Domain: pragprog.com
Stories and comments across the archive that link to pragprog.com.
Stories · 9
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'Pragmatic Programmer' Author Andy Hunt Loves Arduino, Hates JavaScript (bestprogrammingbooks.com)
Andy Hunt is one of the 17 software developers who wrote the Agile Manifesto, and he co-authored The Pragmatic Programmer. Now Slashdot reader cerberusss writes: In an interview with Best Programming Books, Andy Hunt mentions he "hates languages that introduce accidental complexity, such as JavaScript -- what a nightmare of pitfalls for newbies and even seasoned developers... My go-to languages are still Ruby for most things, or straight C for systems programming, Pi or Arduino projects." Furthermore, he mentions that "I tend to do more experimenting and engineering than pure code writing, so there's occasionally some soldering involved ;). Code is just one tool of many."
Andy writes that he also likes Elixir, talks about Agile, reveals how he survived his most challenging project, and says the biggest advancement in programming has been the open source movement. ("Imagine trying to study chemistry, but the first half of the elements were patent-protected by a major pharma company and you couldn't use them...") And he also answered an interesting follow-up question on Twitter: "Do you feel validated in an age of Node and GitHub? Some of your best chapters (scripting and source control) are SOP now!"
Andy's reply? "We've made some great progress, for sure. But there's much to be done still. E.g., You can't ship process." -
Book Review: CoffeeScript: Accelerated JavaScript Development
Michael J. Ross writes "For decades, programmers have written computer code in one language, and then programmatically translated that code into another, lower-level form (typically machine code that can be run directly by a microprocessor, or some sort of bytecode that can be interpreted by a virtual machine). For instance, source code written in C or C++ is compiled and assembled into machine code. In web programming, there are emerging languages and other tools for translating code into JavaScript. For instance, Google Web Toolkit allows the programmer to create web apps in Java. The latest addition to this category is CoffeeScript, a language that can be compiled into JavaScript, and is intended to reduce source code size and clutter by incorporating some of the best operators from other Web scripting languages, particularly Ruby. It is also the topic of a new tutorial, CoffeeScript: Accelerated JavaScript Development." Read on to learn what Michael thinks of this book. CoffeeScript: Accelerated JavaScript Development author Trevor Burnham pages 138 pages publisher Pragmatic Bookshelf rating 5/10 reviewer Michael J. Ross ISBN 978-1934356784 summary A fast-paced tutorial of CoffeeScript. This book is authored by Trevor Burnham, who is credited as one of the early contributors to the project by Jeremy Ashkenas (the creator and project lead of CoffeeScript) in his foreword to the book. Published by Pragmatic Bookshelf on 3 August 2011, under the ISBN 978-1934356784, CoffeeScript: Accelerated JavaScript Development fills only 138 pages, which is certainly a change of pace from the majority of programming tomes now being released. This book's material is grouped into six chapters, plus four appendices — aside from a preface, which introduces CoffeeScript as well as a word game, which is used as the example project throughout the book. Oddly enough, the preface mentions jQuery, but not as one of the well-known attempts to streamline JavaScript code.
The first chapter, "Getting Started," begins by briefly explaining how to install Node and npm (Node Package Manager). These instructions assume that you are following along in a Linux environment or some emulation thereof. They also seem to assume that nothing goes wrong in any of the steps, because no troubleshooting guidance or references are provided. Given the number of moving parts required to get CoffeeScript running, as well as the technical pitfalls that could ensnare a Windows or Mac user, the author should have provided more clear and detailed installation instructions. Also, readers unfamiliar with Linux/Unix may be puzzled by some of the instructions. For instance, page 3 appears to state that the way to check that those two aforesaid packages are on your path, is to simply type in "PATH" (whereas what is needed is "echo $PATH"). From that point forward, the narrative gradually becomes more opaque, with cursory coverage of text editor plug-ins, the "coffee" command line compiler, REPL, "the soak" (an existential chain operator), and the limitations of trying to debug CoffeeScript code. It is quite possible that by the end of this chapter, many readers will decide to not bother trying to learn CoffeeScript, and instead to stick with plain JavaScript, possibly supplemented with jQuery (which is not to say that jQuery code is any easier to read).
In the next three chapters, the author presents the basics of CoffeeScript, including how to: define and use functions and their arguments; test conditionals; throw and catch exceptions; understand variable scoping and context; create arrays using splats; accept input from the console; create objects, arrays, and soaks (in more detail than before); iterate over collections; match patterns; define namespaces using modules; and create prototypes and classes. He makes extensive use of examples, which thankfully are concise (unlike some programming books whose example code span far too many lines, and sometimes even multiple pages — forcing the reader to dig through the code, trying to find the important lines). Also, the brevity of CoffeeScript syntax is undoubtedly a factor. However, his concise style extends to the narrative as well, and will likely cause newbies to have to read the material several times — and even then wonder whether they fully grasp the concepts. It seems that the author understands CoffeeScript extremely well, but is not always able to communicate that knowledge to the reader in a patient and comprehensible manner.
Chapter 5 is a primer on jQuery, and is apparently included in the book so that the example application (the word game) can be made to work in a web browser — since none of the code or narrative (aside from the example app) appears to be related to CoffeeScript. It would have been more efficient to simply point the reader to an online jQuery tutorial, and then present only the CoffeeScript-specific differences — or just briefly explain how to load CoffeeScript files in an HTML file, which could have been done in a sidebar. The last chapter demonstrates how to run CoffeeScript on a web server, utilizing Node.js, and also explores how the lack of threads in JavaScript can impact Node programming. The example project is made multiplayer using Node, Connect, and WebSocket.
The appendices provide answers to the end-of-chapter exercises, alternative methods of running CoffeeScript code, a JavaScript cheat sheet, and a list of a half dozen bibliographic references. This book concludes with a suspiciously-short index, at less than three pages long, which appears to provide only the first or earliest occurrences of the major terms. Consequently, anyone who tries to use this book as a reference work for looking up key terms quickly — or for finding their later occurrences — will likely need to obtain an electronic version of the book, since all e-readers have search functionality. Furthermore, the index is missing some key terms used in the text, such as "function callbacks" and "arbitrary expressions" — heck, it's even missing "expressions," a fundamental concept in any programming language.
