Answer to Exercise 3

| ANSWER TO EXERCISE 3
| Briefly: provide a `GamePreRoutine` which tests to see if `second` is an object, rather than `nothing` or a number. If it is, check whether the object has a `second_before` rule (i.e. test the condition `(object provides second_before)`). If it has, send the `second_before` message to it, and return the reply as the return value from `GamePreRoutine`.

Back to the exercise in section 9

Mechanically translated to HTML from third edition as revised 16 May 1997. Copyright © Graham Nelson 1993, 1994, 1995, 1996, 1997: all rights reserved.