;; define.txt

(define x 4)
x
=> 4

(define (f x) (+ x 1))
(f 5)
=> 6

(define (make-adder n)
  (lambda (x) (+ x n)))
(define f (make-adder 10))
(f 5)
=> 15

;; rest args
(define (f x y z...)
  (pair x (pair y (pair z... ()))))
(f 1 2 3 4 5)
=> (1 2 (3 4 5))

;; keyword args
(define (f :foo :bar)
  (pair foo (pair bar ())))
(f)
=> (#f #f)
(f :foo 33)
=> (33 #f)
(f :bar "z" :foo)
=> (#t "z")
(f :foo :bar)
=> (#t #t)

;; rest args & keywords

(define (f x y z... :this :that)
  (pair x (pair y (pair z... (pair this (pair that ()))))))
(f 1 2 3 4 5 :this 100)
=> (1 2 (3 4 5) 100 #f)