(in-package :util)

(defun compare (a b)
  (cond
    ((and (consp a) (atom b))
     (setf a (car a)))
    ((and (atom a) (consp b))
     (setf b (car b))))
  (cond
    ((eql a b) 0)
    ((and (not a) b) -1)
    ((and a (not b)) 1)
    ((and (integerp a) (integerp b))
     (- a b))
    ((and (typep a '(or string character symbol))
	  (typep b '(or string character symbol)))
     (cond ((string-lessp a b) -1)
	   ((string-equal a b) 0)
	   ((string-greaterp a b) 1)))
    ((and (consp a) (consp b))
     (let ((comp (compare (car a) (car b))))
       (if (zerop comp)
	   (compare (cdr a) (cdr b))
	   comp)))
    (t
     (compare-objects a b))))

(defmethod compare-objects ((a t) (b t))
  0)

(defun lookup= (a b)
  (zerop (compare a b)))

(defun lookup/= (a b)
  (not (zerop (compare a b))))

(defun lookup< (a b)
  (< (compare a b) 0))

(defun lookup<= (a b)
  (<= (compare a b) 0))

(defun lookup> (a b)
  (> (compare a b) 0))

(defun lookup>= (a b)
  (>= (compare a b) 0))