Feeds

Programming in Haskell

Yes, Melinda, there is a choice: Functional Programming

Maximizing your infrastructure through virtualization

Book review While it may appear that object oriented programming has achieved dominance in terms of programming language paradigms, there still exist outposts that refuse to submit to the benefits of polymorphism, encapsulation, and object inheritance.

It's not just that there is a hard-core group sticking to procedural coding in C and refusing to go the Java/C#/Python/Ruby route. There are also those who have taken the functional programming route to programming nirvana, particularly those who use that purist functional language, Haskell. And it's a topic that seems to be of increasing interest to the broader development community as well.

Despite the conceptual differences between object oriented and pure procedural languages, they do in fact share common roots and a number of key features. Chief among these is that programs manipulate data and state. Computer scientists characterise this style of programming as imperative programming – the developer writes a series of statements that tell the computer what to do, changing the state of variables in order to complete whatever task the program is performing.

In contrast, functional programming (FP) has no concept of state – there are no variables that the developer manipulates. Instead, there are a series of functions which are applied to data and evaluated. Some of the data that these functions are applied to are themselves functions, and may deliver other functions as results. On the face of it this might seem like a bizarre and alien concept, and indeed the first time that one comes across Haskell, or any other functional programming language, it does seem odd.

There is obviously a strongly mathematical flavour to Haskell, which this slim introductory volume does nothing to dispel. The academic tone is partly because the book is geared to the computer science student (complete with excercises at the end of each chapter), but it's also recognition of the roots of Haskell in the academic community.

The book opens with some introductory background and then moves on very quickly to syntax and program structure. The explanations are generally clear, and the text is illustrated with simple examples. The author has assumed no prior programming experience, but those who've programmed before in a non-FP language would probably appreciate a bit more guidance on the differences between the FP and non-FP way of doing things.

The book looks at key concepts such as data typing, curried functions, folding, filters, and so on. What becomes apparent is that the language is concise, elegant and extremely powerful. It leaves the developer reasoning about algorithms without having to worry too much about the plumbing. Those who've programmed with APL, for example, will find a fair degree of familiarity. Similarly, those who've come across lambda functions (which derive from FP) in other languages, such as Python or Ruby, will find that Haskell presents a much purer expression of functional programming.

For the practicing developer looking to utilise Haskell in action, however, this book is not ideal. Its emphasis is more on giving the reader a solid conceptual grounding rather than on more concrete programming tasks. While there are some extended examples in the latter part of the book, it's still by no means a very practically-focused tutorial.

Nevertheless, whether it's closures in Java, lambda functions in Python or Ruby, XSLT transformations, or new ideas in parallel computation, FP is providing input to many different areas of modern development. This book provides a good introduction to the concepts.

Programming in Haskell

Programming in HaskellVerdict: Functional programming is generating possible new approaches to many development issues - perhaps most importantly to parallel programming on multicore systems. This book is a good place to get your head around some of its ideas, even if you don't intend to add Haskell to your program language arsenal right now.

Author: Graham Hutton

Publisher: Cambridge University Press

ISBN: 0521692695

Media: Book

List Price: £23.99

Current Reg price: £23.99 (inc VAT)

Buy this book at Register Books (price subject to change). ®

Reducing security risks from open source software

More from The Register

next story
HIDDEN packet sniffer spy tech in MILLIONS of iPhones, iPads – expert
Don't panic though – Apple's backdoor is not wide open to all, guru tells us
Captain Kirk sets phaser to SLAUGHTER after trying new Facebook app
William Shatner less-than-impressed by Zuck's celebrity-only app
Do YOU work at Microsoft? Um. Are you SURE about that?
Nokia and marketing types first to get the bullet, says report
Microsoft takes on Chromebook with low-cost Windows laptops
Redmond's chief salesman: We're taking 'hard' decisions
Cheer up, Nokia fans. It can start making mobes again in 18 months
The real winner of the Nokia sale is *drumroll* ... Nokia
EU dons gloves, pokes Google's deals with Android mobe makers
El Reg cops a squint at investigatory letters
Chrome browser has been DRAINING PC batteries for YEARS
Google is only now fixing ancient, energy-sapping bug
prev story

Whitepapers

Seven Steps to Software Security
Seven practical steps you can begin to take today to secure your applications and prevent the damages a successful cyber-attack can cause.
Consolidation: The Foundation for IT Business Transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.
Designing a Defense for Mobile Applications
Learn about the various considerations for defending mobile applications - from the application architecture itself to the myriad testing technologies.
Build a business case: developing custom apps
Learn how to maximize the value of custom applications by accelerating and simplifying their development.
Consolidation: the foundation for IT and business transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.