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  • Recommended textbook for machine-level programming?

    - by Norman Ramsey
    I'm looking at textbooks for an undergraduate course in machine-level programming. If the perfect book existed, this is what it would look like: Uses examples written in C or assembly language, or both. Covers machine-level operations such as two's-complement integer arithmetic, bitwise operations, and floating-point arithmetic. Explains how caches work and how they affect performance. Explains machine instructions or assembly instructions. Bonus if the example assembly language includes x86; triple bonus if it includes x86-64 (aka AMD64). Explains how C values and data structures are represented using hardware registers and memory. Explains how C control structures are translated into assembly language using conditional and unconditional branch instructions. Explains something about procedure calling conventions and how procedure calls are implemented at the machine level. Books I might be interested in would probably have the words "machine organization" or "computer architecture" in the title. Here are some books I'm considering but am not quite happy with: Computer Systems: A Programmer's Perspective by Randy Bryant and Dave O'Hallaron. This is quite a nice book, but it's a book for a broad, shallow course in systems programming, and it contains a great deal of material my students don't need. Also, it is just out in a second edition, which will make it expensive. Computer Organization and Design: The Hardware/Software Interface by Dave Patterson and John Hennessy. This is also a very nice book, but it contains way more information about how the hardware works than my students need. Also, the exercises look boring. Finally, it has a show-stopping bug: it is based very heavily on MIPS hardware and the use of a MIPS simulator. My students need to learn how to use DDD, and I can't see getting this to work on a simulator. Not to mention that I can't see them cross-compiling their code for the simulator, and so on and so forth. Another flaw is that the book mentions the x86 architecture only to sneer at it. I am entirely sympathetic to this point of view, but news flash! You guys lost! Write Great Code Vol I: Understanding the Machine by Randall Hyde. I haven't evaluated this book as thoroughly as the other two. It has a lot of what I need, but the translation from high-level language to assembler is deferred to Volume Two, which has mixed reviews. My students will be annoyed if I make them buy a two-volume series, even if the price of those two volumes is smaller than the price of other books. I would really welcome other suggestions of books that would help students in a class where they are to learn how C-language data structures and code are translated to machine-level data structures and code and where they learn how to think about performance, with an emphasis on the cache.

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  • Null Values And The T-SQL IN Operator

    - by Jesse
    I came across some unexpected behavior while troubleshooting a failing test the other day that took me long enough to figure out that I thought it was worth sharing here. I finally traced the failing test back to a SELECT statement in a stored procedure that was using the IN t-sql operator to exclude a certain set of values. Here’s a very simple example table to illustrate the issue: Customers CustomerId INT, NOT NULL, Primary Key CustomerName nvarchar(100) NOT NULL SalesRegionId INT NULL   The ‘SalesRegionId’ column contains a number representing the sales region that the customer belongs to. This column is nullable because new customers get created all the time but assigning them to sales regions is a process that is handled by a regional manager on a periodic basis. For the purposes of this example, the Customers table currently has the following rows: CustomerId CustomerName SalesRegionId 1 Customer A 1 2 Customer B NULL 3 Customer C 4 4 Customer D 2 5 Customer E 3   How could we write a query against this table for all customers that are NOT in sales regions 2 or 4? You might try something like this: 1: SELECT 2: CustomerId, 3: CustomerName, 4: SalesRegionId 5: FROM Customers 6: WHERE SalesRegionId NOT IN (2,4)   Will this work? In short, no; at least not in the way that you might expect. Here’s what this query will return given the example data we’re working with: CustomerId CustomerName SalesRegionId 1 Customer A 1 5 Customer E 5   I was expecting that this query would also return ‘Customer B’, since that customer has a NULL SalesRegionId. In my mind, having a customer with no sales region should be included in a set of customers that are not in sales regions 2 or 4.When I first started troubleshooting my issue I made note of the fact that this query should probably be re-written without the NOT IN clause, but I didn’t suspect that the NOT IN clause was actually the source of the issue. This particular query was only one minor piece in a much larger process that was being exercised via an automated integration test and I simply made a poor assumption that the NOT IN would work the way that I thought it should. So why doesn’t this work the way that I thought it should? From the MSDN documentation on the t-sql IN operator: If the value of test_expression is equal to any value returned by subquery or is equal to any expression from the comma-separated list, the result value is TRUE; otherwise, the result value is FALSE. Using NOT IN negates the subquery value or expression. The key phrase out of that quote is, “… is equal to any expression from the comma-separated list…”. The NULL SalesRegionId isn’t included in the NOT IN because of how NULL values are handled in equality comparisons. From the MSDN documentation on ANSI_NULLS: The SQL-92 standard requires that an equals (=) or not equal to (<>) comparison against a null value evaluates to FALSE. When SET ANSI_NULLS is ON, a SELECT statement using WHERE column_name = NULL returns zero rows even if there are null values in column_name. A SELECT statement using WHERE column_name <> NULL returns zero rows even if there are nonnull values in column_name. In fact, the MSDN documentation on the IN operator includes the following blurb about using NULL values in IN sub-queries or expressions that are used with the IN operator: Any null values returned by subquery or expression that are compared to test_expression using IN or NOT IN return UNKNOWN. Using null values in together with IN or NOT IN can produce unexpected results. If I were to include a ‘SET ANSI_NULLS OFF’ command right above my SELECT statement I would get ‘Customer B’ returned in the results, but that’s definitely not the right way to deal with this. We could re-write the query to explicitly include the NULL value in the WHERE clause: 1: SELECT 2: CustomerId, 3: CustomerName, 4: SalesRegionId 5: FROM Customers 6: WHERE (SalesRegionId NOT IN (2,4) OR SalesRegionId IS NULL)   This query works and properly includes ‘Customer B’ in the results, but I ultimately opted to re-write the query using a LEFT OUTER JOIN against a table variable containing all of the values that I wanted to exclude because, in my case, there could potentially be several hundred values to be excluded. If we were to apply the same refactoring to our simple sales region example we’d end up with: 1: DECLARE @regionsToIgnore TABLE (IgnoredRegionId INT) 2: INSERT @regionsToIgnore values (2),(4) 3:  4: SELECT 5: c.CustomerId, 6: c.CustomerName, 7: c.SalesRegionId 8: FROM Customers c 9: LEFT OUTER JOIN @regionsToIgnore r ON r.IgnoredRegionId = c.SalesRegionId 10: WHERE r.IgnoredRegionId IS NULL By performing a LEFT OUTER JOIN from Customers to the @regionsToIgnore table variable we can simply exclude any rows where the IgnoredRegionId is null, as those represent customers that DO NOT appear in the ignored regions list. This approach will likely perform better if the number of sales regions to ignore gets very large and it also will correctly include any customers that do not yet have a sales region.

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  • C++11 support for higher-order list functions

    - by Giorgio
    Most functional programming languages (e.g. Common Lisp, Scheme / Racket, Clojure, Haskell, Scala, Ocaml, SML) support some common higher-order functions on lists, such as map, filter, takeWhile, dropWhile, foldl, foldr (see e.g. Common Lisp, Scheme / Racket, Clojure side-by-side reference sheet, the Haskell, Scala, OCaml, and the SML documentation.) Does C++11 have equivalent standard methods or functions on lists? For example, consider the following Haskell snippet: let xs = [1, 2, 3, 4, 5] let ys = map (\x -> x * x) xs How can I express the second expression in modern standard C++? std::list<int> xs = ... // Initialize the list in some way. std::list<int> ys = ??? // How to translate the Haskell expression? What about the other higher-order functions mentioned above? Can they be directly expressed in C++?

