diff --git a/bc.lua b/bc.lua
index f2ff898f4b4a..c05b70b31c91 100644
--- a/bc.lua
+++ b/bc.lua
@@ -280,25 +280,23 @@ function BaseControl:set(name, value)
       local old = self.local_nouns[name]
       self.local_nouns[name] = value
 
-      if self.listeners[name] ~= nil then
-        for id, l in pairs(self.listeners[name]) do
-          if   (l.query.ty == Query.Change.ty and value ~= old)
-            or (l.query.ty == Query.Rising.ty and value > old)
-            or (l.query.ty == Query.Falling.ty and value < old)
-            or (l.query.ty == Query.Equals.ty and value == l.query.v)
-            or (l.query.ty == Query.Above.ty and value > l.query.v)
-            or (l.query.ty == Query.Below.ty and value < l.query.v)
-              then
-            if l.callback ~= nil then
-              l.callback(value)
-            else
-              self.network:send(l.addr, {
-                ty=Message.ListenNotify,
-                noun=name,
-                id=id,
-                value=value,
-              })
-            end
+      for id, l in pairs(self.listeners[name] or {}) do
+        if   (l.query.ty == Query.Change.ty and value ~= old)
+          or (l.query.ty == Query.Rising.ty and value > old)
+          or (l.query.ty == Query.Falling.ty and value < old)
+          or (l.query.ty == Query.Equals.ty and value == l.query.v)
+          or (l.query.ty == Query.Above.ty and value > l.query.v)
+          or (l.query.ty == Query.Below.ty and value < l.query.v)
+            then
+          if l.callback ~= nil then
+            l.callback(value)
+          else
+            self.network:send(l.addr, {
+              ty=Message.ListenNotify,
+              noun=name,
+              id=id,
+              value=value,
+            })
           end
         end
       end