Prospective readers who wish to learn more about the book, can visit Pragmatic Bookshelf's page, which offers brief descriptions of the book and its author — as does O'Reilly Media's page. But, as of this writing, only the former makes available an e-book version, pre-publication reader comments, a discussion forum, the example source code used in the book, and a link to a page for reporting errata, which already has more than half a dozen items listed. More are present in the text: "add [a] multiplayer capability" (page xx); a lone ")" missing its matching "(" (in Exercise 6, page 34); "in a lot in functions" (page 107; should read "in a lot of functions"); "a[n] overhead" (page 110); "everyone and their dog is" (page 116).
The author's writing style is sometimes quirky, which in most cases adds a bit of levity, but occasionally leads to the misuse of terms, e.g., array ranges usage described as "fantastical" (page 43). "BDFL" (page xiii) will prove puzzling at first to most readers. On page xvi, the reader is told that JavaScript "contains multitudes." — multitudes of what? And nothing can excuse the groan-inducing "automagically" (page 100).
In terms of the ordering of the topics, one of the most exasperating aspects of this book is the way that many language concepts — such as chained comparisons, and variables being true or false (or "truthy" or "falsy") — are not presented up front, on their own, but mixed in with discussions of other topics, including development of the game application, and even in the answers to the chapter questions (Appendix 1). This makes the book generally unsuitable as a reference, especially when combined with a disappointing index.
One might assume that the modest size of this book is a result of the small size of the language itself. But another factor is surely the pithy presentation style for even some of the most important concepts in the language. Perhaps worst of all — especially from the perspective of someone relatively new to programming — some basic concepts are not addressed, or the example code does not address common use cases. For instance, in CoffeeScript, how does one create a block consisting of multiple lines of code? On page 17, indentation is briefly mentioned, but the sample code shows single-line blocks only. Other important ideas are "saved as an exercise" (which may induce flashbacks to exasperating technical college textbooks). Some readers may conclude that the author didn't want to make the effort of fully describing the language, in a more canonical fashion, which would have resulted in a much longer, but more valuable book.
It is unclear as to how much of the likely mystification and frustration of the average reader will be due to the writing choices made by the author, and how much can be blamed on the sometimes cryptic syntax of CoffeeScript, evident in the discussion of topics such as function binding (Chapter 2) and keywords (e.g., from page 106, "what.x and @x are, of course, equivalent if and only if what is this." Of course!). Readers are told in the introduction that they do not need to be experts in JavaScript to understand the book's material, and can be amateurs (page xviii). But there are several places in the book where intermediate-level knowledge, at a minimum, would be needed. That sort of difficult material may be another point in the CoffeeScript journey where some readers will decide to eschew learning the language.
The production quality of the book is fine, except that the chosen font's ratio of height to width is more than what is usually found in books nowadays; when combined with inadequate spacing among the words within many of the sentences, it makes it difficult for the reader to rapidly scan the material. The e-book version reflects the same minor problem. Yet it makes excellent use of color for syntactically highlighting the code — a feature not seen in the print version.
So if you would like to do some JavaScript programming, but without writing any JavaScript, then one possible place to start your journey is CoffeeScript: Accelerated JavaScript Development. As of this writing, it is the only CoffeeScript book on the market. Yet should the language continue growing in popularity, then more substantial and recommendable books will probably become available.
Michael J. Ross is a freelance web developer and writer.
You can purchase CoffeeScript: Accelerated JavaScript Development from amazon.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page. -
Hello, Android Third Edition
eldavojohn writes "The third edition of Hello, Android brings the book up to date on Android versions from 1.5 to 2.2 (FroYo). The book is predominantly tied to the Eclipse editing environment with several pages devoted to screen shots of the IDE. As the title suggests, this book aims to give the user the equivalent of a "Hello, world!" application in Android and succeeds in doing that but doesn't take the reader much further. From creating a sudoku application with increasing support to dabbling in OpenGL ES, the book's prime audience are people who know a little Java (with no aversion to Eclipse) and XML but absolutely no Android. You can find the source for all the examples." Keep reading for the rest of eldavojohn's review. Hello, Android: Introducing Google's Mobile Development Platform author Ed Burnette pages 300 publisher The Pragmatic Programmers rating 8/10 reviewer eldavojohn ISBN 978-1934356562 summary An introduction to creating several kinds of basic Android Mobile Applications; a "Hello World" primer for Android. The first aspect of this book that jumps out at me is that it assumes the user is using Eclipse — even late in the book like on page 231, an entire page is a screenshot of the project creation wizard in Eclipse. While this might be helpful for initiates to Eclipse, it seemed like a bit of overkill at times when actions in Ecipse are revisited throughout the brief book. For example that same screenshot with different options checked can be found engulfing page 10. "If you don't want to use Eclipse (there's one in every crowd)" says the author on page 4 before referring the reader to Android's command line reference. It gets to the point that when Burnette is going to sign his app at the end, he uses an Eclipse wizard.
The second aspect of this book that jumped out at me is that Android apps are written by extending Java classes and utilizing a very verbose XML. So between the overridden class methods and the layout meta data in the XML, there is a lot of code consuming vertical space in the book. Ellipses are provided to avoid redundancy in some instances but in others it seems there is no avoiding the space consumption. A strength of the book is that, when possible, it shows how to do something simple in both XML and Java and gives reasoning for picking a certain way the rest of the book.
The chapters are laid out with brief introductions and "Fast-Forwards" at the end of each chapter that try to push the user past this Hello, Android introduction to complex concepts. The book is well divided with part one (chapters 1 and 2) providing instructions for setting up your emulator and the basics of Android like a state transition diagram showing how all Android applications transition through Java methods in a life cycle. Part two (chapters 3 through 6) builds the sudoku application with increasing support. Part three (chapters 7 through 10) focus on more complex aspects of Android like device sensors, SQLite and OpenGL. The fourth and final section delves into the future of multi-touch on Android, writing for all resolutions and devices as well as publishing to the Android Market. Throughout the book the author takes care to to mention when you will need to put in a permissions requirement in the manifest file when utilizing something on the device.
In creating the sudoku application, Burnette does a good job at introducing the reader to some basic concepts like procedural designing versus declarative designing and Dips versus Sps. The author introduces the automatically managed R.java file and the first extension of android.app.Activity with a good explanation of how we're going to add menus from XML strings. This chapter nicely sets up the sudoku game to have an opening screen, a settings menu, a theme and exiting the game. It is lengthy but introduces the reader to click listeners as well as explicit information about how to debug. Android 2.2 adds a cute debug level of Log.wtf() which stands for "What a Terrible Failure."
