The pragmatic programmer from journeyman to master

Prepared exclusively for Zach What others in the trenches say about The Pragmatic Programmer “The cool thing about this book is that it’s great for keeping the programming process fresh [The book] helps you to continue to grow and clearly comes from people who have been there.” Kent Beck, author of Extreme Programming Explained: Embrace Change “I found this book to be a great mix of solid advice and wonderful analogies!” Martin Fowler, author of Refactoring and UML Distilled “I would buy a copy, read it twice, then tell all my colleagues to run out and grab a copy This is a book I would never loan because I would worry about it being lost.” Kevin Ruland, Management Science, MSG-Logistics “The wisdom and practical experience of the authors is obvious The topics presented are relevant and useful By far its greatest strength for me has been the outstanding analogies—tracer bullets, broken windows, and the fabulous helicopter-based explanation of the need for orthogonality, especially in a crisis situation I have little doubt that this book will eventually become an excellent source of useful information for journeymen programmers and expert mentors alike.” John Lakos, author of Large-Scale C++ Software Design Prepared exclusively for Zach “This is the sort of book I will buy a dozen copies of when it comes out so I can give it to my clients.” Eric Vought, Software Engineer “Most modern books on software development fail to cover the basics of what makes a great software developer, instead spending their time on syntax or technology where in reality the greatest leverage possible for any software team is in having talented developers who really know their craft well An excellent book.” Pete McBreen, Independent Consultant “Since reading this book, I have implemented many of the practical suggestions and tips it contains Across the board, they have saved my company time and money while helping me get my job done quicker! This should be a desktop reference for everyone who works with code for a living.” Jared Richardson, Senior Software Developer, iRenaissance, Inc “I would like to see this issued to every new employee at my company .” Chris Cleeland, Senior Software Engineer, Object Computing, Inc Prepared exclusively for Zach The Pragmatic Programmer Prepared exclusively for Zach This page intentionally left blank Prepared exclusively for Zach The Pragmatic Programmer From Journeyman to Master Andrew Hunt David Thomas ADDISON–WESLEY An imprint of Addison Wesley Longman, Inc Reading, Massachusetts Harlow, England Menlo Park, California Berkeley, California Don Mills, Ontario Sydney Bonn Amsterdam Tokyo Mexico City Prepared exclusively for Zach Many of the designations used by manufacturers and sellers to distinguish their products are claimed as trademarks Where those designations appear in this book, and Addison– Wesley was aware of a trademark claim, the designations have been printed in initial capital letters or in all capitals Lyrics from the song “The Boxer” on page 157 are Copyright c 1968 Paul Simon Used by permission of the Publisher: Paul Simon Music Lyrics from the song “Alice’s Restaurant” on page 220 are by Arlo Guthrie, c 1966, 1967 (renewed) by A PPLESEED M USIC I NC All Rights Reserved Used by Permission The authors and publisher have taken care in the preparation of this book, but make no express or implied warranty of any kind and assume no responsibility for errors or omissions No liability is assumed for incidental or consequential damages in connection with or arising out of the use of the information or programs contained herein The publisher offers discounts on this book when ordered in quantity for special sales For more information, please contact: AWL Direct Sales Addison Wesley Longman, Inc One Jacob Way Reading, Massachusetts 01867 (781) 944-3700 Visit AWL on the Web: www.awl.com/cseng Library of Congress Cataloging-in-Publication Data Hunt, Andrew, 1964 – The Pragmatic Programmer / Andrew Hunt, David Thomas p cm Includes bibliographical references ISBN 0-201-61622-X Computer programming I Thomas, David, 1956– II Title QA76.6.H857 1999 005.1 dc21 99–43581 CIP Copyright c 2000 by Addison Wesley Longman, Inc All rights reserved No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher Printed in the United States of America Published simultaneously in Canada ISBN 0-201-61622-X Text printed in the United States on recycled paper at Courier Stoughton in Stoughton, Massachusetts 25th Printing Prepared exclusively for Zach February 2010 For Ellie and Juliet, Elizabeth and Zachary, Stuart and Henry Prepared exclusively for Zach This page intentionally left blank Prepared exclusively for Zach Contents F OREWORD xiii P REFACE xvii A P RAGMATIC P HILOSOPHY 1 The Cat Ate My Source Code 2 Software Entropy Stone Soup and Boiled Frogs Good-Enough Software Your Knowledge Portfolio 12 Communicate! 18 A P RAGMATIC A PPROACH 25 The Evils of Duplication 26 Orthogonality 34 Reversibility 44 10 Tracer Bullets 48 11 Prototypes and Post-it Notes 53 12 Domain Languages 57 13 Estimating 64 T HE B ASIC T OOLS 71 14 The Power of Plain Text 73 15 Shell Games 77 16 Power Editing 82 17 Source Code Control 86 18 Debugging 90 19 Text Manipulation 99 20 Code Generators 102 ix Prepared exclusively for Zach ... they dragged their big, dirty hoses into the house, they stopped—with the fire raging to roll out a mat between the front door and the source of the fire They didn’t want to mess up the carpet A... be done to salvage the situation Does code have to be thrown out? Educate them on the value of refactoring (see Refactoring, page 184) Do you need to spend time prototyping to determine the best... smart? Aren’t they just as focused on details as other programmers? The answer is that they paid attention to what they were doing while they were doing it—and then they tried to it better Imagine