Book: Beautiful Code

Beautiful Code: Leading Programmers Explain How They Think (Theory in Practice (O'Reilly)).

--- Foreword ---
I got my first job as a programmer in the summer of 1982. Two weeks after I started, one of the system administrators loaned me Kernighan and Plauger's The Elements of Programming Style (McGraw-Hill) and Wirth's Algorithms + Data Structures = Programs (Prentice Hall). They were a revelation—for the first time, I saw that programs could be more than just instructions for computers. They could be as elegant as well-made kitchen cabinets, as graceful as a suspension bridge, or as eloquent as one of George Orwell's essays.

Time and again since that summer, I have heard people bemoan the fact that our profession doesn't teach students to see this. Architects are taught to look at buildings, and com-posers study one another's scores, but programmers—they look at each other's work only when there's a bug to fix; even then, they try to look at as little as possible. We tell students to use sensible variable names, introduce them to some basic design patterns, and then wonder why so much of what they write is so ugly.

This book is our attempt to fix this. In May 2006, I asked some well-known (and not so well-known) software designers to dissect and discuss the most beautiful piece of code they knew. As this book shows, they have found beauty in many different places. For some, it lives in the small details of elegantly crafted software. Others find beauty in the big picture—in how a program's structure allows it to evolve gracefully over time, or in the techniques used to build it.

Wherever they find it, I am grateful to our contributors for taking time to give us a tour. I hope that you enjoy reading this book as much as Andy and I have enjoyed editing it, and that it inspires you to create something beautiful, too.

--- How This Book Is Organized ---
Chapter 1, A Regular Expression Matcher, by Brian Kernighan, shows how deep insight into a language and a problem can lead to a concise and elegant solution.

Chapter 2, Subversion's Delta Editor: Interface As Ontology, by Karl Fogel, starts with a well-chosen abstraction and demonstrates its unifying effects on the system's further development.

Chapter 3, The Most Beautiful Code I Never Wrote, by Jon Bentley, suggests how to measure a procedure without actually executing it.

Chapter 4, Finding Things, by Tim Bray, draws together many strands in Computer Science in an exploration of a problem that is fundamental to many computing tasks.

Chapter 5, Correct, Beautiful, Fast (in That Order): Lessons from Designing XML Verifiers, by Elliotte Rusty Harold, reconciles the often conflicting goals of thoroughness and good performance.

Chapter 6, Framework for Integrated Test: Beauty Through Fragility, by Michael Feathers, presents an example that breaks the rules and achieves its own elegant solution.

Chapter 7, Beautiful Tests, by Alberto Savoia, shows how a broad, creative approach to testing can not only eliminate bugs but turn you into a better programmer.

Chapter 8, On-the-Fly Code Generation for Image Processing, by Charles Petzold, drops down a level to improve performance while maintaining portability.

Chapter 9, Top Down Operator Precedence, by Douglas Crockford, revives an almost forgotten parsing technique and shows its new relevance to the popular JavaScript language.

Chapter 10, The Quest for an Accelerated Population Count, by Henry S. Warren, Jr., reveals the impact that some clever algorithms can have on even a seemingly simple problem.

Chapter 11, Secure Communication: The Technology Of Freedom, by Ashish Gulhati, discusses the directed evolution of a secure messaging application that was designed to make sophisticated but often confusing cryptographic technology intuitively accessible to users.

Chapter 12, Growing Beautiful Code in BioPerl, by Lincoln Stein, shows how the combination of a flexible language and a custom-designed module can make it easy for people with modest programming skills to create powerful visualizations for their data.

Chapter 13, The Design of the Gene Sorter, by Jim Kent, combines simple building blocks to produce a robust and valuable tool for gene researchers.

Chapter 14, How Elegant Code Evolves with Hardware: The Case of Gaussian Elimination, by Jack Dongarra and Piotr Luszczek, surveys the history of LINPACK and related major software packages to show how assumptions must constantly be re-evaluated in the face of new computing architectures.

