#|
multiline
comment
|#
"string with special \n \t chars"
; comment
(define (fn a)
 (let* ((b (+ a 1)))
 (if (= a 1)
 #t
 #f))) ;; another comment
(define c (lambda (x)
 (let loop ((i 0))
 (unless (= i 10)
 ;; print some chars
 (display #\' #\#)
 (loop (+ i 1))))))
((if (= 0 0) * +) 5 2)
;; numbers
(define pi 3.14159)
(define circle-area
 (lambda (radius)
 (* pi radius radius)))
(define (circle-area radius)
 (* pi radius radius))
(define (blah)
 (define (foo) 55)
 (define (woo) 42)
 (+ (foo) (woo)))
(define (repeat-forever)
 (display "I will not play with Scheme in class.")
 (repeat-forever))
(define (all-atoms-are-numeric? tree)
 (call-with-current-continuation
 (lambda (return) ;bind RETURN to the current cont
 (define (walk tree)
 (cond ((null? tree))
 ((pair? tree) ;pair? is like consp
 (walk (car tree))
 (walk (cdr tree)))
 ((number? tree))
 (else (return #f)))) ;found a non-number -- return false
 (walk tree)
 #t))) ;else return true
(cond ((number? x) "A number.")
 ((string? x) "A string.")
 (else "Beats me!"))
(cond ((assoc key a-list) => cdr)
 (else #f))
(letrec ((even? (lambda (n) (if (= n 0) #t (odd? (- n 1)))))
 (odd? (lambda (n) (if (= n 0) #f (even? (- n 1))))))
 (even? 42))
(let counting ((n 10))
 (cond ((< 0 n)
 (write n)
 (counting (- n 1)))))
(define (list . arguments) arguments)
(define-syntax my-or
 (syntax-rules ()
 ((my-or) #f)
 ((my-or e) e)
 ((my-or e1 e2 ...)
 (let ((temp e1))
 (if temp temp (my-or e2 ...))))))
(define-syntax syntax-rules
 (lambda (x)
 (syntax-case x ()
 ((_ (i ...) ((keyword . pattern) template) ...)
 (syntax (lambda (x)
 (syntax-case x (i ...)
 ((dummy . pattern) (syntax template))
 ...)))))))