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  • Drupal incorrectly escapes tags in javascript

    - by sergdev
    I installed drupal-6.16. I applied the patch from the post http://drupal.org/node/222926#comment-930745. It works correctly in simple cases. But following code of counter is handled incorrectly and counter is now displayed on the page after drupal. Drupal modifies the string "alt='1Gb.ua counter' /><\/a>")</a></script> to "alt='1Gb.ua counter' />&lt;\/a>")</a></script> The full code of counter follows: <br><br> Text <br><br> <!-- counter.1Gb.ua --> <script language="javascript" type="text/javascript"> cgb_js="1.0"; cgb_r=""+Math.random()+"&r="+ escape(document.referrer)+"&pg="+ escape(window.location.href); document.cookie="rqbct=1; path=/"; cgb_r+="&c="+ (document.cookie?"Y":"N"); </script><script language="javascript1.1" type="text/javascript"> cgb_js="1.1";cgb_r+="&j="+ (navigator.javaEnabled()?"Y":"N")</script> <script language="javascript1.2" type="text/javascript"> cgb_js="1.2"; cgb_r+="&wh="+screen.width+ 'x'+screen.height+"&px="+ (((navigator.appName.substring(0,3)=="Mic"))? screen.colorDepth:screen.pixelDepth)</script> <script language="javascript1.3" type="text/javascript"> cgb_js="1.3"</script> <script language="javascript" type="text/javascript">cgb_r+="&js="+cgb_js; document.write("<a href='http://www.1Gb.ua?cnt=1416'>"+ "<img src='http://counter.1Gb.ua/cnt.aspx?"+ "u=1416&"+cgb_r+ "&' border=0 width=88 height=31 "+ "alt='1Gb.ua counter'><\/a>")</script> <noscript><a href='http://www.1Gb.ua?cnt=1416'> <img src="http://counter.1Gb.ua/cnt.aspx?u=1416" border=0 width="88" height="31" alt="1Gb.ua counter"></a> </noscript> <!-- /counter.1Gb.ua --> Does anybody have this code working? How can it be fixed? Thanks a lot in advance!

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  • How can I modify my Shunting-Yard Algorithm so it accepts unary operators?

    - by KingNestor
    I've been working on implementing the Shunting-Yard Algorithm in JavaScript for class. Here is my work so far: var userInput = prompt("Enter in a mathematical expression:"); var postFix = InfixToPostfix(userInput); var result = EvaluateExpression(postFix); document.write("Infix: " + userInput + "<br/>"); document.write("Postfix (RPN): " + postFix + "<br/>"); document.write("Result: " + result + "<br/>"); function EvaluateExpression(expression) { var tokens = expression.split(/([0-9]+|[*+-\/()])/); var evalStack = []; while (tokens.length != 0) { var currentToken = tokens.shift(); if (isNumber(currentToken)) { evalStack.push(currentToken); } else if (isOperator(currentToken)) { var operand1 = evalStack.pop(); var operand2 = evalStack.pop(); var result = PerformOperation(parseInt(operand1), parseInt(operand2), currentToken); evalStack.push(result); } } return evalStack.pop(); } function PerformOperation(operand1, operand2, operator) { switch(operator) { case '+': return operand1 + operand2; case '-': return operand1 - operand2; case '*': return operand1 * operand2; case '/': return operand1 / operand2; default: return; } } function InfixToPostfix(expression) { var tokens = expression.split(/([0-9]+|[*+-\/()])/); var outputQueue = []; var operatorStack = []; while (tokens.length != 0) { var currentToken = tokens.shift(); if (isNumber(currentToken)) { outputQueue.push(currentToken); } else if (isOperator(currentToken)) { while ((getAssociativity(currentToken) == 'left' && getPrecedence(currentToken) <= getPrecedence(operatorStack[operatorStack.length-1])) || (getAssociativity(currentToken) == 'right' && getPrecedence(currentToken) < getPrecedence(operatorStack[operatorStack.length-1]))) { outputQueue.push(operatorStack.pop()) } operatorStack.push(currentToken); } else if (currentToken == '(') { operatorStack.push(currentToken); } else if (currentToken == ')') { while (operatorStack[operatorStack.length-1] != '(') { if (operatorStack.length == 0) throw("Parenthesis balancing error! Shame on you!"); outputQueue.push(operatorStack.pop()); } operatorStack.pop(); } } while (operatorStack.length != 0) { if (!operatorStack[operatorStack.length-1].match(/([()])/)) outputQueue.push(operatorStack.pop()); else throw("Parenthesis balancing error! Shame on you!"); } return outputQueue.join(" "); } function isOperator(token) { if (!token.match(/([*+-\/])/)) return false; else return true; } function isNumber(token) { if (!token.match(/([0-9]+)/)) return false; else return true; } function getPrecedence(token) { switch (token) { case '^': return 9; case '*': case '/': case '%': return 8; case '+': case '-': return 6; default: return -1; } } function getAssociativity(token) { switch(token) { case '+': case '-': case '*': case '/': return 'left'; case '^': return 'right'; } } It works fine so far. If I give it: ((5+3) * 8) It will output: Infix: ((5+3) * 8) Postfix (RPN): 5 3 + 8 * Result: 64 However, I'm struggling with implementing the unary operators so I could do something like: ((-5+3) * 8) What would be the best way to implement unary operators (negation, etc)? Also, does anyone have any suggestions for handling floating point numbers as well? One last thing, if anyone sees me doing anything weird in JavaScript let me know. This is my first JavaScript program and I'm not used to it yet.

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  • Drupal incorrectly espaces tags in javascript

    - by sergdev
    I installed drupal-6.16. I applied the patch from the post http://drupal.org/node/222926#comment-930745. It works correctly in simple cases. But for following code for counter is handled incorrectly: <br><br> Text <br><br> <!-- counter.1Gb.ua --> <script language="javascript" type="text/javascript"> cgb_js="1.0"; cgb_r=""+Math.random()+"&r="+ escape(document.referrer)+"&pg="+ escape(window.location.href); document.cookie="rqbct=1; path=/"; cgb_r+="&c="+ (document.cookie?"Y":"N"); </script><script language="javascript1.1" type="text/javascript"> cgb_js="1.1";cgb_r+="&j="+ (navigator.javaEnabled()?"Y":"N")</script> <script language="javascript1.2" type="text/javascript"> cgb_js="1.2"; cgb_r+="&wh="+screen.width+ 'x'+screen.height+"&px="+ (((navigator.appName.substring(0,3)=="Mic"))? screen.colorDepth:screen.pixelDepth)</script> <script language="javascript1.3" type="text/javascript"> cgb_js="1.3"</script> <script language="javascript" type="text/javascript">cgb_r+="&js="+cgb_js; document.write("<a href='http://www.1Gb.ua?cnt=1416'>"+ "<img src='http://counter.1Gb.ua/cnt.aspx?"+ "u=1416&"+cgb_r+ "&' border=0 width=88 height=31 "+ "alt='1Gb.ua counter'><\/a>")</script> <noscript><a href='http://www.1Gb.ua?cnt=1416'> <img src="http://counter.1Gb.ua/cnt.aspx?u=1416" border=0 width="88" height="31" alt="1Gb.ua counter"></a> </noscript> <!-- /counter.1Gb.ua --> It modifies the string "alt='1Gb.ua counter' /><\/a>")</a></script> to "alt='1Gb.ua counter' />&lt;\/a>")</a></script> Does anybody have this code working? If so how this can be fixed? Thanks a lot in advance!

