Real World Haskell

by O'Sullivan, Bryan; Goerzen, John; Stewart, Don

• ISBN13: 9780596514983
• ISBN10: 0596514980
• Edition: 1st
• Format: Paperback
• Copyright: 2008-12-05
• Publisher: Oreilly & Associates Inc

Summary

This is the book for software developers who want to learn Haskell and use it to do real work. There are a number of books on Haskell out there, but they're all either textbooks or academic books; the textbooks use Pascal as a language for teaching computer science. There isn't anything out there that shows you how to use Haskell to write software that's actually useful. There's been a significant upsurge of interest in Haskell and other functional programming languages. It's not clear what's driving this interest, but one of the factors may be the importance of concurrent programming and new computer architectures. The book introduces readers to the language, but it's a fairly fast and brief tutorial, rather than a textbook. It pays special attention to real- world issues like I/O, performance, dealing with external data, databases, concurrency, and web applications.

Author Biography

Bryan O'Sullivan is an Irish hacker and writer who likes distributed systems, open source software, and programming languages. He was a member of the initial design team for the Jini network service architecture (subsequently open sourced as Apache River). He has made significant contributions to, and written a book about, the popular Mercurial revision control system. He lives in San Francisco with his wife and sons. Whenever he can, he runs off to climb rocks.

John Goerzen is an American hacker and author. He has written a number of real-world Haskell libraries and applications, including the HDBC database interface, the ConfigFile configuration file interface, a podcast downloader, and various other libraries relating to networks, parsing, logging, and POSIX code. John has been a developer for the Debian GNU/Linux operating system project for over 10 years and maintains numerous Haskell libraries and code for Debian. He also served as President of Software in the Public Interest, Inc., the legal parent organization of Debian. John lives in rural Kansas with his wife and son, where he enjoys photography and geocaching.

Don Stewart is an Australian hacker based in Portland, Oregon. Don has been involved in a diverse range of Haskell projects, including practical libraries, such as Data.ByteString and Data.Binary, as well as applying the Haskell philosophy to real-world applications including compilers, linkers, text editors, network servers, and systems software. His recent work has focused on optimizing Haskell for high-performance scenarios, using techniques from term rewriting.

Table of Contents

Dedication

Preface

Have We Got a Deal for You!

What to Expect from This Book

What to Expect from Haskell

A Brief Sketch of Haskell's History

Helpful Resources

Conventions Used in This Book

Using Code Examples

Safari(r) Books Online

How to Contact Us

Acknowledgments

Getting Started

Your Haskell Environment

Getting Started with ghci, the Interpreter

Basic Interaction: Using ghci as a Calculator

Command-Line Editing in ghci

Lists

Strings and Characters

First Steps with Types

A Simple Program

Types and Functions

Why Care About Types?

Haskell's Type System

What to Expect from the Type System

Some Common Basic Types

Function Application

Useful Composite Data Types: Lists and Tuples

Functions over Lists and Tuples

Function Types and Purity

Haskell Source Files, and Writing Simple Functions

Understanding Evaluation by Example

Polymorphism in Haskell

The Type of a Function of More Than One Argument

Why the Fuss over Purity?

Conclusion

Defining Types, Streamlining Functions

Defining a New Data Type

Type Synonyms

Algebraic Data Types

Pattern Matching

Record Syntax

Parameterized Types

Recursive Types

Reporting Errors

Introducing Local Variables

The Offside Rule and Whitespace in an Expression

The case Expression

Common Beginner Mistakes with Patterns

Conditional Evaluation with Guards

Functional Programming

Thinking in Haskell

A Simple Command-Line Framework

Warming Up: Portably Splitting Lines of Text

Infix Functions

Working with Lists

How to Think About Loops

Anonymous (lambda) Functions

Partial Function Application and Currying

As-patterns

Code Reuse Through Composition

Tips for Writing Readable Code

Space Leaks and Strict Evaluation

Writing a Library: Working with JSON Data

A Whirlwind Tour of JSON

Representing JSON Data in Haskell

The Anatomy of a Haskell Module

Compiling Haskell Source

Generating a Haskell Program and Importing Modules

Printing JSON Data

Type Inference Is a Double-Edged Sword

A More General Look at Rendering

Developing Haskell Code Without Going Nuts

Pretty Printing a String

Arrays and Objects, and the Module Header

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