Add a ^ (power) operator to the expression calculator of Section 15.6.3. For example, 2 ^ 3 evaluates to 8. As in mathematics, your power operator should be evaluated from the right. That is, 2 ^ 3 ^ 2 is 2 ^ (3 ^ 2), not (2 ^ 3) ^ 2. (That’s more useful because you could get the latter as 2 ^ (3 × 2).)