Following that chapter, the author delves into some basic two dimensional graphical capabilities involving extending View in order to manipulate the canvas object inside onDraw. The chapter sums up drawables and gives a short example of text in a circle before returning to the graphics in our sudoku application. Burnette shows explicitly how to draw the game board and give it a nice embossed effect, how to add and center numbers in each of their cells, how to override key events to bring up an input screen with only valid numbers and how to continuously update the game screen. The chapter even goes as far as showing you how to shade the squares in order to give hints to the user. One thing I did not care for in this chapter (and something that persists through the rest of the book) is that the author has no qualms with calling a method in code (like calculateUsedTiles on page 68) and not defining what it does or how it works until the end of the chapter twenty pages later. Given that its signature is descriptive and it's not key to understanding Android, it's probably the best way to teach but left me doing a lot of page flipping since I like understanding apps from the bottom up. Something else to note about this chapter is that the author mentions on page 70 that he experienced "many false starts" of trying different approaches like multiple ImageView classes in XML before finding the fastest and easiest way of having only one view. There's just a couple paragraphs on this in a side box but I really wish the author had expanded on this as it sounds like a vital part of the learning Android process.
What good is a phone app without some sound? Chapter five covers Android's MediaPlayer which Burnette calls "a fickle beast" although it improves with each release of Android. The chapter also touches on playing video in Android which takes just a few lines of code. The author helps the reader by continually explaining what happens in Android when the device is rotated (in these examples the video restarts since the app is recreated). He explains how to avoid this several different ways. He also discusses why using a background service for music isn't a great idea if you intend the music to end when your program ends. By the end of the chapter, you've got some music for your sudoku app.
The next chapter very briefly covers local data storage. This is not the SQLite chapter but rather the PreferenceActivity API as well as the instance state stored via the Bundle in Android's application stack. The author doesn't spend a lot of time on these and wraps the chapter up with a brief description of accessing the internal file system as well as an external SD card.
The seventh chapter covers the need for a browser capability inside your Android application. At first I thought this would be very rarely used (you've already got a web browser) but the author points out that when you need some ability past basic text views, you might opt instead to provide that file through a lean web browser in Android as opposed to a basic test viewer. The author argues this isn't as crazy as it seems because you don't want to waste your time enhancing a text view with more and more functionality when the web browser can do that already. So you get a wrapper around WebKit that allows you to add another view to your application resulting in a browser. Should this connect to the internet, the author explains how to ask for permission to do so and how to access those pages inside your application. The next part of the chapter is probably going to put a lot of security minded folks on edge and the author makes sure to explain very carefully that allowing JavaScript to call Java can be dangerous. So internal to the WebView class, the author demonstrates JavaScript in the web browser invoking your method in Android (and vice versa). Finally the chapter covers the intricacies of interfacing with web services. What the author did really well in this section was discuss his methods of how he came about adding millisecond delays to accommodate the user. The other great thing that makes this chapter so lengthy is that the author introduces threads both through ExecutorService and Handler.
Chapter eight covers GPS and other sensors your device might have that are supported through the latest Android API. The author takes care to understand how you need to setup your emulator if you are testing this on your computer and discusses listening for updates from sensors as well as interpreting that data. Unsurprisingly, the Android API has a MapActivity class to extend for applications that wish to impose data onto a map. I feel the author could have spent more time on the more novel sensor types that are becoming prevalent in cell phones but the GPS and maps might be adequate for an introductory book.
The ninth chapter is an introduction to SQLite in Android. Android supports other data storage solutions like db4o but the author sticks to SQLite and covers all SQL relational database aspects up to a simple cursor. It's done very well and anyone with a little knowledge of SQL should be able to create, modify and update tables inside Android applications with this chapter. A very interesting thing about this chapter is that it covers how to implement inter-process communication by way of a content provider. Android utilizes URIs that programmers can define to provide a framework for storage. The book is mediocre at describing both SQLite and ContentProviders in this chapter although I felt like the ContentProvider has enough material to deserve its own chapter — even in an introductory book. I personally feel it would be interesting to consider a chapter devoted to defining a content provider with reuse by a community intended. We get an EVENTS and EVENTS_ID example but I feel this falls short of the real beauty of ContentProviders.
The next chapter is a venture into three dimensional graphics in OpenGL ES (embedded systems). Twenty pages isn't a lot of space to work with when you're discussing OpenGL but this is a good basic introduction that leaves the reader with the means to do very basic OpenGL. The chapter starts off with some good fundamentals but also carefully explains that your devices might not have 3D hardware. The API is still there but the lag might be intolerable. The author thanks John Carmack for "single-handedly" saving us from Direct3D and starts off on the very verbose code of OpenGL. In it, there are great explanations on some basic options like ambient, diffuse and specular lighting as well as discussions of fixed versus floating point. Several pages later we have a transparent rotating cube with an Android image for a surface.
Chapter eleven is devoted to the buggiest part of Android: multi-touch. A side note titled "Warning: Multi-bugs Ahead" warns the reader about how problematic the following code is going to be and how it might perform differently on different quality of hardware. As Burnette builds out the image viewing application it's a lot of similar code to view an image with the new stuff revolving around debugging logs to give the reader key insight into how the author's phone interpreted his multi-touch interactions. Dragging and pinching are covered to zoom and move the image in the viewer and seems simple enough with the exception of bugs.
Twelve will show you how to build widgets and implement live wallpapers. To a lot of developers this chapter might be a turn off but to a lot of people looking to make money with Android, this seemed like the fastest route. The example just displays a semi-transparent "Hello World!" string but it is then demonstrated how an overriding the update allows you to put date or whatever else you might need to display. The live wallpaper seemed to me like the perfect way to drain the battery on a phone. Although more complicated than the widget, the chapter covers extending the Engine class to provide a drawing engine that will redraw the background — even with our OpenGL code from a previous chapter that the author then implements. The author really goes the distance on the live wallpaper, even explaining how to extend the surface of your wallpaper so that when you transition to another part of your space it slides the rotating cube. For better or for worse, you too can have a continuous rendering of OpenGL code for your home screen!
