diff --git a/src/interpreter.hpp b/src/interpreter.hpp
index 262b037..0940ad5 100644
--- a/src/interpreter.hpp
+++ b/src/interpreter.hpp
@@ -22,6 +22,7 @@
     void operator()(const create_&) const;
     void operator()(const delete_&) const;
     void operator()(const ls_&) const;
+    void operator()(const discard_&) const;
 
 private:
     template <typename T>