diff --git a/src/csg/parser.cpp b/src/csg/parser.cpp
index 961d079add22cd4b7032e95dd480e4d94c612ee4..cb169634ef14072421ea7ed7967a0896b46c6838 100644
--- a/src/csg/parser.cpp
+++ b/src/csg/parser.cpp
@@ -544,9 +544,9 @@ template <> struct action<hull> {
   }
 };
 
-std::optional<std::string> get_name(AttrMap curr_attr) {
+std::optional<std::string> get_name(const AttrMap &curr_attr) {
   if (curr_attr.count("$name")) {
-    auto quoted_name = std::get<std::string>(curr_attr["$name"]);
+    auto quoted_name = std::get<std::string>(curr_attr.find("$name")->second);
     auto name = quoted_name.substr(1, quoted_name.length() - 2);
     return name;
   }