diff --git a/src/lua_gears.cc b/src/lua_gears.cc
index beb0fdc..54de4ba 100644
--- a/src/lua_gears.cc
+++ b/src/lua_gears.cc
@@ -3,6 +3,9 @@
 
 namespace rime {
 
+std::ostream &operator<<(std::ostream &os, const LuaErr &e) {
+  return os << " error(" << e.status << "): " << e.e;
+}
 //--- LuaTranslation
 bool LuaTranslation::Next() {
   if (exhausted()) {
@@ -11,8 +14,8 @@ bool LuaTranslation::Next() {
   auto r = lua_->resume<an<Candidate>>(f_);
   if (!r.ok()) {
     LuaErr e = r.get_err();
-    if (e.e != "")
-      LOG(ERROR) << "LuaTranslation::Next error(" << e.status << "): " << e.e;
+    LOG_IF(ERROR, e.e != "" ) << typeid(*this).name() <<"::" << __FUNCTION__
+                              << "[" << name_space_ << "]" << e;
     set_exhausted(true);
     return false;
   } else {
@@ -70,7 +73,7 @@ static void raw_init(lua_State *L, const Ticket &t,
       *fini = LuaObj::todata(L, -1);
     }
     lua_pop(L, 1);
-    
+
     if (tags_match) {
       lua_getfield(L, -1, "tags_match");
       if (lua_type(L, -1) == LUA_TFUNCTION) {
@@ -92,6 +95,14 @@ static void raw_init(lua_State *L, const Ticket &t,
   *func = LuaObj::todata(L, -1);
   lua_pop(L, 1);
 }
+#define VOID_CALL(func, fname)                                                      \
+do {                                                                                \
+  if (func) {                                                                       \
+    auto r = lua_->void_call<an<LuaObj>, an<LuaObj>>(fini_, env_);                  \
+    LOG_IF(ERROR, !r.ok()) << typeid(*this).name() <<"::" << __FUNCTION__           \
+                           << "[" << name_space_ << ": " #fname "]" << r.get_err(); \
+  }                                                                                 \
+} while(0)
 
 //--- LuaFilter
 LuaFilter::LuaFilter(const Ticket& ticket, Lua* lua)
@@ -99,22 +110,24 @@ LuaFilter::LuaFilter(const Ticket& ticket, Lua* lua)
   lua->to_state([&](lua_State *L) {raw_init(L, ticket, &env_, &func_, &fini_, &tags_match_);});
 }
 
+bool LuaFilter::AppliesToSegment(Segment* segment) {
+  if ( ! tags_match_ )
+    return TagsMatch(segment);
+
+  auto r = lua_->call<bool, an<LuaObj>, Segment *, an<LuaObj>>(tags_match_, segment,  env_);
+  LOG_IF(ERROR, !r.ok()) << typeid(*this).name() << "::" << __FUNCTION__
+                         << "[" << name_space_ << "]" << r.get_err();
+  return (r.ok()) ? r.get() : false;
+}
+
 an<Translation> LuaFilter::Apply(
   an<Translation> translation, CandidateList* candidates) {
   auto f = lua_->newthread<an<LuaObj>, an<Translation>,
                            an<LuaObj>, CandidateList *>(func_, translation, env_, candidates);
-  return New<LuaTranslation>(lua_, f);
+  return New<LuaTranslation>(lua_, f, name_space_ + ":\"func\"");
 }
 
-LuaFilter::~LuaFilter() {
-  if (fini_) {
-    auto r = lua_->void_call<an<LuaObj>, an<LuaObj>>(fini_, env_);
-    if (!r.ok()) {
-      auto e = r.get_err();
-      LOG(ERROR) << "LuaFilter::~LuaFilter of "<< name_space_ << " error(" << e.status << "): " << e.e;
-    }
-  }
-}
+LuaFilter::~LuaFilter() { VOID_CALL(fini_, "fini"); }
 
 //--- LuaTranslator
 LuaTranslator::LuaTranslator(const Ticket& ticket, Lua* lua)
@@ -126,22 +139,14 @@ an<Translation> LuaTranslator::Query(const string& input,
                                      const Segment& segment) {
   auto f = lua_->newthread<an<LuaObj>, const string &, const Segment &,
                            an<LuaObj>>(func_, input, segment, env_);
-  an<Translation> t = New<LuaTranslation>(lua_, f);
+  an<Translation> t = New<LuaTranslation>(lua_, f, name_space_ + ": \"func\"");
   if (t->exhausted())
     return an<Translation>();
   else
     return t;
 }
 
