[转载]编程之道（the tao of programming）(2).txt

《编程之道》 高超的程序员并非致力于表面的成功

发信人: longman (龙飘飘), 信区: Algorithm
标  题: [转载]编程之道（The Tao of Programming）(2)
发信站: 飘渺水云间 (Tue May 29 22:16:20 2001), 转信

Design
Book Three
Thus spake the master programmer:
编程大师如是说：
"When program is being tested, it is too late to make design changes."
“程序被测试时再去改变它的设计已经太晚了。”
3.1
There once was a man who went to a computer trade show. Each day as he enter
ed, the man told the guard at the door:
曾经有一个人参加计算机展览，每天他进门时都对门卫说：
"I am a great thief, renowned for my feats of shoplifting. Be forewarned, fo
r this trade show shall not escape unplundered."
“先警告你，我是偷盗高手，我入室偷盗的本领闻名遐迩。这次展览会也再劫难逃。”
This speech disturbed the guard greatly, because there were millions of doll
ars of computer equipment inside, so he watched the man carefully. But the m
an merely wandered from booth to booth, humming quietly to himself.
警卫因此大动干戈，因为里面有价值百万的计算机设备，所以他牢牢盯紧了这个人，但
是这个人只是从一个摊位逛到另一个摊位，一边平静地喃喃自语。
When the man left, the guard took him aside and searched his clothes, but no
thing was to be found.
当这个人离开时，警卫搜了他的身，但是什么也没有发现。
On the next day of the trade show, the man returned and chided the guard say
ing: "I escaped with a vast booty yesterday, but today will be even better."
 So the guard watched him ever more closely, but to no avail.
展览会的第二天，这个人又对警卫说：“昨天我满载而归，但是今天我会收获更大。”
所以警卫更加小心地盯紧他，但是这样做完全于事无补。
On the final day of the trade show, the guard could restrain his curiosity n
o longer. "Sir Thief," he said, "I am so perplexed, I cannot live in peace.
Please enlighten me. What is it that you are stealing?"
展览会的最后一天，警卫再也不能忍住他的好奇心了。“小偷先生，”他说，“ 你说我
惊慌不安，请告诉我，你到底偷了什么？”。
The man smiled. "I am stealing ideas," he said.
这个人笑笑说：“我在偷想法。”
3.2
There once was a master programmer who wrote unstructured programs. A novice
 programmer, seeking to imitate him, also began to write unstructured progra
ms. When the novice asked the master to evaluate his progress, the master cr
iticized him for writing unstructured programs, saying: "What is appropriate
 for the master is not appropriate for the novice. You must understand the T
ao before transcending structure."
有一位编程大师，他写非结构化的程序，一位初学者刻意模仿他，也写非结构化的程序
。当他让大师看他的进步时，大师批评了他的非结构化程序：“ 对一位编程大师合适的
东西未必对一个初学者同样合适，在超越结构化之前，你必须理解编程之道。”
3.3
There was once a programmer who was attached to the court of the warlord of
Wu. The warlord asked the programmer: "Which is easier to design: an account
ing package or an operating system?"
###有人问一位程序员，“一个财务软件和一个操作系统哪个更容易设计？”
"An operating system," replied the programmer.
“是操作系统”，这位程序员回答说。
The warlord uttered an exclamation of disbelief. "Surely an accounting packa
ge is trivial next to the complexity of an operating system," he said.
此人大惑不解。他说：“显然一个财务软件比起操作系统来说其复杂性是微不足道的”
。
"Not so," said the programmer, "when designing an accounting package, the pr
ogrammer operates as a mediator between people having different ideas: how i
t must operate, how its reports must appear, and how it must conform to the
tax laws. By contrast, an operating system is not limited my outside appeara
nces. When designing an operating system, the programmer seeks the simplest
harmony between machine and ideas. This is why an operating system is easier
 to design."
程序员说：“不，设计财务软件时，一个程序员必须成为持不同意见的用户与计算机的
一个中介，他必须了解用户的操作习惯，报表要是什么形式，如何遵循税法。相反，一
个操作系统完全与这些外部的东西无关。设计操作系统，程序员只需要达到自己的设想
与机器之间的简单的和谐。这就是为什么操作系统反而比财务软件更容易设计。”
The warlord of Wu nodded and smiled. "That is all good and well, but which i
s easier to debug?"
这些人笑着说。“不错，但是哪一个更容易调试呢？”
The programmer made no reply.
程序员没有回答。
3.4
A manager went to the master programmer and showed him the requirements docu