Chapter thirteen addresses the "fragmentation" issue that so many people have been criticizing Android for. It discusses declaring and demanding an API version as well as building different emulators out on your computer in order to run your application (although earlier in the book, the author heavily criticized the emulator as being terribly slow compared to the real hardware and I experienced the same thing with my Motorolla DROID). The author does a great job of discussing the unfortunately lengthy and complicated process of preparing your software for all hardware. From subclassing to reflection to delegation/factory, he analyzes each one and explains the strengths and weaknesses. If you're having problems with your application across hardware, this chapter is a great starting point. In the next piece of this chapter, the author calls out the Android API on a bug in the ImageView class that prevents the setImageMatrix from working in some cases (this is from 1.5 and has since been fixed). For those of you who are seriously dependent on Android, the author describes in detail his five steps in discovering and addressing this bug with the final step being a peak at the commit comments to the source tree. It's good to see an author doing legwork like this and telling the story but it's also a little unnerving to see the bug. Nevertheless, I applaud the author on this frank discussion. The final parts of this chapter are spent addressing screen size (an increasing issue with tablets) and installation by way of the SD card (something that can be auto or preferred).
The final chapter addresses publishing to the Android market and provides some actually really good insight into how one should approach this and how to interact with your user community. I'd like to note a couple things that the author lists as lessons learned. The first I found interesting was "you can make a paid app free, but you can't make a free app paid." What that means is if you publish something as free and then you update the app to move a piece of what was one free functionality to requiring payment, the backlash might destroy your app's user base. The other thing is something I flat out don't agree with: "If possible, I suggest you perform frequent updates, every two weeks or so." He claims it makes users happy and gives them a feeling of support as well as bumping it up to the top of the recently updated apps in the Market. I personally find it annoying and if I have an app that I use infrequently that frequently requests updates, I uninstall it. Case in point for me is TuneWiki Social Media Player. It seemed every other week that app was requiring an update and since I used it seldom, it was promptly uninstalled. I don't know if I'm alone in this sentiment but I found this chapter to be very insightful with the exception to that suggestion.
The appendices of this book were actually fairly interesting. I didn't know what the subset of the current Android app was for the Java Standard Edition 5.0 library. You can find a list of packages that will be unavailable to you like much of javax. The author also gives great pointers like try to avoid the expensive reflection no matter how elegant it might be for you.
This book is well written with only a few minor editing mistakes. It has a lot of illustrations which are often Eclipse screen shots. While some aspects of this book might alienate a few users, it is a great learning tool for its intended audience. I found it to be "okay" for my needs but perhaps was geared a bit more towards a more novice programmer.
You can purchase Hello, Android: Introducing Google's Mobile Development Platform from amazon.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page. -
Programming Clojure
eldavojohn writes "Programming Clojure by Stuart Halloway was very near to the perfect book for me. It covers many things common to many Lisp languages while highlighting in moderate detail the things that make Clojure unique and worthy of some attention. The book spends a large amount of time dealing with the intricacies of interfacing fluidly with Java (down to a package rewrite inside a large project). This fits me perfectly as a Java programmer, and I now feel ready to experiment with peppering functional language capabilities into an object oriented language. The book also strives to show how to simplify multithreading through functional programming, which is good because I find multithreading in Java a serious headache that few are good at. Programming Clojure, released in May 2009, is currently the only book out there devoted to Clojure, and the introduction is written by the language's creator, Rich Hickey, who says, 'What is so thrilling about Stuart's book is the extent to which he "gets" Clojure.' The book earns its place on the Pragmatic Bookshelf by guiding the user through rewriting a part of Ant into a new build tool called Lancet — adding to the project what you just learned about Clojure at the end of each chapter." Keep reading for the rest of eldavojohn's review. Programming Clojure author Stuart Halloway pages 304 publisher The Pragmatic Bookshelf rating 8/10 reviewer eldavojohn ISBN 978-1-934356-33-3 summary A firm definition of Clojure via examples coupled with the beginnings of actually programming Clojure. First, a lot of you are probably wondering what Clojure is and asking me why you should care at all about it. Well, Clojure is a functional programming (FP) language that runs on top of the extremely pervasive Java Virtual Machine and in doing so seems to offer a simpler way of multithreaded programming. It belongs to the family of languages that are Lisps and as a result this book covers a lot of remedial material that is common to other Lisp languages. If you're a serious lisp programmer, you'll be able to skip some of this book (the intro will guide you). Clojure has rarely been mentioned on Slashdot with the resulting comments revealing largely confusion or considering it a buzzword. It's going to be hard to write this review about the book instead of the language being that 99% of what I know about Clojure comes from this book. If you work through this book linearly, you must also use the command line read-eval-print loop (REPL) that, similar to Ruby's IRB, allows you to get hands on with Clojure and Halloway's examples.
Both Hickey and Halloway are very active in Clojure development. In fact, Halloway has a video out on types and protocols, new developments in Clojure 1.2 since the book went to print. Halloway does a good job at providing examples, keeping the book pragmatic and showing you the "wrong" way before incrementally showing you how to correctly accomplish various goals in Clojure. But he loses two points on this review for two reasons. One is that he over evangelizes about Clojure. It would lend a lot more credibility to everything else he says if he would just relent and abstain a bit from painting Clojure as the best language for any task. This ties into my second point which is the fact that books on programming languages are supposed to give the reader two very valuable things: knowledge of when to use the language and knowledge of when not to use the language. Programming Clojure is lacking in the latter--this is not a unique problem as most books about a language really sell their language. All too often in my professional career I see a solution and think, "Wow, that really was not the right tool for the job." (I'm looking at you, Java) Clojure definitely has its strengths and weaknesses despite very little evidence of the latter in this book although I was directed to a QCon presentation where the author speaks more about where Clojure excels in real life.
That said, the book is a great fit for the object oriented Java developer who does not also code a lisp-like language regularly. I say that because Chapter Two deals with reviewing all of the facets of Clojure--most of which are found in other Lisp languages which might be seen as remedial to a proficient Lisp developer. However, before you skip it entirely, there are important notes that Halloway injects into these chapters ranging from how not to do things in Clojure to the minute differences and implications they hold. Chapter Five dives into the fundamentals and features of functional programming in Clojure. This chapter was especially useful to me as I'm not used to languages featuring things like lazy sequences, caching of results or tail-call optimization. Working through the examples in Chapter Five really opened my eyes to some of the more powerful aspects of FP. Like how an infinite sequence can easily be handled by Clojure and its laziness allows you to only pay for what you need from that sequence. While definitions of infinite sequences are also possible in Haskell or Python, Clojure brings this capability to the JVM (not that anything is preventing a more verbose Java library from handling such structures).
