diff --git a/include/ps/internal/assign_op.h b/include/ps/internal/assign_op.h
index 834f523e..6f0a04ae 100644
--- a/include/ps/internal/assign_op.h
+++ b/include/ps/internal/assign_op.h
@@ -21,21 +21,21 @@ enum AssignOp {
 };
 
 /**
- * \brief return an assignment function: right op= left
+ * \brief return an assignment function: rhs op= lhs
  */
 template<typename T>
 inline void AssignFunc(const T& lhs, AssignOp op, T* rhs) {
   switch (op) {
     case ASSIGN:
-      *right = left; break;
+      *rhs = lhs; break;
     case PLUS:
-      *right += left; break;
+      *rhs += lhs; break;
     case MINUS:
-      *right -= left; break;
+      *rhs -= lhs; break;
     case TIMES:
-      *right *= left; break;
+      *rhs *= lhs; break;
     case DIVIDE:
-      *right /= left; break;
+      *rhs /= lhs; break;
     default:
       LOG(FATAL) << "use AssignOpInt..";
   }
@@ -49,21 +49,21 @@ template<typename T>
 inline void AssignFuncInt(const T& lhs, AssignOp op, T* rhs) {
   switch (op) {
     case ASSIGN:
-      *right = left; break;
+      *rhs = lhs; break;
     case PLUS:
-      *right += left; break;
+      *rhs += lhs; break;
     case MINUS:
-      *right -= left; break;
+      *rhs -= lhs; break;
     case TIMES:
-      *right *= left; break;
+      *rhs *= lhs; break;
     case DIVIDE:
-      *right /= left; break;
+      *rhs /= lhs; break;
     case AND:
-      *right &= left; break;
+      *rhs &= lhs; break;
     case OR:
-      *right |= left; break;
+      *rhs |= lhs; break;
     case XOR:
-      *right ^= left; break;
+      *rhs ^= lhs; break;
   }
 }
 
diff --git a/include/ps/internal/parallel_kv_match.h b/include/ps/internal/parallel_kv_match.h
index bf5ab0b7..fb719b88 100644
--- a/include/ps/internal/parallel_kv_match.h
+++ b/include/ps/internal/parallel_kv_match.h
@@ -30,7 +30,7 @@ template <typename K, typename V>
 void ParallelOrderedMatch(
     const K* src_key, const K* src_key_end, const V* src_val,
     const K* dst_key, const K* dst_key_end, V* dst_val,
-    int k, AsOp op, size_t grainsize, size_t* n) {
+    int k, AssignOp op, size_t grainsize, size_t* n) {
   size_t src_len = std::distance(src_key, src_key_end);
   size_t dst_len = std::distance(dst_key, dst_key_end);
   if (dst_len == 0 || src_len == 0) return;
@@ -46,7 +46,7 @@ void ParallelOrderedMatch(
       } else {
         if (!(*dst_key < *src_key)) {
           for (int i = 0; i < k; ++i) {
-            AssignOp(dst_val[i], src_val[i], op);
+            AssignFunc(dst_val[i], src_val[i], op);
           }
           ++src_key; src_val += k;
           *n += k;
diff --git a/src/van.cc b/src/van.cc
index 44b07b3f..129e020f 100644
--- a/src/van.cc
+++ b/src/van.cc
@@ -18,7 +18,7 @@ namespace ps {
 // don't send heartbeast in default. because if the scheduler received a
 // heartbeart signal from a node before connected to that node, then it could be
 // problem.
-const static int kDefaultHeartbeatInterval = 0;
+static const int kDefaultHeartbeatInterval = 0;
 
 Van* Van::Create(const std::string& type) {
   if (type == "zmq") {
@@ -140,7 +140,8 @@ int Van::Send(const Message& msg) {
 
 void Van::Receiving() {
   const char* heartbeat_timeout_val = Environment::Get()->find("PS_HEARTBEAT_TIMEOUT");
-  const int heartbeat_timeout = heartbeat_timeout_val ? atoi(heartbeat_timeout_val) : kDefaultHeartbeatInterval;
+  const int heartbeat_timeout = heartbeat_timeout_val ? atoi(heartbeat_timeout_val)
+                                                      : kDefaultHeartbeatInterval;
   Meta nodes;  // for scheduler usage
   while (true) {
     Message msg;