-LuaTranslator::~LuaTranslator() {
-  if (fini_) {
-    auto r = lua_->void_call<an<LuaObj>, an<LuaObj>>(fini_, env_);
-    if (!r.ok()) {
-      auto e = r.get_err();
-      LOG(ERROR) << "LuaTranslator::~LuaTranslator of "<< name_space_ << " error(" << e.status << "): " << e.e;
-    }
-  }
-}
+LuaTranslator::~LuaTranslator() { VOID_CALL(fini_, "fini"); }
 
 //--- LuaSegmentor
 LuaSegmentor::LuaSegmentor(const Ticket& ticket, Lua *lua)
@@ -152,23 +157,12 @@ LuaSegmentor::LuaSegmentor(const Ticket& ticket, Lua *lua)
 bool LuaSegmentor::Proceed(Segmentation* segmentation) {
   auto r = lua_->call<bool, an<LuaObj>, Segmentation &,
                       an<LuaObj>>(func_, *segmentation, env_);
-  if (!r.ok()) {
-    auto e = r.get_err();
-    LOG(ERROR) << "LuaSegmentor::Proceed of "<< name_space_ << " error(" << e.status << "): " << e.e;
-    return true;
-  } else
-    return r.get();
+  LOG_IF(ERROR, !r.ok()) << typeid(*this).name() << "::" << __FUNCTION__
+                         << "[" << name_space_ << "]" << r.get_err();
+  return (r.ok()) ? r.get() : true ;
 }
 
-LuaSegmentor::~LuaSegmentor() {
-  if (fini_) {
-    auto r = lua_->void_call<an<LuaObj>, an<LuaObj>>(fini_, env_);
-    if (!r.ok()) {
-      auto e = r.get_err();
-      LOG(ERROR) << "LuaSegmentor::~LuaSegmentor of "<< name_space_ << " error(" << e.status << "): " << e.e;
-    }
-  }
-}
+LuaSegmentor::~LuaSegmentor() { VOID_CALL(fini_, "fini"); }
 
 //--- LuaProcessor
 LuaProcessor::LuaProcessor(const Ticket& ticket, Lua* lua)
@@ -180,8 +174,8 @@ ProcessResult LuaProcessor::ProcessKeyEvent(const KeyEvent& key_event) {
   auto r = lua_->call<int, an<LuaObj>, const KeyEvent&,
                       an<LuaObj>>(func_, key_event, env_);
   if (!r.ok()) {
-    auto e = r.get_err();
-    LOG(ERROR) << "LuaProcessor::ProcessKeyEvent of "<< name_space_ << " error(" << e.status << "): " << e.e;
+    LOG_IF(ERROR, !r.ok()) << typeid(*this).name() << "::" << __FUNCTION__
+                           << "[" << name_space_ << "]" << r.get_err();
     return kNoop;
   } else
     switch (r.get()) {
@@ -191,14 +185,6 @@ ProcessResult LuaProcessor::ProcessKeyEvent(const KeyEvent& key_event) {
     }
 }
 
-LuaProcessor::~LuaProcessor() {
-  if (fini_) {
-    auto r = lua_->void_call<an<LuaObj>, an<LuaObj>>(fini_, env_);
-    if (!r.ok()) {
-      auto e = r.get_err();
-      LOG(ERROR) << "LuaProcessor::~LuaProcessor of "<< name_space_ << " error(" << e.status << "): " << e.e;
-    }
-  }
-}
+LuaProcessor::~LuaProcessor() { VOID_CALL(fini_, "fini"); }
 
 }  // namespace rime
diff --git a/src/lua_gears.h b/src/lua_gears.h
index d763970..8774f19 100644
--- a/src/lua_gears.h
+++ b/src/lua_gears.h
@@ -11,10 +11,14 @@
 
 namespace rime {
 
+std::ostream& operator<<(std::ostream &os, const LuaErr &e);
+
 class LuaTranslation : public Translation {
 public:
   LuaTranslation(Lua *lua, an<LuaObj> f)
-    : lua_(lua), f_(f) {
+    : LuaTranslation(lua, f, "") {};
+  LuaTranslation(Lua *lua, an<LuaObj> f, string name_space)
+    : lua_(lua), f_(f), name_space_(name_space) {
     Next();
   }
 
