4.59 Exercise 4.59

If Ben wants to query for all of the meetings happening on Friday, he could do this:

(meeting ?division (Friday ?time))

If Alyssa P. Hacker wants to write a rule to associate persons with meeting days and times, she could do this:

(rule (meeting-time ?person ?day-and-time)

(or (meeting whole-company ?day-and-time)

(and (job ?person (?division . ?position))

(meeting ?division ?day-and-time))))

Using this, she could then find all of the meetings she has to attend on Wednesday:

(meeting-time (Hacker Alyssa P) (Wednesday ?time))

However, the results of this rule will not include the divisions that the meetings are for. This is a little suspect, especially if multiple meetings can happen at the same time. I think the meeting-time rule can be improved a little bit:

(rule (meeting-time ?person ?division ?day-and-time)

(and (meeting ?division ?day-and-time)

(or (same whole-company ?division)

(job ?person (?division . ?position)))))

(meeting-time (Hacker Alyssa P) ?division (Wednesday ?time))