diff --git a/src/headers/lex.hpp b/src/headers/lex.hpp
index 7c3132f..21e081b 100644
--- a/src/headers/lex.hpp
+++ b/src/headers/lex.hpp
@@ -3,7 +3,8 @@
 
 #include <memory>
 #include <vector>
-#include <sstream>
+#include <string>
+#include <ostream>
 
 struct tok {
     enum type {