interpolates filename

src/loaders/abstract/Conf.cpp

@@ -73,9 +73,12 @@ Conf::Conf(std::string filename, int LOG_LEVEL ): JSON_Loader(LOG_LEVEL ), slog(
     std::string jval_s;
     bool jval_b;
 
+
     // prepare context spaghetti
     this->override_context = false;
 
+    interpolate( filename);
+
     try {
         // load the test file.
         this->load_json_file( filename );