diff --git a/src/headers/parsing/ParseComponents.hpp b/src/headers/parsing/ParseComponents.hpp
index 24b7322..6da557f 100644
--- a/src/headers/parsing/ParseComponents.hpp
+++ b/src/headers/parsing/ParseComponents.hpp
@@ -89,7 +89,7 @@ public:
         for (const auto& comp: components) add<T>(comp);
     }
     IS_PARSECOMPONENT
-    const ParseTree& operator<<(const T& component) const { add(component); return *this; }
+    inline const ParseTree& operator<<(const T& component) const { add(component); return *this; }
     ParseTree(): subComponents() {};
     IS_PARSECOMPONENT
     explicit ParseTree(const T& element): ParseTree() { add(element); }