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  • Happy New Year!! Microsoft MVP Award

    - by T
    I received this letter  from Microsoft this morning   Dear Teresa Burger, Congratulations! We are pleased to present you with the 2011 Microsoft® MVP Award! This award is given to exceptional technical community leaders who actively share their high quality, real world expertise with others. We appreciate your outstanding contributions in Expression Blend technical communities during the past year. There has been some work involved but over all, 2010 has been a blast!!  I am very honored to have received this award and look forward to a lot more community involvement, learning, exploring and sharing in the years to come.  You all rock!! Thank you!!!  http://mvp.support.microsoft.com/ http://www.microsoft.com/expression/products/Blend_Overview.aspx

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  • Exceptions confusion

    - by Misiur
    Hi there. I'm trying to build site using OOP in PHP. Everyone is talking about Singleton, hermetization, MVC, and using exceptions. So I've tried to do it like this: Class building whole site: class Core { public $is_core; public $theme; private $db; public $language; private $info; static private $instance; public function __construct($lang = 'eng', $theme = 'default') { if(!self::$instance) { try { $this->db = new sdb(DB_TYPE.':host='.DB_HOST.';dbname='.DB_NAME, DB_USER, DB_PASS); } catch(PDOException $e) { throw new CoreException($e->getMessage()); } try { $this->language = new Language($lang); } catch(LangException $e) { throw new CoreException($e->getMessage()); } try { $this->theme = new Theme($theme); } catch(ThemeException $e) { throw new CoreException($e->getMessage()); } } return self::$instance; } public function getSite($what) { return $this->language->getLang(); } private function __clone() { } } Class managing themes class Theme { private $theme; public function __construct($name = 'default') { if(!is_dir("themes/$name")) { throw new ThemeException("Unable to load theme $name"); } else { $this->theme = $name; } } public function getTheme() { return $this->theme; } public function display($part) { if(!is_file("themes/$this->theme/$part.php")) { throw new ThemeException("Unable to load theme part: themes/$this->theme/$part.php"); } else { return 'So far so good'; } } } And usage: error_reporting(E_ALL); require_once('config.php'); require_once('functions.php'); try { $core = new Core(); } catch(CoreException $e) { echo 'Core Exception: '.$e->getMessage(); } echo $core->theme->getTheme(); echo "<br />"; echo $core->language->getLang(); try { $core->theme->display('footer'); } catch(ThemeException $e) { echo $e->getMessage(); } I don't like those exception handlers - i don't want to catch them like some pokemons... I want to use things simple: $core-theme-display('footer'); And if something is wrong, and debug mode is enabled, then aplication show error. What should i do?

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  • Adaptive Connections For ADFBC

    - by Duncan Mills
    Some time ago I wrote an article on Adaptive Bindings showing how the pageDef for a an ADF UI does not have to be wedded to a fixed data control or collection / View Object. This article has proved pretty popular, so as a follow up I wanted to cover another "Adaptive" feature of your ADF applications, the ability to make multiple different connections from an Application Module, at runtime. Now, I'm sure you'll be aware that if you define your application to use a data-source rather than a hard-coded JDBC connection string, then you have the ability to change the target of that data-source after deployment to point to a different database. So that's great, but the reality of that is that this single connection is effectively fixed within the application right?  Well no, this it turns out is a common misconception. To be clear, yes a single instance of an ADF Application Module is associated with a single connection but there is nothing to stop you from creating multiple instances of the same Application Module within the application, all pointing at different connections.  If fact this has been possible for a long time using a custom extension point with code that which extends oracle.jbo.http.HttpSessionCookieFactory. This approach, however, involves writing code and no-one likes to write any more code than they need to, so, is there an easier way? Yes indeed.  It is in fact  a little publicized feature that's available in all versions of 11g, the ELEnvInfoProvider. What Does it Do?  The ELEnvInfoProvider  is  a pre-existing class (the full path is  oracle.jbo.client.ELEnvInfoProvider) which you can plug into your ApplicationModule configuration using the jbo.envinfoprovider property. Visuallty you can set this in the editor, or you can also set it directly in the bc4j.xcfg (see below for an example) . Once you have plugged in this envinfoprovider, here's the fun bit, rather than defining the hard-coded name of a datasource instead you can plug in a EL expression for the connection to use.  So what's the benefit of that? Well it allows you to defer the selection of a connection until the point in time that you instantiate the AM. To define the expression itself you'll need to do a couple of things: First of all you'll need a managed bean of some sort – e.g. a sessionScoped bean defined in your ViewController project. This will need a getter method that returns the name of the connection. Now this connection itself needs to be defined in your Application Server, and can be managed through Enterprise Manager, WLST or through MBeans. (You may need to read the documentation [http://docs.oracle.com/cd/E28280_01/web.1111/b31974/deployment_topics.htm#CHDJGBDD] here on how to configure connections at runtime if you're not familiar with this)   The EL expression (e.g. ${connectionManager.connection} is then defined in the configuration by editing the bc4j.xcfg file (there is a hyperlink directly to this file on the configuration editing screen in the Application Module editor). You simply replace the hardcoded JDBCName value with the expression.  So your cfg file would end up looking something like this (notice the reference to the ELEnvInfoProvider that I talked about earlier) <BC4JConfig version="11.1" xmlns="http://xmlns.oracle.com/bc4j/configuration">   <AppModuleConfigBag ApplicationName="oracle.demo.model.TargetAppModule">   <AppModuleConfig DeployPlatform="LOCAL"  JDBCName="${connectionManager.connection}" jbo.project="oracle.demo.model.Model" name="TargetAppModuleLocal" ApplicationName="oracle.demo.model.TargetAppModule"> <AM-Pooling jbo.doconnectionpooling="true"/> <Database jbo.locking.mode="optimistic">       <Security AppModuleJndiName="oracle.demo.model.TargetAppModule"/>    <Custom jbo.envinfoprovider="oracle.jbo.client.ELEnvInfoProvider"/> </AppModuleConfig> </AppModuleConfigBag> </BC4JConfig> Still Don't Quite Get It? So far you might be thinking, well that's fine but what difference does it make if the connection is resolved "just in time" rather than up front and changed as required through Enterprise Manager? Well a trivial example would be where you have a single application deployed to your application server, but for different users you want to connect to different databases. Because, the evaluation of the connection is deferred until you first reference the AM you have a decision point that can take the user identity into account. However, think about it for a second.  Under what circumstances does a new AM get instantiated? Well at the first reference of the AM within the application yes, but also whenever a Task Flow is entered -  if the data control scope for the Task Flow is ISOLATED.  So the reality is, that on a single screen you can embed multiple Task Flows, all of which are pointing at different database connections concurrently. Hopefully you'll find this feature useful, let me know... 

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  • Hosted News Carousel

    - by user19240
    I'm trying to add a news carousel on my OneHub site. I know there are quite a few plugins that I can use, but I'm looking for a ready-to-use hosted solution where people can log-on and manage the content, and I can simply include as an iFrame widget on our OneHub site. We would prefer to use Expression Engine, since we're using this on some of our other websites. It looks like Expression Engine + JQuery Cycle Rotator might be an option, not sure how easily I can get this onto OneHub though... WordPress has a carousel plugin as well that I'll explore. Anyhow, while I'm trying out these options, I figured I would put a question out there for any thoughts or advice, other solutions, etc. Any help would be greatly appreciated! Thanks, Alan

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  • How to localize numerals?

    - by SoLoGHoST
    Ok, I'm using mathematical equations to output numbers, though, I need this to be compatible for all languages. Currently, all language strings are within a php array called $txt, and each key of the array gets called for that language. I'm outputting the following: Column 1, Column 2, Column 3, and so on, as well as Row 1, Row 2, Row 3, and so on. The calculations are done via php and javascript, so I'm wondering on the best approach for how to support all languages for the numbers only. I don't do the translations, someone else does, but I need to be able to point it to, either the php variable $txt of where the language is defined, or, since the calculations are done via javascript also, I need to somehow store this in there. I'm thinking of storing something like this: // This part goes in the php language file. $txt['0'] = '0'; $txt['1'] = '1'; $txt['2'] = '2'; $txt['2'] = '3'; $txt['4'] = '4'; $txt['5'] = '5'; $txt['6'] = '6'; $txt['7'] = '7'; $txt['8'] = '8'; $txt['9'] = '9'; // This part goes in the php file that needs to call the numbers. echo '<script> var numtxts = new Array(); numtxts[0] = \'', $txt['0'], '\'; numtxts[1] = \'', $txt['1'], '\'; numtxts[2] = \'', $txt['2'], '\'; numtxts[3] = \'', $txt['3'], '\'; numtxts[4] = \'', $txt['4'], '\'; numtxts[5] = \'', $txt['5'], '\'; numtxts[6] = \'', $txt['6'], '\'; numtxts[7] = \'', $txt['7'], '\'; numtxts[8] = \'', $txt['8'], '\'; numtxts[9] = \'', $txt['9'], '\'; </script>'; And than in the javascript function it could grab the correct string for each number like so: // Example Number String below. var numString = "10"; var transNum = ""; for(x=0;x<numString.length;x++) { var numChar = numString.charAt(x); transNum += numtxts[parseInt(numChar)]; } return transNum; The problem with this bit of code is that it groups the numbers, not sure if all languages do that, like the english language does...? Perhaps there's a better approach for this? Can anyone help please? Thanks :)

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  • JavaFX in a JSF 2.0 Custom Tag?

