 0xE9, /* 233 ## */