Chapter Three focuses a lot on Clojure's interaction with Java and does a great job of showing you how to rewrite part of your Java project into Clojure and run it on the JVM. This includes calling Java from Clojure, creating and compiling Clojure into java classes, handling Java exceptions in Clojure and ends with the beginning work in Lancet (the build tool the book strives to create using what we learn in each chapter). It also contains a bit on optimizing your performance when working with Java in Clojure. This theme continues through the book as Halloway knows that one of Clojure's main selling points is that it can be so much faster than Java if you're willing to put in the extra work and planning to utilize pure functional programming.
In Java, everything is an object. In Scheme, everything is a list. Well in Clojure, the main staple is sequences which brings us to Chapter Four: Unifying Data with Sequences. While this chapter succeeds in teaching how to load data into sequences, how to consume data from sequences and how to force evaluation of lazy sequences, it felt like one of the weakest chapters in the book. This is all necessary in learning Clojure but Halloway skimps on examples and could stand to add some more examples on what is and isn't seq-able, seq-ing on various things and performing functions on various things.
Multicore chips are all the rage these days. And right now it seems that developers are by and large content with coding single threaded applications. But that may change in the future when the user expects more than a few cores in usage. In the introduction, Halloway argues a few reasons why we all should use Clojure and one of those reasons happens to be the somewhat sound logic that we will all have cores coming out of our ears in the near future. That means that as a developer you have the option to spawn more threads which means coordination of threads which means you will be forced to do the dirty dance of concurrency. Chapter Six is entirely devoted to this and, honestly, I reread a lot of this chapter as there are several update mechanisms and models that you can use to manage concurrency in Clojure. Unsurprisingly there is no silver bullet for concurrency even in Clojure. This book has but a handful of figures and their formatting leaves much to be desired but the two in this chapter are necessary references for deciding if you should use refs and software transactional memory, atoms, agents, vars or classic Java locks. This is a potent chapter that ends with a snake game implementation in Clojure demonstrating some basic concurrency. While Clojure protects you from some classically complex issues and may make concurrency vastly more succinct, it still requires a lot of thought and planning. Halloway provides good direction but clearly hands on experience is a necessity in this realm.
Chapter Seven focuses entirely on macros and is somewhat disheartening in that it presents an extremely powerful feature of Clojure that is also very complex. Halloway gives two rules and an exception for Macro Club. The first rule is: "Don't Write Macros." The second rule is: "Write Macros if That Is the Only Way to Encapsulate a Pattern." The exception is you can also write macros if it makes calling your code easier. Halloway does a good job of explaining the basics of macros in Clojure and breaks them down via a taxonomy into categories and examples of macros in Clojure. Macros are a necessity when you're trying to augment Clojure by adding features to it or if you are creating a Domain-Specific Language (DSL). Macros in Clojure do seem easier than macros in most other Lisp languages. At the end of Chapter Seven, you create a basic DSL for Lancet which was helpful even though I was left feeling helpless in the face of macros. Despite the complexity of macros in Chapter Seven, Eight's multimethods are similar to Java polymorphism and was much easier to wrap my head around than macros. Multimethods are used very infrequently (seven times in the five thousand lines that compose the Clojure core).
Chapter Nine is unfortunately less than twenty pages and deals with "Clojure in the Wild." You would think that a book in the series of Pragmatic Programmer would have more pragmatism than the features of a language with Lancet but let's face it--Clojure is a relatively young language. Nine covers automated tests, data access and web development. The automated testing is a short section on Clojure's test-is packaging. The database stuff appears to be little more than wrappers around the already mature JDBC. The web development consists of an intro to Compojure which is similar to web.py and Sinatra. Compojure shows a lot of promise in reducing the amount of code one needs to write a basic web application. It lacks the feature set and support that Rails has with rapidly building CRUD applications but holds a lot of potential to be flushed out into something similarly powerful. Halloway says his introductions to these projects should "whet your appetite for the exciting world of Clojure development" but I think a more accurate description is that these brief brushes with functional projects leaves the reader ravenously blinded by hunger for more.
Some final thoughts on the book: I caught only two very minor typos in the book. It's all English and code. There were no pictures or illustrations in this book except for one on page 96 in which a tiny drawing appears named Joe who asks a question about vectors. Oddly enough, I didn't find Joe on any of the other three hundred pages. It was very easy to work through this book from cover to cover and the example code was very instrumental in my understanding of Clojure. As a Java monkey, rereading sections seemed a requirement although the book is concise enough for me to enjoy in my free time over one week. Halloway cites mostly websites and utilizes tinyurl to reference blogs like Steve Yegge's blog and frequently he references Wikipedia. Only three of his many citations are other printed books (although one of them is Gödel, Escher, Bach: An Eternal Golden Braid). Halloway's greatest strength is the engaging examples (like the Hofstadter Sequence) that he picks and provides to the user and I hope that future editions of the book build on this as well as expand on the growing base of Clojure projects out there. His github is rife with both instructive and pragmatic examples that could stand to be included in a future book.
Some final thoughts on the language: Clojure holds a lot of potential that is yet to be realized. I cannot say yet whether the succinct syntax offers a good balance between quick coding and readability. To the uninitiated, the code can look like a jumble of symbols. Yes, we escape the verbosity of Java and the kingdom of nouns but is what Clojure offers (a neighboring kingdom of verbs) better? While Clojure is concise, it requires a lot of keywords which required a lot of usage look up when starting. Clojure code is potent and powerful. A mere five thousand lines of Clojure code create your engine--the core of the language. I assume this brevity is due to ingenious reuse that Clojure can offer but I would hate to be the person to maintain that code if I was not the author. What's better is that this code is quickly conjured at the REPL if you wish to read it yourself or augment a feature. A sage coworker who has seen much more than I in this business of software development recommended Clojure to me. He was right that it is a very interesting and innovative language but in my opinion it has a long way to go before it becomes the next Ruby or Java. Clojure needs an equivalent to Ruby on Rails and it's fighting an uphill battle against all the developers like myself that left college with so much object oriented coding and so little functional programming (although Scheme is my alma mater's weed out course). If you find yourself stagnating and are thirsty for some continuing education in the form of a stimulating challenge, I recommend Clojure (and this book on Clojure). Hopefully Clojure's full potential is realized by the community and it finds its deserved place in many developer's tool sets as the right tool for some jobs.
