Book 4 - Coding
====


Thus spake the master programmer:

``A well-written program is its own heaven; a poorly-written
program is its own hell.''



4.1

A program should be light and agile, its subroutines
connected like a string of pearls. The spirit and intent of
the program should be retained throughout.  There should be
neither too little or too much, neither needless loops nor
useless variables, neither lack of structure nor
overwhelming rigidity.

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.

A program, no matter how complex, should act as a single
unit. The program should be directed by the logic within
rather than by outward appearances.

If the program fails in these requirements, it will be in a
state of disorder and confusion. The only way to correct
this is to rewrite the program.



4.2

A novice asked the master: ``I have a program that sometime
runs and sometimes aborts. I have followed the rules of
programming, yet I am totally baffled.  What is the reason
for this?''

The master replied: ``You are confused because you do not
understand Tao. Only a fool expects rational behavior from
his fellow humans. Why do you expect it from a machine that
humans have constructed? Computers simulate determinism;
only Tao is perfect.

``The rules of programming are transitory; only Tao is
eternal. Therefore you must contemplate Tao before you
receive enlightenment.''

``But how will I know when I have received enlightenment?''
asked the novice.

``Your program will then run correctly,'' replied the
master.



4.3

A master was explaining the nature of Tao of to one of his
novices. ``The Tao is embodied in all software - regardless
of how insignificant,'' said the master.

``Is the Tao in a hand-held calculator?'' asked the novice.

``It is,'' came the reply.

``Is the Tao in a video game?'' continued the novice.

``It is even in a video game,'' said the master.

``And is the Tao in the DOS for a personal computer?''

The master coughed and shifted his position slightly. ``The
lesson is over for today,'' he said.



4.4

Prince Wang's programmer was coding software. His fingers
danced upon the keyboard. The program compiled without an
error message, and the program ran like a gentle wind.

``Excellent!'' the Prince exclaimed, ``Your technique is
faultless!''

``Technique?'' said the programmer turning from his
terminal, ``What I follow is Tao - beyond all techniques!
When I first began to program I would see before me the
whole problem in one mass. After three years I no longer saw
this mass. Instead, I used subroutines. But now I see
nothing. My whole being exists in a formless void. My senses
are idle. My spirit, free to work without plan, follows its
own instinct. In short, my program writes itself. True,
sometimes there are difficult problems. I see them coming, I
slow down, I watch silently.  Then I change a single line of
code and the difficulties vanish like puffs of idle smoke. I
then compile the program. I sit still and let the joy of the
work fill my being. I close my eyes for a moment and then
log off.''

Prince Wang said, ``Would that all of my programmers were as
wise!''