Complete up to exercise 4.56

mceval/logic-programming.rkt

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+#lang sicp
+
+;; Exercise 4.55
+
+;; Everyone supervised by Ben
+(supervisor ?x (Bitdiddle Ben))
+
+;; Everyone in the accounting division
+(job ?x (accounting . ?y))
+
+;; Everyone who lives in Slumerville
+(address ?x (Slumerville . ?y))
+
+;; Exercise 4.56
+
+;; Names and addresses of everyone supervised by Ben Bitdiddle
+(and (address ?person ?address)
+     (supervisor ?person (Bitdiddle Ben)))
+
+;; All people whose salaray is less than Ben Bitdiddle's together with
+;; their salary and Ben's salary
+(and (salary ?person ?amount)
+     (and (salary (Bitdiddle Ben) ?ben-salary)
+          (lisp-value < ?amount ?ben-salary)))
+
+;; All people who are supervised by someone who is not in the computer
+;; division, together with the supervisor's name and job.
+(and (supervisor ?person ?supervisor)
+     (job ?supervisor ?supervisor-job)
+     (not (job ?supervisor (computer . ?x))))