    - by Geertjan
    I followed these instructions and now have a simple JSF 2.0 tag handler: The reason I created this is because I'm curious about whether it would be possible to change the tag created above: <my:hello name="Jack" /> ...to something like this: <my:chart type="pie" xAxis="${some-expression}" yAxis="${some-expression}" width="300" height="500" /> Has anyone tried this? That could be a way to incorporate a JavaFX chart into a Java EE application. That's different to how Adam Bien is doing it in LightFish, but might be a simpler and more reusable way of doing the same thing.

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  • Generic IEqualityComparer

    - by Nettuce
    A generic equality comparer that takes a property expression or a comparison Func public class GenericComparer<T> : IEqualityComparer<T> where T : class         {             private readonly Func<T, T, bool> comparerExpression;             private readonly string propertyName;             public GenericComparer(Func<T, T, bool> comparerExpression)             {                 this.comparerExpression = comparerExpression;             }             public GenericComparer(Expression<Func<T, object>> propertyExpression)             {                 propertyName = (propertyExpression.Body is UnaryExpression ? (MemberExpression)((UnaryExpression)propertyExpression.Body).Operand : (MemberExpression)propertyExpression.Body).Member.Name;             }             public bool Equals(T x, T y)             {                 return comparerExpression == null ? x.GetType().GetProperty(propertyName).GetValue(x, null).Equals(y.GetType().GetProperty(propertyName).GetValue(y, null)) : comparerExpression.Invoke(x, y);             }             public int GetHashCode(T obj)             {                 return obj.ToString().GetHashCode();             }         }

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  • Boost Spirit and Lex parser problem

    - by bpw1621
    I've been struggling to try and (incrementally) modify example code from the documentation but with not much different I am not getting the behavior I expect. Specifically, the "if" statement fails when (my intent is that) it should be passing (there was an "else" but that part of the parser was removed during debugging). The assignment statement works fine. I had a "while" statement as well which had the same problem as the "if" statement so I am sure if I can get help to figure out why one is not working it should be easy to get the other going. It must be kind of subtle because this is almost verbatim what is in one of the examples. #include <iostream> #include <fstream> #include <string> #define BOOST_SPIRIT_DEBUG #include <boost/config/warning_disable.hpp> #include <boost/spirit/include/qi.hpp> #include <boost/spirit/include/lex_lexertl.hpp> #include <boost/spirit/include/phoenix_operator.hpp> #include <boost/spirit/include/phoenix_statement.hpp> #include <boost/spirit/include/phoenix_container.hpp> namespace qi = boost::spirit::qi; namespace lex = boost::spirit::lex; inline std::string read_from_file( const char* infile ) { std::ifstream instream( infile ); if( !instream.is_open() ) { std::cerr << "Could not open file: \"" << infile << "\"" << std::endl; exit( -1 ); } instream.unsetf( std::ios::skipws ); return( std::string( std::istreambuf_iterator< char >( instream.rdbuf() ), std::istreambuf_iterator< char >() ) ); } template< typename Lexer > struct LangLexer : lex::lexer< Lexer > { LangLexer() { identifier = "[a-zA-Z][a-zA-Z0-9_]*"; number = "[-+]?(\\d*\\.)?\\d+([eE][-+]?\\d+)?"; if_ = "if"; else_ = "else"; this->self = lex::token_def<> ( '(' ) | ')' | '{' | '}' | '=' | ';'; this->self += identifier | number | if_ | else_; this->self( "WS" ) = lex::token_def<>( "[ \\t\\n]+" ); } lex::token_def<> if_, else_; lex::token_def< std::string > identifier; lex::token_def< double > number; }; template< typename Iterator, typename Lexer > struct LangGrammar : qi::grammar< Iterator, qi::in_state_skipper< Lexer > > { template< typename TokenDef > LangGrammar( const TokenDef& tok ) : LangGrammar::base_type( program ) { using boost::phoenix::val; using boost::phoenix::ref; using boost::phoenix::size; program = +block; block = '{' >> *statement >> '}'; statement = assignment | if_stmt; assignment = ( tok.identifier >> '=' >> expression >> ';' ); if_stmt = ( tok.if_ >> '(' >> expression >> ')' >> block ); expression = ( tok.identifier[ qi::_val = qi::_1 ] | tok.number[ qi::_val = qi::_1 ] ); BOOST_SPIRIT_DEBUG_NODE( program ); BOOST_SPIRIT_DEBUG_NODE( block ); BOOST_SPIRIT_DEBUG_NODE( statement ); BOOST_SPIRIT_DEBUG_NODE( assignment ); BOOST_SPIRIT_DEBUG_NODE( if_stmt ); BOOST_SPIRIT_DEBUG_NODE( expression ); } qi::rule< Iterator, qi::in_state_skipper< Lexer > > program, block, statement; qi::rule< Iterator, qi::in_state_skipper< Lexer > > assignment, if_stmt; typedef boost::variant< double, std::string > expression_type; qi::rule< Iterator, expression_type(), qi::in_state_skipper< Lexer > > expression; }; int main( int argc, char** argv ) { typedef std::string::iterator base_iterator_type; typedef lex::lexertl::token< base_iterator_type, boost::mpl::vector< double, std::string > > token_type; typedef lex::lexertl::lexer< token_type > lexer_type; typedef LangLexer< lexer_type > LangLexer; typedef LangLexer::iterator_type iterator_type; typedef LangGrammar< iterator_type, LangLexer::lexer_def > LangGrammar; LangLexer lexer; LangGrammar grammar( lexer ); std::string str( read_from_file( 1 == argc ? "boostLexTest.dat" : argv[1] ) ); base_iterator_type strBegin = str.begin(); iterator_type tokenItor = lexer.begin( strBegin, str.end() ); iterator_type tokenItorEnd = lexer.end(); std::cout << std::setfill( '*' ) << std::setw(20) << '*' << std::endl << str << std::endl << std::setfill( '*' ) << std::setw(20) << '*' << std::endl; bool result = qi::phrase_parse( tokenItor, tokenItorEnd, grammar, qi::in_state( "WS" )[ lexer.self ] ); if( result ) { std::cout << "Parsing successful" << std::endl; } else { std::cout << "Parsing error" << std::endl; } return( 0 ); } Here is the output of running this (the file read into the string is dumped out first in main) ******************** { a = 5; if( a ){ b = 2; } } ******************** <program> <try>{</try> <block> <try>{</try> <statement> <try></try> <assignment> <try></try> <expression> <try></try> <success>;</success> <attributes>(5)</attributes> </expression> <success></success> <attributes>()</attributes> </assignment> <success></success> <attributes>()</attributes> </statement> <statement> <try></try> <assignment> <try></try> <fail/> </assignment> <if_stmt> <try> if(</try> <fail/> </if_stmt> <fail/> </statement> <fail/> </block> <fail/> </program> Parsing error

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  • SQLAuthority News – Tips for Traveling to Nepal

