;; Simple class that roughly models a point on the cartesian plane. Can display 
;; it's coordinates, or convert them to polar. Demonstrates basic functionality of 
;; our class model. 

(class point (parent:) (constructor_args: x y) 
	(ivars: (yval y) (xval x) ) 
	(methods: 
		(getx () xval) 
		(gety () yval) 
		(display () (begin 
			(display "Coords: x=") (display xval) 
			(display ", y=") (display yval) (newline))) 
		(setx (newx) (set! xval newx)) 

	;; Converts the points coords to polar 
		(polar () 
			(let (
			   (radius (sqrt (+ (* xval xval) (* yval yval))))
 			   (angle (/ (truncate (* (atan (/ yval xval)) 
						  (/ 36000 (* 2 3.1415)))) 100))) 
			(list radius angle))) 
		(dist (p2) 
			(let ((x2 (p2 'getx)) 
			      (y2 (p2 'gety))) 
			  (sqrt (+ (expt (- x2 xval) 2) (expt (- y2 yval) 2))))))) 

;; Another class that models a drunk person. The central methods merely reverse the 
;; list input by the user and echo it back. Demonstrates the use of the *this* 
;; construct as well as recursion, as well as method overloading. 
;; Note that methods can also call *other methods* defined in that class, by using *this*
;; Of course this could include *recursive* calling of a method to itself!

(class drunkard (parent:) (constructor_args: n yrs) 
	(ivars: (age yrs) (name n) (bloodlevel 20) (death (+ 5 yrs)) ) 
	(methods: (say (who string) 
			(begin (display "Hey ") (display who) 
			(display "! ") (*this* 'say string) )) 

		  (say (string) 
			(begin (display name) 
			    (display " blubbers: Did you say ") 
			    (display (*this* 'reverse string))))
		  (complain () 
			(begin (display name) 
			    (display " blubbers: Oh man, my bloodlevel is  ") 
			    (display bloodlevel) (display " and I will be dead by  ")
				(display death))) 
		  (reverse (string) 
			(if (null? string) () (append (*this* 'reverse (cdr string)) 
						      (list (car string)))))))