A base class for binary functions. 
 
BinaryFunction & operator=(const BinaryFunction &rhs)
 
Expression * clone() const 
It creates a new copy of this expression. 
 
TE_DEFINE_VISITABLE ST_Within(Expression *arg1, Expression *arg2)
Constructor. 
 
This is an abstract class that models a query expression. 
 
ST_Within & operator=(const ST_Within &rhs)