97 Things Every Programmer Should Know

97 Things
Every Programmer Should Know

Collective Wisdom from the Experts

Edited by Kevlin Henney

Beijing · Cambridge · Farnham · Köln · Sebastopol · Taipei · Tokyo

97 Things Every Programmer Should Know
Edited by Kevlin Henney

Copyright © 2010 Kevlin Henney. All rights reserved.
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Print History:
February 2010:

First Edition.

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ISBN: 978-0-596-80948-5
[SB]

To absent friends

Contents

Contributions by Category . . . . . . . . . . . . . . . . . . . . .
Preface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .

xv
xxiii

Act with Prudence . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Seb Rose
Apply Functional Programming Principles . . . . . . . . . . . . 4
Edward Garson
Ask, “What Would the User Do?” (You Are Not the User) . . 6
Giles Colborne
Automate Your Coding Standard . . . . . . . . . . . . . . . . . . 8
Filip van Laenen
Beauty Is in Simplicity . . . . . . . . . . . . .. . . . . . . . . . .

10

Jørn Ølmheim
Before You Refactor . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Rajith Attapattu
Beware the Share . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Udi Dahan

v

The Boy Scout Rule . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Robert C. Martin (Uncle Bob)
Check Your Code First Before Looking to Blame Others . . .18
Allan Kelly
Choose Your Tools with Care . . . . . . . . . . . . . . . . . . . 20
Giovanni Asproni
Code in the Language of the Domain . . . . . . . . . . . . . .

22

Dan North
Code Is Design. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

24

Ryan Brush
Code Layout Matters . . . . . . . . . . . . . . . . . . . . . . . . .

26

Steve Freeman
Code Reviews . . . . . .. . . . . . . . . . . . . . . . . . . . . . .

28

Mattias Karlsson
Coding with Reason . . . . . . . . . . . . . . . . . . . . . . . . . 30
Yechiel Kimchi
A Comment on Comments . . . . . . . . . . . . . . . . . . . . .

32

Cal Evans
Comment Only What the Code Cannot Say . . . . . . . . . .

34

Kevlin Henney
Continuous Learning . . . . . . . . . . . . . . . . . . . . . . . . .36

Clint Shank
Convenience Is Not an -ility . . . . . . . . . . . . . . . . . . . .

38

Gregor Hohpe

vi

Contents

Deploy Early and Often . . . . . . . . . . . . . . . . . . . . . . . 40
Steve Berczuk
Distinguish Business Exceptions from Technical . . . . . . .

42

Dan Bergh Johnsson
Do Lots of Deliberate Practice. . . . . . . . . . . . . . . . . . . 44
Jon Jagger...