You can find Programming Clojure in three DRM-free formats and hard copy from the publisher's site. For a sample of the author's writing and to get a feel for how he injects Clojure code into it, check out his blogs on his company's website.
You can purchase Programming Clojure from amazon.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page. -
Ubuntu Kung Fu
Lorin Ricker writes "Back in the dark ages of windows-based GUIs, corresponding to my own wandering VMS evangelical days, I became enamored of a series of books jauntily entitled Xxx Annoyances (from O'Reilly & Assocs.), where "Xxx" could be anything from "Windows 95", "Word", "Excel" or nearly piece of software which Microsoft produced. These were, if not the first, certainly among the most successful of the "tips & tricks" books that have become popular and useful to scads of hobbyists, ordinary users, hackers and, yes, even professionals in various IT pursuits. I was attracted, even a bit addicted, to these if only because they offered to try to make some useful sense out of the bewildering design choices, deficiencies and bugs that I'd find rampant in Windows and its application repertory. Then I found Keir Thomas, who has been writing about Linux for more than a decade. His new "tips" book entitled, Ubuntu Kung Fu — Tips & Tools for Exploring Using, and Tuning Linux, and published by Pragmatic Bookshelf, is wonderful. Having only recently wandered into the light of Linux, open source software, and Ubuntu in particular, this book comes as a welcome infusion to my addiction." Read below for the rest of Lorin's review. Ubuntu Kung Fu author Keir Thomas pages 367 publisher Pragmatic Bookshelf rating 9 reviewer Lorin Ricker ISBN 1-934356-22-0 summary A very useful "tips and tricks" how-to book about Ubuntu Linux As a relatively young Linux distro, Ubuntu already sports a wealth of introductory and how-to books vying for the enthusiast's money — and I've already purchased a significant sampling of these which informs my opinion about the book here under review. And even for Ubuntu, the "tips & tricks" section of my own Linux bookshelf contains volumes which run from the encyclopedic to the practical — I'd even collected O'Reilly's Ubuntu Hacks (Oxer, Rankin & Childers) well before encountering Ubuntu Kung Fu.
How well does Keir Thomas's new book fare in this crowded field? Does he provide actual unique value to the Ubuntu community, useful knowledge which is otherwise unavailable or hard to find? In a nutshell (oops, sorry... that's a book series for another time!): Yes, he does. In fact, he hits the target pretty squarely.
Ubuntu Kung Fu is organized as only three chapters (with no preface material at all): "1 Introduction," including obligatory "How to Read This Book," "Acknowledgments" and "Sharing" sections; "2 An Ubuntu Administration Crash Course"; and, the largest chapter by far, "3 The Tips" themselves.
Though it concentrates on rather basic material, the second chapter on Ubuntu administration is actually one of the best subject primers I've encountered so far, and is written directly and to-the-point. There's the right focus and enough detail to help those users making the initial transition from Windows to Linux/Ubuntu, including coaching on users and passwords, file system structure (see sidebar "Drive Letters and Ubuntu"), and guidance regarding "Command Line or GUI?".
For example, after weeks of my own stumbling about in the vast sea of information and opinion known as the Ubuntu Forums, searching in vain for a concise explanation on the distinction between a "virtual console" and a regular old "X-windows terminal" — as an old VMS hacker, I'd had experience with such things — I found exactly the explanation I needed, including Ctrl/Alt/F-key controls, in this chapter. The author manages to underline the relevance of this even to the novice Ubuntu user as it applies to "What do I do if things go wrong?", without getting mired in unneeded exotica.
This chapter continues with the necessary skills in software installation and management, including Synaptic and APT, packages and repositories, doing a good job of giving the novice his or her bearings to get started. It concludes with a decent orientation on config files and the gconf-editor, making and keeping backups, and what to do if it does all go wrong.
"The Tips," the third chapter, constitutes 315 separate items, covering over 300 pages, the big majority of the book. Each tip is clearly titled as to its purpose, and has a small check-box in the margin beside the title so that the reader has a place to mark the tip as to personal relevance and priority.
I suppose that the best way to give you a sense of the value of these tips is to provide a summary of my own "usage statistics", derived from my own check-box marks. When I first surveyed the book to get my own bearings, I used a yellow highlighter pen to color in the check-box for tips that caught my eye and that I especially wanted to get back to... Later, as I read through the entire "Tips" chapter, I made a check in the box for each tip I intended to return to for installation or implementation on my own Ubuntu box, and where appropriate, when I actually did install or implement the tip, I made an installation note as to time and details. A good many of the tips are for information or how-to skill only, with nothing to install or implement other than enhancing the reader's own understanding.
Of the 315 tips, I counted 108 (34%) that I marked with yellow highlight; 16 (5%) that I checked for implementation, but have not yet done so for one reason or another; and 19 (6%) that I've implemented on my system. Considering that any "tips & tricks" book ends up becoming a grab-bag of items with a hit-or-miss appeal to any particular person, this is a very good personal return-on-investment. Yet this breakdown is rather arbitrary, as many of the tips are techniques to know and use, rather than configurations to manage or applications to install. In other words, your mileage may vary.
Mr. Thomas's grab-bag is typical in its variety and scope — there's likely something for everyone, both Ubuntu novice and expert, in this book. And, true to style for such volumes, the author notes this about his "big book of tips": "...that you can jump in anywhere." This goes to the heart of my only notable criticism of the book, one of organization. Unlike many "tips" books, where there's usually some attempt to organize the presentation of topical items into a somewhat obvious order, the editorial decision for UKF was to explicitly order the tips randomly — this was no accident, as the author makes explicit in a couple of his remarks.
Indeed, reading through the "Tips" chapter in page-order is no different than embarking on a thorough reading in random order — there simply is no rhyme-or-reason to the presentation of items. This is particularly frustrating because there are numerous instances of tips which are closely related by subject or purpose, and for which the reader would be well served by having them grouped on successive pages for ease of reference and purpose.
