yao2030

(define (and->if exp)
  (expand-and-clauses (and-clauses exp)))
(define (expand-and-clauses clauses)
  (if (null? clauses)
      true
      (let ((first (car clauses))
            (rest (cdr clauses)))
        (if (false? first)
            'f
            (make-if first (expand-and-clauses rest) false)))))

yao2030

def evaluatePoly(poly, x):
    result = 0.0
    for i in range(len(poly)):
        result += poly[i] * x ** i
    return result
# poly = [0.0, 0.0, 5.0, 9.3, 7.0]
# x = -13
# print evaluatePoly(poly, x)

def computeDeriv(poly):

yao2030

(load "stream-map.ss")
(load "ex59")

(define (scale-stream s f)
  (stream-map (lambda (x) (* x f)) s))
(define (mul-series s1 s2)
  (cons-stream (* (stream-car s1)
		  (stream-car s2))
	       (add-streams
		(scale-stream (stream-cdr s2) (stream-car  s1))

yao2030

(load "stream-map.ss")
(load "ex59")

(define (scale-stream s f)
  (stream-map (lambda (x) (* x f)) s))
(define (mul-series s1 s2)
  (cons-stream (* (stream-car s1)
		  (stream-car s2))
	       (add-streams
		(scale-stream (stream-cdr s2) (stream-car  s1))

yao2030

(define (make-queue)
  (let ((front-ptr '())
	(rear-ptr '()))
    (define (set-front-ptr! item)
      (set! front-ptr item))
    (define (set-rear-ptr! item)
      (set! rear-ptr item))
    (define (empty-queue?)
      (null? front-ptr))
    ;; (define (print-queue)

yao2030

;; selectors
(define (front-ptr queue) (car queue))
(define (rear-ptr queue) (cdr queue))
(define (set-front-ptr! queue item) (set-car! queue item))
(define (set-rear-ptr! queue item) (set-cdr! queue item))
(define (empty-queue? queue) (null? (front-ptr queue)))
;; constructors
(define (make-queue) (cons '() '()))
;; selectors
(define (front-queue queue)

yao2030

(define (random-in-range low high)
  (let ((range (- high low)))
    (+ low (random range))))
(define (experiment x1 x2 y1 y2)
  (let ((a (random-in-range x1 x2))
	(b (random-in-range y1 y2))
	(c (/  (+ x1 x2) 2.0))
	(d (/  (+ y1 y2) 2.0))
	(r (/ (- x1 x2) 2.0)))
    (<= (+ (square (- a c))

yao2030

;; 3.1
(define (make-accumulator init)
  (lambda (x)
    (set! init (+ init x))
    init))
;; 3.2
(define (make-monitored f)
  (let ((count 0))
    (lambda (m)
      (cond ((eq? m 'how-many-calls) count)

yao2030

(define (memq item x)
  (cond ((null? x) false)
	((eq? item (car x)) x)
	(else (memq item (cdr x)))))
;; huffman coding (information theory)
(define (make-leaf symbol weight)
  (list 'leaf symbol weight))
(define (leaf? object)
  (eq? (car object) 'leaf))
(define (symbol-leaf x) (cadr x))

yao2030

;; quit message
(fset 'yes-or-no-p 'y-or-n-p)
;;把缺省的 major mode 设置为 text-mode, 而不是几乎什么功能也
;;没有的 fundamental-mode.
(setq default-major-mode 'text-mode)
(setq initial-major-mode 'text-mode)
;;光标靠近鼠标指针时，让鼠标指针自动让开，别挡住视线。
(mouse-avoidance-mode 'animate)
;;显示列号
(setq column-number-mode t)