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KentuckyFC writes "Nobel prize-winning physicist Gerard 't Hooft has joined the likes of computer scientists Stephen Wolfram and Ed Fredkin in claiming that the universe can be accurately modeled by cellular automata. The novel aspect of 't Hooft's model is that it allows quantum mechanics and, in particular, the spooky action at a distance known as entanglement to be deterministic. The idea that quantum mechanics is fundamentally deterministic is known as hidden variable theory but has been widely discounted by physicists because numerous experiments have shown its predictions to be wrong. But 't Hooft says his cellular automaton model is a new class of hidden variable theory that falls outside the remit of previous tests. However, he readily admits that the new model has serious shortcomings — it lacks some of the basic symmetries that our universe enjoys, such as rotational symmetry. However, 't Hooft adds that he is working on modifications that will make the model more realistic (abstract)."

ijones writes "Andrew Cooke recently reviewed for Slashdot Purely Functional Data Structures, which is on my book shelf next to The Haskell School of Expression: Learning Functional Programming through Multimedia by Paul Hudak from the Yale Haskell Group. In his review, Cooke presented an overview of some available functional programming languages, such as OCaml, SML, and of course Haskell. Havoc Pennington once called Haskell 'the least-broken programming language available today.' Haskell is a purely functional, lazy, statically typed programming language. You can read more about Haskell itself here." Read on for ijones' review of The Haskell School of Expression. The Haskell School of Expression: Learning Functional Programming through Multimedia author Paul Hudak pages 363 publisher Cambridge University Press rating 9 reviewer Isaac Jones ISBN 0521644089 summary Learn to program in a functional style in Haskell by implementing graphics, music, and robots simulations.

As the title implies, The Haskell School of Expression introduces functional programming through the Haskell programming language and through the use of graphics and music. It serves as an effective introduction to both the language and the concepts behind functional programming. This text was published in 2000, but since Haskell 98 is the current standard, this is still a very relevant book.

Haskell's standardization process gives us a window into two different facets of the community: Haskell is designed to be both a stable, standardized language (called Haskell 98), and a platform for experimentation in cutting-edge programming language research. So though we have a standard from 1998, the implementations (both compilers and interpreters) are continually evolving to implement new, experimental features which may or may not make it into the next standard.

For instance, the Glasgow Haskell Compiler has implemented a meta-programming environment called Template Haskell. Haskell is also easy to extend in directions that don't change the language itself, through the use of Embedded Domain-Specific Languages (EDSLs) such as WASH for web authoring, Parsec for parsing, and Dance (more of Paul Hudak's work) for controlling humanoid robots.

Before we get too far, I should offer a disclaimer: The Haskell community is rather small, and if you scour the net, you may find conversations between myself and Paul Hudak or folks in his research group, since I use some of their software. That said, I don't work directly with Hudak or his research group.

In fact, the small size of the Haskell community is a useful feature. It is very easy to get involved, and folks are always willing to help newbies learn, since we love sharing what we know. You may even find that if you post a question about an exercise in The Haskell School of Expression , you'll get a reply from the author himself.

I consider this book to be written in a "tutorial" style. It walks the reader through the building of applications, but doesn't skimp on the concepts (indeed, the chapters are meant to alternate between "concepts" and "applications"). In some ways, the code examples make it a little difficult to jump around, since you are expected to build upon previous code. The web site provides code, however, so you can always grab that and use it to fill in the missing pieces.

For readers who wish to use this book as a tutorial, and to implement all of the examples (which is highly recommended), I suggest that you grab the Hugs interpreter and read the User's Guide while you're reading the first few chapters of The Haskell School of Expression. Hugs is very portable, free, and easy to use. It also has an interface with Emacs. Unfortunately, some of the example code has suffered from bit-rot, and certain things don't work out-of-the-box for X11-based systems. The bit-rot can be solved by using the "November 2002" version of Hugs. This is all explained on SOE's web page.

The Haskell School of Expression should be very effective for programmers who have experience in more traditional languages, and programmers with a Lisp background can probably move quickly through some of the early material. If you've never learned a functional language, I highly recommend Haskell: Since Haskell is purely functional (unlike Lisp), it will more or less prevent you from "cheating" by reverting to a non-functional style. In fact, if you've never really looked at functional programming languages, it may surprise you to learn that Haskell has no looping constructs or destructive assignment (that is, no x = x + 1). All of the tasks that you would accomplish through the use of loops are accomplished instead through recursion, or through higher-level abstractions upon recursion.

Since I was already comfortable with recursion when I started this book, it is hard for me to gauge how a reader who has never encountered recursion would find this book's explanation of the concept. The Haskell School of Expression introduces recursion early on, in section 1.4. It is used in examples throughout the book, and if you follow along with these examples, you will most certainly be using it a lot. The introduction seems natural enough to me, but I note that Hudak does not give the reader any extra insight or tricks to help them along. Not to worry, though; recursion is very natural in Haskell and the reader may not even notice that they are doing something a little tricky.

The use of multimedia was a lot of fun for me, and should quickly dispel the myth that IO is difficult in Haskell. For instance, Hudak has the reader drawing fractals by page 44, and throughout the book, the reader will be drawing shapes, playing music, and controlling animated robots.

Any book on Haskell must be appraised for its explanation of monads in general and IO specifically. Monads are a purely functional way to elegantly carry state across several computations (rather than passing state explicitly as a parameter to each function). They are a common stumbling block in learning Haskell, though in my opinion, their difficulty is over-hyped.

Since input and output cause side-effects, they are not purely functional, and don't fit nicely into a function-call and recursion structure. Haskell has therefore evolved a way to deal safely and logically with IO through the use of monads, which encapsulate mutable state. In order to perform IO in Haskell, one must use monads, but not necessarily understand them.