    - by pinaldave
    If you are a regular reader of this blog, you might know that I travel nearly 20+ days out of 30 days in a month. There are cases when I don’t have a chance to go home for an entire month and my family has to travel to different cities just to meet me. During my recent visit, one of my acquaintances suggested that I should blog about my travel experiences as well. This can be helpful to others who are traveling to the country or city. I have previously written about my experience about all the airlines in India. I would be writing about a few tips about traveling to the beautiful country Nepal today. Kathmandu, the capital of Nepal is very scenic. There are lots of historical places to see and visit. I was fortunate enough to stopover the Pashupatinath Temple, Bhaktapur, Vasantpur and the temple of Kumari Goddess. I also visited casinos there, but even if  I have stayed in Las Vegas for 3 and a half years before, I was not keen on them so I left the casinos just like what I did in Las Vegas . I also traveled to the famous Thamel area by car. Here are my quick tips for anyone who is planning to visit Nepal. They are not categorized but just written in the order that came to my mind. Please note that if you are an Indian, you will get a special privilege everywhere in Nepal, beginning right from the Indian airports. Use the expression “Nameste!” If you want to greet any Indian or Nepali. Indian Nationals do not need visa/passport to enter Nepal. In fact, Indian Nationals can just walk in to Nepal without any passport; but should have any valid Indian ID. There is no use of a passport since it will not be stamped at any immigration ports, whether in India or Nepal. Indian currency is widely accepted everywhere. However, please bring only Rs. 100 bills/notes as Rs. 500 or Rs. 1000 are not accepted. However, casinos there will accept larger bills. Indian National Language – Hindi is widely spoken and understood everywhere. I did not find a single person who had trouble speaking it. Nepali language uses the scripting language as Devnagari, which is similar to Hindi. Here, you will find food of almost every country.  The taste of Nepali food is authentic and very delicious. It is very safe to travel and move around in Kathmandu (despite what media suggests). However, it will really help if you have a friend who speaks Nepali. You can negotiate a few deals and cut off to almost 1/5 of the original quoted price of products sold here. If you are from Gujarat, India – you will find Nepali language sharing many common words. Temples are everywhere, so do not miss to visit a few of them. Pashupatinath is a must. Only followers of Hindu religion (from Nepal and India only) are allowed in most of the holy places. Camera is allowed everywhere except on the holy places. Now it is your turn to share your opinions or any suggestions. I think Nepal is a great country as there are lots of places to visit. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, T SQL, Technology

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  • NDepend tool – Why every developer working with Visual Studio.NET must try it!

    - by hajan
    In the past two months, I have had a chance to test the capabilities and features of the amazing NDepend tool designed to help you make your .NET code better, more beautiful and achieve high code quality. In other words, this tool will definitely help you harmonize your code. I mean, you’ve probably heard about Chaos Theory. Experienced developers and architects are already advocates of the programming chaos that happens when working with complex project architecture, the matrix of relationships between objects which simply even if you are the one who have written all that code, you know how hard is to visualize everything what does the code do. When the application get more and more complex, you will start missing a lot of details in your code… NDepend will help you visualize all the details on a clever way that will help you make smart moves to make your code better. The NDepend tool supports many features, such as: Code Query Language – which will help you write custom rules and query your own code! Imagine, you want to find all your methods which have more than 100 lines of code :)! That’s something simple! However, I will dig much deeper in one of my next blogs which I’m going to dedicate to the NDepend’s CQL (Code Query Language) Architecture Visualization – You are an architect and want to visualize your application’s architecture? I’m thinking how many architects will be really surprised from their architectures since NDepend shows your whole architecture showing each piece of it. NDepend will show you how your code is structured. It shows the architecture in graphs, but if you have very complex architecture, you can see it in Dependency Matrix which is more suited to display large architecture Code Metrics – Using NDepend’s panel, you can see the code base according to Code Metrics. You can do some additional filtering, like selecting the top code elements ordered by their current code metric value. You can use the CQL language for this purpose too. Smart Search – NDepend has great searching ability, which is again based on the CQL (Code Query Language). However, you have some options to search using dropdown lists and text boxes and it will generate the appropriate CQL code on fly. Moreover, you can modify the CQL code if you want it to fit some more advanced searching tasks. Compare Builds and Code Difference – NDepend will also help you compare previous versions of your code with the current one at one of the most clever ways I’ve seen till now. Create Custom Rules – using CQL you can create custom rules and let NDepend warn you on each build if you break a rule Reporting – NDepend can automatically generate reports with detailed stats, graph representation, dependency matrixes and some additional advanced reporting features that will simply explain you everything related to your application’s code, architecture and what you’ve done. And that’s not all. As I’ve seen, there are many other features that NDepend supports. I will dig more in the upcoming days and will blog more about it. The team who built the NDepend have also created good documentation, which you can find on the NDepend website. On their website, you can also find some good videos that will help you get started quite fast. It’s easy to install and what is very important it is fully integrated with Visual Studio. To get you started, you can watch the following Getting Started Online Demo and Tutorial with explanations and screenshots. If you are interested to know more about how to use the features of this tool, either visit their website or wait for my next blogs where I will show some real examples of using the tool and how it helps make your code better. And the last thing for this blog, I would like to copy one sentence from the NDepend’s home page which says: ‘Hence the software design becomes concrete, code reviews are effective, large refactoring are easy and evolution is mastered.’ Website: www.ndepend.com Getting Started: http://www.ndepend.com/GettingStarted.aspx Features: http://www.ndepend.com/Features.aspx Download: http://www.ndepend.com/NDependDownload.aspx Hope you like it! Please do let me know your feedback by providing comments to my blog post. Kind Regards, Hajan

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  • Automatic Properties, Collection Initializers, and Implicit Line Continuation support with VB 2010

    - by ScottGu
    [In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu] This is the eighteenth in a series of blog posts I’m doing on the upcoming VS 2010 and .NET 4 release. A few days ago I blogged about two new language features coming with C# 4.0: optional parameters and named arguments.  Today I’m going to post about a few of my favorite new features being added to VB with VS 2010: Auto-Implemented Properties, Collection Initializers, and Implicit Line Continuation support. Auto-Implemented Properties Prior to VB 2010, implementing properties within a class using VB required you to explicitly declare the property as well as implement a backing field variable to store its value.  For example, the code below demonstrates how to implement a “Person” class using VB 2008 that exposes two public properties - “Name” and “Age”:   While explicitly declaring properties like above provides maximum flexibility, I’ve always found writing this type of boiler-plate get/set code tedious when you are simply storing/retrieving the value from a field.  You can use VS code snippets to help automate the generation of it – but it still generates a lot of code that feels redundant.  C# 2008 introduced a cool new feature called automatic properties that helps cut down the code quite a bit for the common case where properties are simply backed by a field.  VB 2010 also now supports this same feature.  Using the auto-implemented properties feature of VB 2010 we can now implement our Person class using just the code below: When you declare an auto-implemented property, the VB compiler automatically creates a private field to store the property value as well as generates the associated Get/Set methods for you.  As you can see above – the code is much more concise and easier to read. The syntax supports optionally initializing the properties with default values as well if you want to: You can learn more about VB 2010’s automatic property support from this MSDN page. Collection Initializers VB 2010 also now supports using collection initializers to easily create a collection and populate it with an initial set of values.  You identify a collection initializer by declaring a collection variable and then use the From keyword followed by braces { } that contain the list of initial values to add to the collection.  Below is a code example where I am using the new collection initializer feature to populate a “Friends” list of Person objects with two people, and then bind it to a GridView control to display on a page: You can learn more about VB 2010’s collection initializer support from this MSDN page. Implicit Line Continuation Support Traditionally, when a statement in VB has been split up across multiple lines, you had to use a line-continuation underscore character (_) to indicate that the statement wasn’t complete.  For example, with VB 2008 the below LINQ query needs to append a “_” at the end of each line to indicate that the query is not complete yet: The VB 2010 compiler and code editor now adds support for what is called “implicit line continuation support” – which means that it is smarter about auto-detecting line continuation scenarios, and as a result no longer needs you to explicitly indicate that the statement continues in many, many scenarios.  This means that with VB 2010 we can now write the above code with no “_” at all: The implicit line continuation feature also works well when editing XML Literals within VB (which is pretty cool). You can learn more about VB 2010’s Implicit Line Continuation support and many of the scenarios it supports from this MSDN page (scroll down to the “Implicit Line Continuation” section to find details). Summary The above three VB language features are but a few of the new language and code editor features coming with VB 2010.  Visit this site to learn more about some of the other VB language features coming with the release.  Also subscribe to the VB team’s blog to learn more and stay up-to-date with the posts they the team regularly publishes. Hope this helps, Scott