That this was an editorial decision is made clear by the fact that the Table of Contents is itself 10 pages long, listing every single tip in the book, and is then followed by a secondary, equally lengthy "Contents by Topic" which attempts to group the tips by general category, "Application Enhancements", "Command Line Tricks", "General Productivity Tips", etc. Furthermore, the editorial effort was made to cross-reference related tips in the text, under Tip 39, we find "...see Tip 173, on page 204, and Tip 228, on page 260," and so on. For all this cross-referencing and contents by topic effort, wouldn't it have been more effective to simply organize the tips in a semblance of relationship, commonality and order? After all, having done a "Contents by Topic", why not just go ahead and organize the book accordingly?
For some readers, the random shuffling of tips may not matter much, as so much of the information will be newly encountered and of subjectively individual value. And value there is aplenty in this book! I'll close by noting four items which were of particular interest and value to me, things for which I'd been previously searching for without luck, or which I didn't even know existed in the open source world of resources:
First, on the ubiquitous implementation of yet another Trashcan for file deletion in a File Manager (the Gnome Nautilus app, which is prevalently used on Ubuntu): GUI designers just can't get over the fact that "mere mortals" might actually delete files and not really mean it... hence, the Trashcan mechanism to protect them from their own silly actions.
This is actually a two-edged sword, and I'd been caught in the quandary of having intended to really delete some application files, which happen to have been root-owned, only to have them get snagged in my file system's Trashcan. The real quandary commenced when, using sudo, I tried to figure out how to delete them from the command line — but where in the heck is "the Trashcan"? I could see the files in Nautilus (where I couldn't conveniently use sudo-power to delete them), but following my own hunches as to where-in-the-file-system the Trashcan was actually stored turned up empty-handed.
UKF to the rescue — see Tips 39, 228 and 309 for everything you'd need to know about handling the Trashcan from the command line.
Secondly, I'd become quite fond of enhanced cut-&-paste (multiple) clipboard capabilities under Windows. Again, UKF to the rescue: Tip 306 let me know of an open source (KDE) clipboard enhancement known as Klipper (it's in the Ubuntu Repositories), which scratches this itch most satisfactorily.
Third, although Ubuntu provides basic, rudimentary tools (Gnome and KDE) for capturing screen shots, until I got to Tip 313, I didn't know that the GIMP could be used to augment and sophisticate screen shot capturing! And, of course, you can refine, edit and save your shots in any GIMP-available format directly. A great enhancement, if only to my working GIMP knowledge!
Lastly, like most folks, I've got a dark side, secrets which must be kept — things like account numbers, passwords, and other personal arcana which cannot, or should not, be kept in unencrypted form. Again, under Windows, I'd found an encryption technology known as TrueCrypt which I'd employed (and paid for) on that platform for a couple of years prior — and with my transition to Linux, I had mistakenly assumed that I had to abandon TrueCrypt as a Windows-only app.
Imagine my surprise and delight when I encountered Tip 145, which informed me that TrueCrypt includes an open source licensed release for Linux, including exactly where to go to install it and how best to use it! Bravo, and thank you, Mr. Thomas, for helping me resurrect an old and trusted friend!
In summary, it should be apparent that, in spite of my grumblings about the random tip presentation, I think that Keir Thomas's Ubuntu Kung Fu is a wonderful book — address the organization issues in a second edition, and I think it'd become an exemplar of its type. I recommend it highly to anyone who has become, or is becoming, an Ubuntu Linux user and enthusiast. It usefully helps bridge the gap between the Microsoft Windows experience and the not-so-different world of the Linux desktop. It provides ample practical help and knowledge to advance your productive use of Ubuntu Linux. This book takes a pride-of-place position right beside my copy of Ubuntu Hacks, where I can refer to it whenever I've a hankering to implement "that new thing" I remember having read about.
You can purchase Ubuntu Kung Fu from amazon.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page. -
My Job Went To India
Josh Skillings writes "The author, Chad Fowler, draws upon his experiences as a software engineer, a team leader over a group of Indian developers, and as a jazz musician, to describe 52 ways or tips that will help you to become a more valuable employee. These tips are described in two or three pages each, and are usually illustrated by a practical example or story. The tips are well thought-out, well-explained and make sense. Chad draws upon the open source movement as well, highlighting ways that contributing to and learning from open source can improve your career. These tips gave me greater respect and appreciation for the open source movement in general." Read on for the rest of Josh's review. My Job Went To India (and All I Got was This Lousy Book) author Chad Fowler pages 185 publisher The Pragmatic Bookshelf rating 8 reviewer Josh Skillings ISBN 0-9766940-1-8 summary Offers 52 ways you can keep your software engineering job, or grow yourself into an even better job. Chad encourages the you to think of your career as life cycle of a product, and as such divides the 52 tips into the four areas of "Choosing Your Market", "Invest in your Product", "Execute", and "Market", and then two extra groups called, "Maintaining Your Edge", and "If you Can't Beat 'Em". This grouping works surprisingly well and provides an overarching context that makes sense. Many of the tips have specific calls to action at the end, which are useful if you don't already have ideas on how to apply the tip.
For example, under "Choosing Your Market", tip #7 "Don't Put Your Eggs In Someone Else's Basket", Chad encourages you to refrain from learning vendor-specific technologies that can disappear with the vendor, and then calls you to action by suggesting you write a small project in a technology that competes with the technology you are used to using. This will help you understand why the technology exists to start with and what opens your horizons for what might be coming next.
Under the section "Investing in your Product", tip #14 called "Practice, Practice, Practice", Chad offers suggestions on how software engineers can get even better by specific kinds of focused practice. The action items at the end of the section suggests practicing "Code Katas" katas similar to martial artists, but instead in code and in different languages.
With 52 tips, this book has a lot of tips, a tip for every week of the year, but you should expect to spend much longer than a week on most of them. A few of the tips you are probably doing already, but many of them you aren't. Some of the tips are fairly straight forward and easy to put in to practice. You could spend your entire life attempting and never achieve some of the other tips, such as tip #39, "Release Your Code." The ultimate goal of this tip is to be able to say in a job interview, "Oh, are you running Nifty++? I can help you with that- I wrote it." Chances are this scenario won't ever happen to you, but by working towards this goal in the ways the book outlines, you will definitely become a better, more valuable software engineer. Many of the tips will make you a better person in general, regardless of your career, such as tip #28, "Learn How To Fail", where Chad emphasizes how to fail gracefully and the rewards that can be learned from failure. This wide range of time, difficult, and application of the tips gives you something to work on today, next week, and next year.