@@ -23,11 +27,14 @@ class LuaTranslation : public Translation {
   an<Candidate> Peek() {
     return c_;
   }
+  string name_space() const { return name_space_; }
+  void set_name_space(const string& ns) { name_space_ = ns;}
 
 private:
   Lua *lua_;
   an<Candidate> c_;
   an<LuaObj> f_;
+  string name_space_;
 };
 
 class LuaFilter : public Filter, TagMatching {
@@ -38,19 +45,7 @@ class LuaFilter : public Filter, TagMatching {
   virtual an<Translation> Apply(an<Translation> translation,
                                 CandidateList* candidates);
 
-  virtual bool AppliesToSegment(Segment* segment) {
-    if ( ! tags_match_ )
-      return TagsMatch(segment);
-
-    auto r = lua_->call<bool, an<LuaObj>, Segment *, an<LuaObj>>(tags_match_, segment,  env_);
-    if (!r.ok()) {
-      auto e = r.get_err();
-      LOG(ERROR) << "LuaFilter::AppliesToSegment of " << name_space_ << " error(" << e.status << "): " << e.e;
-      return false;
-    }
-    else
-      return  r.get();
-  }
+  virtual bool AppliesToSegment(Segment* segment);
 
 private:
   Lua *lua_;
diff --git a/src/types.cc b/src/types.cc
index a8b73c4..3f32aa0 100644
--- a/src/types.cc
+++ b/src/types.cc
@@ -217,7 +217,7 @@ namespace TranslationReg {
       return 0;
 
     auto o = lua->newthreadx(L, n);
-    an<Translation> r = New<LuaTranslation>(lua, o);
+    an<Translation> r = New<LuaTranslation>(lua, o,"=lua=");
     LuaType<an<Translation>>::pushdata(L, r);
     return 1;
   }
@@ -236,6 +236,20 @@ namespace TranslationReg {
     lua_pushvalue(L, 1);
     return 2;
   }
+  bool set_name_space(T &t, const string &ns) {
+    if (auto tp = dynamic_cast<LuaTranslation *>(&t)) {
+      tp->set_name_space(ns);
+      return true;
+    }
+    return false;
+  }
+
+  string name_space(T &t) {
+    if (auto tp = dynamic_cast<LuaTranslation *>(&t)) {
+      return tp->name_space();
+    }
+    return "";
+  }
 
   static const luaL_Reg funcs[] = {
     { "Translation", raw_make },
@@ -244,14 +258,17 @@ namespace TranslationReg {
 
   static const luaL_Reg methods[] = {
     { "iter", raw_iter },
+    { "set_name_space", WRAP(set_name_space)},
     { NULL, NULL },
   };
 
   static const luaL_Reg vars_get[] = {
+    { "name_space", WRAP(name_space)},
     { NULL, NULL },
   };
 
   static const luaL_Reg vars_set[] = {
+    { "name_space", WRAP(set_name_space)},
     { NULL, NULL },
   };
 }
@@ -1212,10 +1229,7 @@ static int raw_connect(lua_State *L) {
   auto c = t.connect
     ([lua, o](I... i) {
        auto r = lua->void_call<an<LuaObj>, Context *>(o, i...);
-       if (!r.ok()) {
-         auto e = r.get_err();
-         LOG(ERROR) << "Context::Notifier error(" << e.status << "): " << e.e;
-       }
+       LOG_IF(ERROR, !r.ok()) << "Context::Notifier" << r.get_err();
      });
 
   LuaType<boost::signals2::connection>::pushdata(L, c);
@@ -1484,8 +1498,7 @@ namespace MemoryReg {
 
     auto r = lua_->call<bool, an<LuaObj>, const CommitEntry &>(memorize_callback, commit_entry);
     if (!r.ok()) {
-      auto e = r.get_err();
-      LOG(ERROR) << "LuaMemory::Memorize error(" << e.status << "): " << e.e;
+      LOG(ERROR) << "LuaMemory::Memorize" << r.get_err();
       return false;
     } else
       return r.get();