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  • Subterranean IL: Pseudo custom attributes

    - by Simon Cooper
    Custom attributes were designed to make the .NET framework extensible; if a .NET language needs to store additional metadata on an item that isn't expressible in IL, then an attribute could be applied to the IL item to represent this metadata. For instance, the C# compiler uses DecimalConstantAttribute and DateTimeConstantAttribute to represent compile-time decimal or datetime constants, which aren't allowed in pure IL, and FixedBufferAttribute to represent fixed struct fields. How attributes are compiled Within a .NET assembly are a series of tables containing all the metadata for items within the assembly; for instance, the TypeDef table stores metadata on all the types in the assembly, and MethodDef does the same for all the methods and constructors. Custom attribute information is stored in the CustomAttribute table, which has references to the IL item the attribute is applied to, the constructor used (which implies the type of attribute applied), and a binary blob representing the arguments and name/value pairs used in the attribute application. For example, the following C# class: [Obsolete("Please use MyClass2", true)] public class MyClass { // ... } corresponds to the following IL class definition: .class public MyClass { .custom instance void [mscorlib]System.ObsoleteAttribute::.ctor(string, bool) = { string('Please use MyClass2' bool(true) } // ... } and results in the following entry in the CustomAttribute table: TypeDef(MyClass) MemberRef(ObsoleteAttribute::.ctor(string, bool)) blob -> {string('Please use MyClass2' bool(true)} However, there are some attributes that don't compile in this way. Pseudo custom attributes Just like there are some concepts in a language that can't be represented in IL, there are some concepts in IL that can't be represented in a language. This is where pseudo custom attributes come into play. The most obvious of these is SerializableAttribute. Although it looks like an attribute, it doesn't compile to a CustomAttribute table entry; it instead sets the serializable bit directly within the TypeDef entry for the type. This flag is fully expressible within IL; this C#: [Serializable] public class MySerializableClass {} compiles to this IL: .class public serializable MySerializableClass {} For those interested, a full list of pseudo custom attributes is available here. For the rest of this post, I'll be concentrating on the ones that deal with P/Invoke. P/Invoke attributes P/Invoke is built right into the CLR at quite a deep level; there are 2 metadata tables within an assembly dedicated solely to p/invoke interop, and many more that affect it. Furthermore, all the attributes used to specify p/invoke methods in C# or VB have their own keywords and syntax within IL. For example, the following C# method declaration: [DllImport("mscorsn.dll", SetLastError = true)] [return: MarshalAs(UnmanagedType.U1)] private static extern bool StrongNameSignatureVerificationEx( [MarshalAs(UnmanagedType.LPWStr)] string wszFilePath, [MarshalAs(UnmanagedType.U1)] bool fForceVerification, [MarshalAs(UnmanagedType.U1)] ref bool pfWasVerified); compiles to the following IL definition: .method private static pinvokeimpl("mscorsn.dll" lasterr winapi) bool marshal(unsigned int8) StrongNameSignatureVerificationEx( string marshal(lpwstr) wszFilePath, bool marshal(unsigned int8) fForceVerification, bool& marshal(unsigned int8) pfWasVerified) cil managed preservesig {} As you can see, all the p/invoke and marshal properties are specified directly in IL, rather than using attributes. And, rather than creating entries in CustomAttribute, a whole bunch of metadata is emitted to represent this information. This single method declaration results in the following metadata being output to the assembly: A MethodDef entry containing basic information on the method Four ParamDef entries for the 3 method parameters and return type An entry in ModuleRef to mscorsn.dll An entry in ImplMap linking ModuleRef and MethodDef, along with the name of the function to import and the pinvoke options (lasterr winapi) Four FieldMarshal entries containing the marshal information for each parameter. Phew! Applying attributes Most of the time, when you apply an attribute to an element, an entry in the CustomAttribute table will be created to represent that application. However, some attributes represent concepts in IL that aren't expressible in the language you're coding in, and can instead result in a single bit change (SerializableAttribute and NonSerializedAttribute), or many extra metadata table entries (the p/invoke attributes) being emitted to the output assembly.

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  • F# in ASP.NET, mathematics and testing

    - by DigiMortal
    Starting from Visual Studio 2010 F# is full member of .NET Framework languages family. It is functional language with syntax specific to functional languages but I think it is time for us also notice and study functional languages. In this posting I will show you some examples about cool things other people have done using F#. F# and ASP.NET As I am ASP/ASP.NET MVP I am – of course – interested in how people use different languages and technologies with ASP.NET. C# MVP Tomáš Petrícek writes about developing ASP.NET MVC applications using F#. He also shows how to use LINQ To SQL in F# (using F# PowerPack) and provides sample solution and Visual Studio 2010 template for F# MVC web applications. You may also find interesting how you can create controllers in F#. Excellent work, Tomáš! Vladimir Matveev has interesting example about how to use F# and ApplicationHost class to process ASP.NET requests ouside of IIS. This is simple and very straight-forward example and I strongly suggest you to take a look at it. Very cool example is project Strom in Codeplex. Storm is web services testing tool that is fully written on F#. Take a look at this site because Codeplex offers also source code besides binaries. Math Functional languages are strong in fields like mathematics and physics. When I wrote my C# example about BigInteger class I found out that recursive version of Fibonacci algorithm in C# is not performing well. In same time I made same experiment on F# and in F# there were no performance problems with recursive version. You can find F# version of Fibonacci algorithm from Bob Palmer’s blog posting Fibonacci numbers in F#. Although golden spiral is useful for solving many problems I looked for some practical code example and found one. Kean Walmsley published in his Through the Interface blog very interesting posting Creating Fibonacci spirals in AutoCAD using F#. There are also other cool examples you may be interested in. Using numerical components by Extreme Optimization  it is possible to make some numerical integration (quadrature method) using F# (also C# example is available). fsharp.it introduces factorials calculation on F#. Robert Pickering has made very good work on programming The Game of Life in Silverlight and F# – I definitely suggest you to try out this example as it is very illustrative too. Who wants something more complex may take a look at Newton basin fractal example in F# by Jonathan Birge. Testing After some searching and surfing I found out that there is almost everything available for F# to write tests and test your F# code. FsCheck - FsCheck is a port of Haskell's QuickCheck. Important parts of the manual for using FsCheck is almost literally "adapted" from the QuickCheck manual and paper. Any errors and omissions are entirely my responsibility. FsTest - This project is designed to Language Oriented Programming constructs around unit testing and behavior testing in F#. The goal of this project is to create a Domain Specific Language for testing F# code in a way that makes sense for functional programming. FsUnit - FsUnit makes unit-testing with F# more enjoyable. It adds a special syntax to your favorite .NET testing framework. xUnit.NET - xUnit.net is a developer testing framework, built to support Test Driven Development, with a design goal of extreme simplicity and alignment with framework features. It is compatible with .NET Framework 2.0 and later, and offers several runners: console, GUI, MSBuild, and Visual Studio integration via TestDriven.net, CodeRush Test Runner and Resharper. It also offers test project integration for ASP.NET MVC. Getting started Well, as a first thing you need Visual Studio 2010. Then take a look at these resources: F# samples @ MSDN Microsoft F# Developer Center @ MSDN F# Language Reference @ MSDN F# blog F# forums Real World Functional Programming: With Examples in F# and C# (Amazon) Happy F#-ing! :)

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  • Windows Azure Use Case: New Development