The title of the book is silly. Yes, it was catchy enough for me to notice in the bookstore, with the red cover and the homeless (software engineer?) holding a sign, "Will Code For Food". So from that point of view, the cover worked. However, unless you've read the book, you might think it's as campy as the cover and wonder if it is somehow anti-Indian. I think a better title would be along the lines of "How to Get Any Job You Want", since if you can master all of these tips, you'll be the best there ever was.
While I didn't expect any specific technical advice, I would have liked some. I understand that an author needs to be sensitive to how fast technology changes, however just one tip with a warning: "This information is my opinion on April 11, 2007 and will probably change tomorrow". And then describes about how Subversion is a great tool, Python is a great language to learn, and learning design patterns can make your life easier, would have been appreciated. A tip like this would help you to understand the author a bit better and further encourage you to learn more.
If you want to improve yourself and you can accept advice, this book is for you. You will find things you can do better and skills you've never considered. Like some of the other Pragmatic Programmer books, I will never be able to master everything in this book, so I'll be reading this book again and again, trying to get better every time. Don't let the cover put you off, this is a great book.
You can purchase My Job Went To India (and All I Got was This Lousy Book) from amazon.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page. -
The State of the Scripting Universe
r.jimenezz writes "Via PragDave's blog I learned of an article by Lynn Greiner on the state of scripting languages, a.k.a. scripting dynamic languages. A number of influential personalities (Guido von Rossum, Damien Conway, PragDave himself and others) were interviewed and it's interesting to see how much their opinions coincide despite being interviewed separately. A lengthy but worthwhile reading." -
Pragmatic Project Automation
twelve71 (Alan Francis) writes "Apologies in advance for overuse of the word 'pragmatic,' but Dave Thomas and Andy Hunt together form a company called The Pragmatic Programmers, and published a book I'm sure many of you have read, titled The Pragmatic Programmer: from Journeyman to Master. The Pragmatic Programmer (or 'PragProg' as it is usually referred to) is a wonderful grab bag of 'good old common sense,' but its main strength (covering a very broad range of subjects) means that the authors have left a few holes around some important details. To plug some of these holes, and provide a good grounding for those just starting out, they have recently published 'The Pragmatic Starter Kit' - a set of books covering in detail some of the basics mentioned in PragProg." Read on for Alan's review of the latest book in the kit. Pragmatic Project Automation author Mike Clark pages http://www.pragmaticprogrammer.com/bookshelf/index.html publisher Pragmatic Bookshelf rating 9 reviewer Alan Francis ISBN 0974514039 summary Learn to use common, freely available tools to automate build, test, and release procedures.The first 2 (or possibly 3) books are Pragmatic Version Control with CVS and Pragmatic Unit Testing (which is available in Java and .NET flavours).
Pragmatic Project Automation is the latest book in the series and, interestingly, this book wasn't actually written by either Dave Thomas or Andy Hunt, but by Mike Clark (contributor to the 'Bitter EJB' book, editor of the JUnit FAQ, and responsible for the JUnitPerf and JDepend tools). Mike does a great job of ensuring this book fits in with the overall style of the other books in the series.
Up front, in case you're a "cut to the chase kind of guy," this book (and the others in the series) are must-haves and as a consultant with ThoughtWorks I'll have a set ready to distribute whenever I start working with a new client team.
Content The book helps the reader build a Java project slowly over the chapters, starting with a manual build-and-deploy process and automating a new aspect of it, chapter by chapter, until by the end of the book the software compiles, archives, deploys and configures itself multiple times a day. In addition, the build tools notify you of success or failure in a variety of interesting ways including email, SMS messages and different colored lava lamps.The first chapter provides a good introduction to the different types of automation available to projects. It also introduces the acronym 'CRISP' to help the reader remember the desirable characteristics of an ideal build process: Complete, Repeatable, Informative, Scheduled and Portable.
Chapter 2 gets you Repeatable by using ANT to bring together all the various steps you currently perform on your project into a single, one-click build. Chapter 3 works to turn the one-click build into a no-click build using tools as simple as cron as well as more complicated tools like the ANT scheduling tool CruiseControl. By the end of these two chapters your software can be compiling and testing itself automatically each time changes are checked into the version control system. But this is only the beginning.
Chapters 4 and 5 address the "Complete" and "Portable" portions of the CRISP model discussing how to include packaging, release management and deployment into your scheduled build. The last chapter addresses "Informative." How to monitor the build for success or failure, how to notify members of the project team using email, SMS, RSS or even the red and green Lava Lamps I mentioned above.
Summary This book, and the others in the series, provide a much needed set of manuals for getting a good set of basic practices up and running at the start of a project. Unlike the Unit Testing book, there's not a lot of programming in this one, but it's a worthwhile read for any programmer, regardless of experience level.Many people are becoming interested in eXtreme Programming and Agile methods for software development. These books help to support some of the key ideas of those methods - extensive unit testing and continuous integration.
The main flaw in the book doesn't affect its usefulness, only its readability. Of all the files used in the sample project, the only one covered in any detail is the build file. The source and manifest files that we're writing the ANT file to build are never discussed or described - we are left to guess at what the sample project might contain (unless we download the code from the website). While this didn't change what I was learning (how to manipulate the project files with ANT), I like to understand all the details and this omission did occasionally leave me a little irritated.
You can purchase Pragmatic Project Automation from bn.com. Slashdot welcomes readers' book reviews. To see your own review here, carefully read the book review guidelines, then visit the submission page. If you are interested in the Pragmatic Programmers, see also this interview linked earlier from Slashdot. -
Pragmatic Programmers on Designing with Metadata
Bill Venners writes "This week I've published the fourth installment of my interview with Andy Hunt and Dave Thomas, the authors of the best-selling book, The Pragmatic Programmer. In this installment, Dave and Andy talk about their recommended approach to design in which details are pulled out of the code and stored as metadata. This installment of the interview really made me think. Their focus on metadata sounded non-intuitive when I read their book, but in actually talking to them about it, I got the feeling they might be on to something. Check out: Abstraction and Detail."