ment for a new application. The manager asked the master: "How long will it
take to design this system if I assign five programmers to it?"
一个项目经理带给编程大师一个项目的需求，然后问大师：“如果我给你5个程序员，要
多少时间设计这个项目？”
"It will take one year," said the master promptly.
“一年”，大师说。
"But we need this system immediately or even sooner! How long will it take i
t I assign ten programmers to it?"
“但是我们等不了那么长时间，越快越好，如果10程序员呢？”
The master programmer frowned. "In that case, it will take two years."
大师皱了一下眉头说：“那就要花2年”。
"And what if I assign a hundred programmers to it?"
“那，100年程序员呢？”
The master programmer shrugged. "Then the design will never be completed," h
e said.
大师耸了耸肩说：“那这个项目就永远完不成了。”
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Coding
Book Four
Thus spake the master programmer:
编程大师如是说：
"A well-written program is its own heaven;
a poorly-written program is its own hell."
“写的好的程序是它自己的天堂，写的不好的程序是它自己的地狱”
4.1
A program should be light and agile, its subroutines connected like a string
s of pearls. The spirit and intent of the program should be retained through
out. There should be neither too little nor too much, neither needless loops
 nor useless variables, neither lack of structure nor overwhelming rigidity.
一个程序应该是轻灵自由的，它的子过程就象串在一根线上的珍珠。自始至终，目标明
确。增之一字节则太长，减之一字节则太短。既没有不必要的循环也没有没有被引用的
变量，既不缺少结构化也不至于僵硬呆板。
A program should follow the Law of Least Astonishment. What is this law? It
is simply that the program should always respond to the user in the way that
 astonishes him least.
一个程序应该遵循``最小惊讶原则''，什么是``最小惊讶原则''？就是说一个程序应该
最小程度地引起用户的惊讶。
A program, no matter how complex, should act as a single unit. The program s
hould be directed by the logic within rather than by outward appearances.
无论一个程序无论有多么复杂都应该是一个单一的整体。程序是被它的内部逻辑所指引
而不是它的外观表现。
If the program fails in these requirements, it will be in a state of disorde
r and confusion. The only way to correct this is to rewrite the program.
如果一个程序不能满足所要的需求，它就会处于混乱无序的状态中。唯一的出路就是重
写这个程序。
4.2
A novice asked the master: "I have a program that sometimes runs and sometim
es aborts. I have followed the rules of programming, yet I am totally baffle
d. What is the reason for this?"
一个初学者问大师：“我的一个程序有时正常有时不正常。我已经完全遵循编程的规则
，而且我完全被它弄糊涂了，到底是什么原因会导致这样呢？”
The master replied: "You are confused because you do not understand the Tao.
 Only a fool expects rational behavior from his fellow humans. Why do you ex
pect it from a machine that humans have constructed? Computers simulate dete
rminism; only the Tao is perfect.
大师说：“你困惑是因为你不了解道。只有傻瓜才会相信只要遵循别人所说就能得到想
当然的结果。为什么你要从一个人类自己构造的机器中去得到想当然的结果呢？计算机
只是决定论的产物；只有道才是唯一完美的。
The rules of programming are transitory; only the Tao is eternal. Therefore
you must contemplate the Tao before you receive enlightenment."
任何编程的规则都只适合于特定的情况，只有道才是永恒不变的。所以在你受到指引之
前要先去思考道。”
"But how will I know when I have received enlightenment?" asked the novice.
“但是我怎么知道我何时受到指引呢？”
"Your program will then run correctly," replied the master.
“当你的程序正确运行时”。大师说。
4.3
A master was explaining the nature of the Tao to one of his novices, "The Ta
o is embodied in all software -- regardless of how insignificant," said the
master.
初学者请大师解释“道法自然”。大师说：“道存在于任何软件中－－无论是多么没有
意义的软件”。
"Is the Tao in a hand-held calculator?" asked the novice.
“难道也存在于手持式的计算嚣里？”，初学者问。
"It is," came the reply.
“是的，”
"Is the Tao in a video game?" continued the novice.
“也在游戏机里？”，初学者又问到。
"It is even in a video game," said the master.
“是的，甚至也存在于游戏机里”。大师说。
"And is the Tao in the DOS for a personal computer?"
“也存在于个人计算机的DOS里吗？”
The master coughed and shifted his position slightly. "The lesson is over fo
r today," he said.
大师咳嗽了一声，稍微动了一下，说，“今天的课就到这里”。
4.4