diff --git a/resources/3rdparty/exprtk/exprtk.hpp b/resources/3rdparty/exprtk/exprtk.hpp
index 079ee1b6f..a86c45509 100755
--- a/resources/3rdparty/exprtk/exprtk.hpp
+++ b/resources/3rdparty/exprtk/exprtk.hpp
@@ -99,7 +99,7 @@ namespace exprtk
             return (('a' <= c) && (c <= 'z')) ||
             (('A' <= c) && (c <= 'Z'))
 #ifdef MODIFICATION
-            || ('.' == c) || ('_' == c)
+            || ('_' == c)
 #endif
             ;
         }