(in-package :cs325-user)

(defparameter *facts*
  '((bird isa animal)
    (pet isa animal)
    (canary isa bird)
    (penguin isa bird)
    (animal can-fly no)
    (animal has-owner no)
    (pet has-owner yes)
    (bird can-fly yes)
    (penguin can-fly no)
    (tweety isa pet)
    (tweety isa canary)
    (chilly isa penguin)))


(defun foo (x)
  (cons x (cons (bar x) (baz x))))

(defun bar (x)
  (mapcan (lambda (fact)
            (and (eql (car fact) x)
                 (eql (cadr fact) 'isa)
                 (list (caddr fact))))
          *facts*))

(defun baz (x)
  (mapcan (lambda (fact)
            (and (eql (car fact) x)
                 (not (eql (cadr fact) 'isa))
                 (list (cdr fact))))
          *facts*))

(defun triples-to-frames ()
  (mapcar 'foo (remove-duplicates (mapcar 'car *facts*))))


(defparameter *frames* (triples-to-frames))

(defun get-frame (subj) (assoc subj *frames*))

(defun frame-value (subj pred)
  (cadr (assoc pred (cddr (get-frame subj)))))

(defparameter *absts* nil)

(defun all-absts (subj)
  (or (assoc subj *absts*)
      (add-absts subj)))

(defun add-absts (subj)
  (let ((absts (remove-duplicates (collect-absts subj))))
    (setq *absts* (cons absts *absts*))
    absts))

(defun collect-absts (subj)
  (cons subj
        (mapcan 'collect-absts (cadr (get-frame subj)))))

(defun infer (subj pred)
  (some (lambda (abst) (frame-value abst pred))
        (all-absts subj)))


;;; for testing
(defun show-all ()
  (pprint
   (mapcar 'foo '(animal bird canary pet tweety penguin chilly))))