    - by BuckWoody
    This is one in a series of posts on when and where to use a distributed architecture design in your organization's computing needs. You can find the main post here: http://blogs.msdn.com/b/buckwoody/archive/2011/01/18/windows-azure-and-sql-azure-use-cases.aspx Description: Computing platforms evolve over time. Originally computers were directed by hardware wiring - that, the “code” was the path of the wiring that directed an electrical signal from one component to another, or in some cases a physical switch controlled the path. From there software was developed, first in a very low machine language, then when compilers were created, computer languages could more closely mimic written statements. These language statements can be compiled into the lower-level machine language still used by computers today. Microprocessors replaced logic circuits, sometimes with fewer instructions (Reduced Instruction Set Computing, RISC) and sometimes with more instructions (Complex Instruction Set Computing, CISC). The reason this history is important is that along each technology advancement, computer code has adapted. Writing software for a RISC architecture is significantly different than developing for a CISC architecture. And moving to a Distributed Architecture like Windows Azure also has specific implementation details that our code must follow. But why make a change? As I’ve described, we need to make the change to our code to follow advances in technology. There’s no point in change for its own sake, but as a new paradigm offers benefits to our users, it’s important for us to leverage those benefits where it makes sense. That’s most often done in new development projects. It’s a far simpler task to take a new project and adapt it to Windows Azure than to try and retrofit older code designed in a previous computing environment. We can still use the same coding languages (.NET, Java, C++) to write code for Windows Azure, but we need to think about the architecture of that code on a new project so that it runs in the most efficient, cost-effective way in a Distributed Architecture. As we receive new requests from the organization for new projects, a distributed architecture paradigm belongs in the decision matrix for the platform target. Implementation: When you are designing new applications for Windows Azure (or any distributed architecture) there are many important details to consider. But at the risk of over-simplification, there are three main concepts to learn and architect within the new code: Stateless Programming - Stateless program is a prime concept within distributed architectures. Rather than each server owning the complete processing cycle, the information from an operation that needs to be retained (the “state”) should be persisted to another location c(like storage) common to all machines involved in the process.  An interesting learning process for Stateless Programming (although not unique to this language type) is to learn Functional Programming. Server-Side Processing - Along with developing using a Stateless Design, the closer you can locate the code processing to the data, the less expensive and faster the code will run. When you control the network layer, this is less important, since you can send vast amounts of data between the server and client, allowing the client to perform processing. In a distributed architecture, you don’t always own the network, so it’s performance is unpredictable. Also, you may not be able to control the platform the user is on (such as a smartphone, PC or tablet), so it’s imperative to deliver only results and graphical elements where possible.  Token-Based Authentication - Also called “Claims-Based Authorization”, this code practice means instead of allowing a user to log on once and then running code in that context, a more granular level of security is used. A “token” or “claim”, often represented as a Certificate, is sent along for a series or even one request. In other words, every call to the code is authenticated against the token, rather than allowing a user free reign within the code call. While this is more work initially, it can bring a greater level of security, and it is far more resilient to disconnections. Resources: See the references of “Nondistributed Deployment” and “Distributed Deployment” at the top of this article for more information with graphics:  http://msdn.microsoft.com/en-us/library/ee658120.aspx  Stack Overflow has a good thread on functional programming: http://stackoverflow.com/questions/844536/advantages-of-stateless-programming  Another good discussion on Stack Overflow on server-side processing is here: http://stackoverflow.com/questions/3064018/client-side-or-server-side-processing Claims Based Authorization is described here: http://msdn.microsoft.com/en-us/magazine/ee335707.aspx

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  • Windows Azure Use Case: New Development

    - by BuckWoody
    This is one in a series of posts on when and where to use a distributed architecture design in your organization's computing needs. You can find the main post here: http://blogs.msdn.com/b/buckwoody/archive/2011/01/18/windows-azure-and-sql-azure-use-cases.aspx Description: Computing platforms evolve over time. Originally computers were directed by hardware wiring - that, the “code” was the path of the wiring that directed an electrical signal from one component to another, or in some cases a physical switch controlled the path. From there software was developed, first in a very low machine language, then when compilers were created, computer languages could more closely mimic written statements. These language statements can be compiled into the lower-level machine language still used by computers today. Microprocessors replaced logic circuits, sometimes with fewer instructions (Reduced Instruction Set Computing, RISC) and sometimes with more instructions (Complex Instruction Set Computing, CISC). The reason this history is important is that along each technology advancement, computer code has adapted. Writing software for a RISC architecture is significantly different than developing for a CISC architecture. And moving to a Distributed Architecture like Windows Azure also has specific implementation details that our code must follow. But why make a change? As I’ve described, we need to make the change to our code to follow advances in technology. There’s no point in change for its own sake, but as a new paradigm offers benefits to our users, it’s important for us to leverage those benefits where it makes sense. That’s most often done in new development projects. It’s a far simpler task to take a new project and adapt it to Windows Azure than to try and retrofit older code designed in a previous computing environment. We can still use the same coding languages (.NET, Java, C++) to write code for Windows Azure, but we need to think about the architecture of that code on a new project so that it runs in the most efficient, cost-effective way in a Distributed Architecture. As we receive new requests from the organization for new projects, a distributed architecture paradigm belongs in the decision matrix for the platform target. Implementation: When you are designing new applications for Windows Azure (or any distributed architecture) there are many important details to consider. But at the risk of over-simplification, there are three main concepts to learn and architect within the new code: Stateless Programming - Stateless program is a prime concept within distributed architectures. Rather than each server owning the complete processing cycle, the information from an operation that needs to be retained (the “state”) should be persisted to another location c(like storage) common to all machines involved in the process.  An interesting learning process for Stateless Programming (although not unique to this language type) is to learn Functional Programming. Server-Side Processing - Along with developing using a Stateless Design, the closer you can locate the code processing to the data, the less expensive and faster the code will run. When you control the network layer, this is less important, since you can send vast amounts of data between the server and client, allowing the client to perform processing. In a distributed architecture, you don’t always own the network, so it’s performance is unpredictable. Also, you may not be able to control the platform the user is on (such as a smartphone, PC or tablet), so it’s imperative to deliver only results and graphical elements where possible.  Token-Based Authentication - Also called “Claims-Based Authorization”, this code practice means instead of allowing a user to log on once and then running code in that context, a more granular level of security is used. A “token” or “claim”, often represented as a Certificate, is sent along for a series or even one request. In other words, every call to the code is authenticated against the token, rather than allowing a user free reign within the code call. While this is more work initially, it can bring a greater level of security, and it is far more resilient to disconnections. Resources: See the references of “Nondistributed Deployment” and “Distributed Deployment” at the top of this article for more information with graphics:  http://msdn.microsoft.com/en-us/library/ee658120.aspx  Stack Overflow has a good thread on functional programming: http://stackoverflow.com/questions/844536/advantages-of-stateless-programming  Another good discussion on Stack Overflow on server-side processing is here: http://stackoverflow.com/questions/3064018/client-side-or-server-side-processing Claims Based Authorization is described here: http://msdn.microsoft.com/en-us/magazine/ee335707.aspx

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  • PHP and Ruby: how to leverage both? and, is it worth it?

