public class RegExprSymbols {

   public static final char UNION_OP = '+';
   public static final char CONCAT_OP = '.';
   public static final char STAR_OP = '*';
   public static final char LEFT_PAREN = '(';
   public static final char RIGHT_PAREN = ')';
   public static final char LAMBDA = 'L';
   public static final char NULL_SET = 'N';

}