Some people find monads confusing; I've even heard a joke that you need a Ph.D. in computer science in order to perform IO in Haskell. This is clearly not true, and this book takes an approach which I whole-heartedly agree with. It gets the reader using monads and IO in chapter 3 without explaining them deeply until chapters 16 (IO) and 18 (monads). By the time you get there, if you have heard that monads are confusing, you might be inclined to say "how is this different from what we've been doing all along?" Over all, I was pleased with the explanation of monads, especially state monads in chapter 18, but I felt that the reader is not given enough exercises where they implement their own monads.

If you're worried that drawing shapes and playing music will not appeal to your mathematic side, you will be pleased by the focus on algebraic reasoning for shapes (section 8.3) and music (section 21.2), and a chapter on proof by induction (chapter 11).

After reading this book you will be prepared to take either of the two paths that Haskell is designed for: You can start writing useful and elegant tools, or you can dig into the fascinating programming language research going on. You will be prepared to approach arrows, a newer addition to Haskell which, like monads, have a deep relationship to category theory. Arrows are used extensively in some of the Yale Haskell group's recent work. You will see a lot of shared concepts between the animation in The Haskell School of Expression and Yale's "Functional Reactive Programming" framework, Yampa. If you like little languages, you'll appreciate how useful Haskell is for embedded domain-specific languages. It may be even more useful now that Template Haskell is in the works. Andrew Cooke described Purely Functional Data Structures as a great second book on functional programming. In my opinion, The Haskell School of Expression is the great first book you're looking for.

You can purchase Learning Functional Programming through Multimedia from bn.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.

Ubi_NL writes "According to the Register there is a close correlation between the DDOS attacks on a number of anti-spam lists and the presence of the Sobig virus. Now that Monkeys.com is gone, and spamhaus.org is taking heavy blows, are the spammers actually winning the battle by using viruses?"

Querty wrote in to tell us that ZDNet's AnchorDesk page (home of everyone's favorite person: Jesse Berst) is doing a whole big Linux Thing today. Articles Include "Take the Linux Plunge", "Resellers Key to Linux Success", "Essential Linux Tips" and "Jon's Linux Toolkit", and a (ahem) poll. It looks like Linux is mainstream now.

Rahga writes "Connectix CEO and President Roy McDonald states: We were unable to reach anyone from Sony Computer Entertainment America to comment on whether it had in fact filed anything. (legal action) " He goes on to hint at a PC-version. Tons of you are also pointing out that Pre-7 is out. Thanks to Rik van Riel.

First off, various website and software announcements: Rik van Riel wrote in to say that the The Linux Memory Management home page, including the More than 1GB Faq, as moved. Jennifer wrote in to tell us that eterm now has its own domain. Rak wrote in to send us a link to a new site aiming to keep up with GNOME Development. chrism wrote in to say that Brian Paul of Mesa Fame is looking for a new home for said software. Email if you can help. Now that the straight stuff is out of the way, some fun stuff: kweiheri tron wrote in to send us a link to a telescope that you can control online. Eli sent us a link to the Bonsai Potato. It's just crazy. Jamie Wilkinson sent us a link to www.retards.com. It's not what you might think it is. A couple of other folks have written in recently and mentioned Smartass.org. It's a nifty site. Check it out.

First off, various website and software announcements: Rik van Riel wrote in to say that the The Linux Memory Management home page, including the More than 1GB Faq, as moved. Jennifer wrote in to tell us that eterm now has its own domain. Rak wrote in to send us a link to a new site aiming to keep up with GNOME Development. chrism wrote in to say that Brian Paul of Mesa Fame is looking for a new home for said software. Email if you can help. Now that the straight stuff is out of the way, some fun stuff: kweiheri tron wrote in to send us a link to a telescope that you can control online. Eli sent us a link to the Bonsai Potato. It's just crazy. Jamie Wilkinson sent us a link to www.retards.com. It's not what you might think it is. A couple of other folks have written in recently and mentioned Smartass.org. It's a nifty site. Check it out.

Finally, a few minutes to clear out the submissions box. First up Dave Whitinger wrote in to tell us that Three Point's news has expanded in 3 lists (Press, Security and Software News). Han-Wen Nienhuys sent us a link to a project he has been working on called LilyPond. It is a sheet music layout program ala TeX. Looks pretty excellent (if you're into that sorta thing :) Bill Lynch wrote in to warn us that Dave "Zoid" Kirsch (Linux Quake Port Guy) would like some comments on support of linux libraries. Stomped has a link to Dave's .plan file. Albert Strasheim wrote in to plug a Linux t-shirt design contest. Winners get Amazon credit and free shirts, so you designers out there may want to hop over (wonder if I should submit DFTP:) Finally, Brian Vincent sent us a link to something from Graphon called GO-Global that accelerates X apps 300-1000%. AIX and Solaris already use it, but now there's a linux port.

Finally, a few minutes to clear out the submissions box. First up Dave Whitinger wrote in to tell us that Three Point's news has expanded in 3 lists (Press, Security and Software News). Han-Wen Nienhuys sent us a link to a project he has been working on called LilyPond. It is a sheet music layout program ala TeX. Looks pretty excellent (if you're into that sorta thing :) Bill Lynch wrote in to warn us that Dave "Zoid" Kirsch (Linux Quake Port Guy) would like some comments on support of linux libraries. Stomped has a link to Dave's .plan file. Albert Strasheim wrote in to plug a Linux t-shirt design contest. Winners get Amazon credit and free shirts, so you designers out there may want to hop over (wonder if I should submit DFTP:) Finally, Brian Vincent sent us a link to something from Graphon called GO-Global that accelerates X apps 300-1000%. AIX and Solaris already use it, but now there's a linux port.