    - by dukeofgaming
    As you might have noticed from the title, this is not a "PHP or Ruby", or a "PHP vs. Ruby" question. This is a question on how to leverage PHP + Ruby in the same business. I myself am a PHP developer, I love the language because of its convenience and I specially love the ecosystem of resources that surround it: Joomla, Drupal, Wordpress, Symfony2, Doctrine2, etc. However, the language itself can be a little disappointing sometimes. OTOH, Ruby looks like a very beautiful language and —from studying it superficially in several aspects— I could say it is leaner than Python as a language per se. However, from what I've seen there is pretty much only RoR making noise, and I don't like RoR so much (mainly because its model layer). As Co-CEO and CTO at my company I'm trying to think outside of the box since I want to start to focus on the human side of technology and see if its sane to use both PHP and Ruby. Here are some random thoughts: Ruby folk seem to be generally better suited programmers than PHP folk (in terms of averages), I know the previous statement is somewhat baloney because very good and well architected PHP can be written, but I'd say the Ruby programmer culture is better than PHP's. The thing about Ruby is that it seems better suited for rapid development, I don't really know if this is only the case for RoR, but I do know that there are certain practices (perhaps not so good) like monkey patching that let business needs be satified quicker. From a marketing point of view (yep, sometimes you need to leverage the marketing BS for the sake of your company) Ruby seems better while PHP carries some stigmas. PHP 5.4 is bringing traits, and that is better/cleaner than mixins. That could really make PHP as lean as Ruby —or more— for certain stuff. Now, concretely, my questions: Would a PHP programmer want to learn Ruby?, I know I do, but conversely, would a Ruby programmer want to learn PHP?. What kinds of projects or situations would be better suited for Ruby that are not suited for PHP?. What is the actual ecosystem of Ruby?, aside from RoR, I have not seen other hyped technologies/frameworks (I've seen RSpec, but I confess being a total noob on what BDD really consists of and its implications). Supposing there are a certain type of projects ideal for Ruby, would there be a moment that its better to move it to PHP?. I know PHP can handle lots of stuff, but I've read that Ruby has its limitations when scaling (or is that RoR?, or is that baloney for both?). Finally and most importantly, would it be sane to maintain projects in two languages?, or is that just stupid. As I said, it looks like Ruby is leaner on the short term and that can make a project happen and succeed, but I'm not so sure about that on the long run. I'm looking for insights mainly from people that know well the strengths and weaknesses of the languages —preferably both of them— and Ruby's ecosystem in real practice, meaning: frameworks and applications like the ones I quoted from PHP's ecosystem. Best regards and thanks for your time.

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  • installArchives() failed: perl: warning: Setting locale failed.

    - by Alwin Doss
    I get the following error while updating ubuntu 12.04 LTS installArchives() failed: perl: warning: Setting locale failed. perl: warning: Please check that your locale settings: LANGUAGE = (unset), LC_ALL = (unset), LANG = "en_IN.ISO8859-1" are supported and installed on your system. perl: warning: Falling back to the standard locale ("C"). locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory Preconfiguring packages ... perl: warning: Setting locale failed. perl: warning: Please check that your locale settings: LANGUAGE = (unset), LC_ALL = (unset), LANG = "en_IN.ISO8859-1" are supported and installed on your system. perl: warning: Falling back to the standard locale ("C"). locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory Preconfiguring packages ... perl: warning: Setting locale failed. perl: warning: Please check that your locale settings: LANGUAGE = (unset), LC_ALL = (unset), LANG = "en_IN.ISO8859-1" are supported and installed on your system. perl: warning: Falling back to the standard locale ("C"). locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory Preconfiguring packages ... perl: warning: Setting locale failed. perl: warning: Please check that your locale settings: LANGUAGE = (unset), LC_ALL = (unset), LANG = "en_IN.ISO8859-1" are supported and installed on your system. perl: warning: Falling back to the standard locale ("C"). locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory Preconfiguring packages ... (Reading database ... (Reading database ... 5%% (Reading database ... 10%% (Reading database ... 15%% (Reading database ... 20%% (Reading database ... 25%% (Reading database ... 30%% (Reading database ... 35%% (Reading database ... 40%% (Reading database ... 45%% (Reading database ... 50%% (Reading database ... 55%% (Reading database ... 60%% (Reading database ... 65%% (Reading database ... 70%% (Reading database ... 75%% (Reading database ... 80%% (Reading database ... 85%% (Reading database ... 90%% (Reading database ... 95%% (Reading database ... 100%% (Reading database ... 430284 files and directories currently installed.) Preparing to replace libxml2-dev 2.7.8.dfsg-5.1ubuntu4.1 (using .../libxml2-dev_2.7.8.dfsg-5.1ubuntu4.2_i386.deb) ... Unpacking replacement libxml2-dev ... Preparing to replace libxml2 2.7.8.dfsg-5.1ubuntu4.1 (using .../libxml2_2.7.8.dfsg-5.1ubuntu4.2_i386.deb) ... Unpacking replacement libxml2 ... Preparing to replace gstreamer0.10-plugins-bad 0.10.22.3-2ubuntu2 (using .../gstreamer0.10-plugins-bad_0.10.22.3-2ubuntu2.1_i386.deb) ... Unpacking replacement gstreamer0.10-plugins-bad ... Preparing to replace libgstreamer-plugins-bad0.10-0 0.10.22.3-2ubuntu2 (using .../libgstreamer-plugins-bad0.10-0_0.10.22.3-2ubuntu2.1_i386.deb) ... Unpacking replacement libgstreamer-plugins-bad0.10-0 ... Preparing to replace ubuntu-keyring 2011.11.21 (using .../ubuntu-keyring_2011.11.21.1_all.deb) ... /var/lib/dpkg/info/samba4.postinst: 14: /var/lib/dpkg/info/samba4.postinst: /usr/share/samba/setoption.pl: Permission denied dpkg: error processing samba4 (--configure): subprocess installed post-installation script returned error exit status 126

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  • Surviving MATLAB and R as a Hardcore Programmer

    - by dsimcha
    I love programming in languages that seem geared towards hardcore programmers. (My favorites are Python and D.) MATLAB is geared towards engineers and R is geared towards statisticians, and it seems like these languages were designed by people who aren't hardcore programmers and don't think like hardcore programmers. I always find them somewhat awkward to use, and to some extent I can't put my finger on why. Here are some issues I have managed to identify: (Both): The extreme emphasis on vectors and matrices to the extent that there are no true primitives. (Both): The difficulty of basic string manipulation. (Both): Lack of or awkwardness in support for basic data structures like hash tables and "real", i.e. type-parametric and nestable, arrays. (Both): They're really, really slow even by interpreted language standards, unless you bend over backwards to vectorize your code. (Both): They seem to not be designed to interact with the outside world. For example, both are fairly bulky programs that take a while to launch and seem to not be designed to make simple text filter programs easy to write. Furthermore, the lack of good string processing makes file I/O in anything but very standard forms near impossible. (Both): Object orientation seems to have a very bolted-on feel. Yes, you can do it, but it doesn't feel much more idiomatic than OO in C. (Both): No obvious, simple way to get a reference type. No pointers or class references. For example, I have no idea how you roll your own linked list in either of these languages. (MATLAB): You can't put multiple top level functions in a single file, encouraging very long functions and cut-and-paste coding. (MATLAB): Integers apparently don't exist as a first class type. (R): The basic builtin data structures seem way too high level and poorly documented, and never seem to do quite what I expect given my experience with similar but lower level data structures. (R): The documentation is spread all over the place and virtually impossible to browse or search. Even D, which is often knocked for bad documentation and is still fairly alpha-ish, is substantially better as far as I can tell. (R): At least as far as I'm aware, there's no good IDE for it. Again, even D, a fairly alpha-ish language with a small community, does better. In general, I also feel like MATLAB and R could be easily replaced by plain old libraries in more general-purpose langauges, if sufficiently comprehensive libraries existed. This is especially true in newer general purpose languages that include lots of features for library writers. Why do R and MATLAB seem so weird to me? Are there any other major issues that you've noticed that may make these languages come off as strange to hardcore programmers? When their use is necessary, what are some good survival tips? Edit: I'm seeing one issue from some of the answers I've gotten. I have a strong personal preference, when I analyze data, to have one script that incorporates the whole pipeline. This implies that a general purpose language needs to be used. I hate having to write a script to "clean up" the data and spit it out, then another to read it back in a completely different environment, etc. I find the friction of using MATLAB/R for some of my work and a completely different language with a completely different address space and way of thinking for the rest to be a huge source of friction. Furthermore, I know there are glue layers that exist, but they always seem to be horribly complicated and a source of friction.

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