X 
Simple boolean expression language as a Java expressed DSL.

X.And 
"AND" logical operator

X.BinaryOp 
Abstract binary operators

X.Eq 
"equality" comparison operator.

X.Ge 
"greater or equal" comparison operator.

X.Gt 
"greater than" comparison operator.

X.In 
"containment" operator.

X.Le 
"less or equal" comparison operator.

X.Lt 
"less than" comparison operator.

X.Neq 
"not equals" comparison operator.

X.Not 
Negation logical operator

X.Or 
"OR" logical operator

X.UnaryOp 
Abstract singleoperand operator

X.Val 
Explicit value.

X.Var 
Variable of field value operator.

X.Xor 
"XOR" logical operator
