diff --git a/version0.4/ebnf.cpp b/version0.4/ebnf.cpp
index c0115ca..2155797 100644
--- a/version0.4/ebnf.cpp
+++ b/version0.4/ebnf.cpp
@@ -16,6 +16,10 @@
 <1><scalar> ::=
 	<number> //NUMBER
 	<string> //STRING
+	<(> <!> <identifier>|<scalar> <)>//first
+	<!> <identifier>|<scalar>//then
+	<(> <identifier>|<scalar> <+>|<->|<*>|</>|<~>|<and>|<or>|<==>|<!=>|<<>|<<=>|<>>|<>=> <identifier>|<scalar> <)> //first
+	<identifier>|<scalar> <+>|<->|<*>|</>|<~>|<and>|<or>|<==>|<!=>|<<>|<<=>|<>>|<>=> <identifier>|<scalar> //then
 <2><scalars> ::=
 	<scalar>|<scalars>         <,> <scalar>|<identifier>
 	<identifier>|<identifiers> <,> <scalar>