alias wgetr="wget -rSNpk -np --execute 
  robots=off -U \"Mozilla/5.001 (windows; U; NT4.0; en-us) 
  Gecko/25250101\" $@"

#lang scheme

(define person% (class object% 
		       (init name)
		       (super-new)
		       (define current-name name)
		       (define/public (set-name name)
			 (set! current-name name))
		       (define/public (get-name)
			 current-name)))

(define (talkable-person %)
  (class % (super-new) 
	 (define/public (talk)
	   "blah blah")))

(define talking-person% (talkable-person person%))

(define gg (new talking-person% (name "GG")))
(send gg get-name)
(send gg talk)

bash-3.2$ mzscheme mixin.ss 
"GG"
"blah blah"

#lang scheme

(define person-interface (interface() get-name set-name))

(define person% (class* object% (person-interface)
			(init name)
			(define current-name name)
			(super-new)
			(define/public (get-name)
			  current-name)
			(define/public (set-name name)
			  (set! current-name name))
			))

(define gg (new person% [name "GG"]))
(send gg get-name)
(send gg set-name "Ganesh Gunasegaran")
(send gg get-name)

(is-a? gg person-interface)
(is-a? gg person%)


bash-3.2$ mzscheme oops.ss
"GG"
"Ganesh Gunasegaran"
#t
#t

Add this to .emacs

;; Comment/Uncomment region
(global-set-key (kbd "s-/") 'comment-dwim)

Toggle comment of the selected region by pressing Apple + /

#lang scheme

(define student% (class object%
                  (init name age)
                  
                  (define this-name name)
                  (define this-age age)                  
                  
                  (super-new)
                  
                  (define/public (get-name)
                    this-name)
                  
                  (define/public (set-name name)
                    (set! this-name name))
                  
                  (define/public (get-age)
                    this-age)
                  
                  (define/public (set-age age)
                    (set! this-age age))
                  ))

> (define gg (new student% [name "Ganesh"] [age 28]))
> (send gg get-name)
"Ganesh"
> (send gg get-age)
28
> (send gg set-name "GG")
> (send gg get-name)
"GG"

(define fav-color (make-parameter 'blue))

(define whats-ur-fav-color? 
  (lambda ()
    (fav-color)))
> (whats-ur-fav-color?)
blue
> (parameterize ((fav-color 'red))
             (whats-ur-fav-color?))
red