AF (and PE) expressions currently have AND and OR operators. These work either logically or (if both operands are integer) in a bitwise fashion. There should also be an XOR operator that works the same way, to avoid the messy construct (A AND NOT B) OR (B AND NOT A). Also, since NOT only returns true/false (rather than complement if an integer) there is no way to implement XOR in a bitwise fashion. So functions or operators ('~' anyone?) to do one's and two's complement would be useful too.
