...

python/_set.py

@@ -95,4 +95,4 @@ class set:
         return '{'+ ', '.join([repr(i) for i in self._a.keys()]) + '}'
     
     def __iter__(self):
-        return self._a.keys()
+        return iter(self._a.keys())

src/pocketpy.h

@@ -897,7 +897,7 @@ inline void init_builtins(VM* _vm) {
         for(auto& item : self.items()){
             if(!first) ss << ", ";
             first = false;
-            Str key = CAST(Str&, item.first);
+            Str key = CAST(Str&, item.first).escape();
             Str value = CAST(Str&, vm->py_json(item.second));
             ss << key << ": " << value;
         }