--- a/src/main.h	Thu Feb 27 23:07:40 2020 +0200
+++ b/src/main.h	Fri Feb 28 19:24:33 2020 +0200
@@ -25,6 +25,7 @@
 #include "utility.h"
 #include "maths.h"
 #include "geometry.h"
+#include "functional.h"
 
 namespace settingGroups
 {