Chapter 15, The Long-Term Benefits of Beautiful Design, by Adam Kolawa, explains how attention to good design principles many decades ago helped CERN's widely used mathematical library (the predecessor of LINPACK) stand the test of time.

Chapter 16, The Linux Kernel Driver Model: The Benefits of Working Together, by Greg Kroah-Hartman, explains how many efforts by different collaborators to solve different problems led to the successful evolution of a complex, multithreaded system.

Chapter 17, Another Level of Indirection, by Diomidis Spinellis, shows how the flexibility and maintainability of the FreeBSD kernel is promoted by abstracting operations done in common by many drivers and filesystem modules.

Chapter 18, Python's Dictionary Implementation: Being All Things to All People, by Andrew Kuchling, explains how a careful design combined with accommodations for a few special cases allows a language feature to support many different uses.

Chapter 19, Multidimensional Iterators in NumPy, by Travis E. Oliphant, takes you through the design steps that succeed in hiding complexity under a simple interface.

Chapter 20, A Highly Reliable Enterprise System for NASA's Mars Rover Mission, by Ronald Mak, uses industry standards, best practices, and Java technologies to meet the requirements of a NASA expedition where reliability cannot be in doubt.

Chapter 21, ERP5: Designing for Maximum Adaptability, by Rogerio Atem de Carvalho and Rafael Monnerat, shows how a powerful ERP system can be developed with free software tools and a flexible architecture.

Chapter 22, A Spoonful of Sewage, by Bryan Cantrill, lets the reader accompany the author through a hair-raising bug scare and a clever solution that violated expectations.

Chapter 23, Distributed Programming with MapReduce, by Jeff Dean and Sanjay Ghemawat, describes a system that provides an easy-to-use programming abstraction for large-scale distributed data processing at Google that automatically handles many difficult aspects of distributed computation, including automatic parallelization, load balancing, and failure handling.

Chapter 24, Beautiful Concurrency, by Simon Peyton Jones, removes much of the difficulty of parallel programs through Software Transactional Memory, demonstrated here using Haskell.

Chapter 25, Syntactic Abstraction: The syntax-case Expander, by R. Kent Dybvig, shows how macros—a key feature of many languages and systems—can be protected in Scheme from producing erroneous output.

Chapter 26, Labor-Saving Architecture: An Object-Oriented Framework for Networked Software, by William R. Otte and Douglas C. Schmidt, applies a range of standard object-oriented design techniques, such as patterns and frameworks, to distributed logging to keep the system flexible and modular.

Chapter 27, Integrating Business Partners the RESTful Way, by Andrew Patzer, demonstrates a designer's respect for his programmers by matching the design of a B2B web service to its requirements.

Chapter 28, Beautiful Debugging, by Andreas Zeller, shows how a disciplined approach to validating code can reduce the time it takes to track down errors.

Chapter 29, Treating Code As an Essay, by Yukihiro Matsumoto, lays out some challenging principles that drove his design of the Ruby programming language, and that, by extension, will help produce better software in general.

Chapter 30, When a Button Is All That Connects You to the World, by Arun Mehta, takes you on a tour through the astounding interface design choices involved in a text-editing system that allows people with severe motor disabilities, like Professor Stephen Hawking, to communicate via a computer.

Chapter 31, Emacspeak: The Complete Audio Desktop, by T. V. Raman, shows how Lisp's advice facility can be used with Emacs to address a general need—generating rich spoken output—that cuts across all aspects of the Emacs environment, without modifying the underlying source code of a large software system.

Chapter 32, Code in Motion, by Laura Wingerd and Christopher Seiwald, lists some simple rules that have unexpectedly strong impacts on programming accuracy.

Chapter 33, Writing Programs for "The Book", by Brian Hayes, explores the frustrations of solving a seemingly simple problem in computational geometry, and its surprising resolution.