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• Using ASP.NET Membership Provider with an ACL

  - by geekrutherford

  Up until recently one of my applications has used the membership provider within ASP.NET exclusively. However, it has been proposed that while the currently defined roles are beneficial, security needs to be more granular to restrict both access to certain pages and functionality present within a given page.   Unfortunately, the role based security ASP.NET gives you out of the box falls down in this area. This is not due to a lack of foresight by Microsoft, but rather it was simply not designed for implementing both role based security and any inherent ACL you may define within these roles. Mind you some would say an ACL is independent of the role to which a user belongs and is assigned to the user directly.   The application mentioned here has it's own User object (which encapsulates the membership provider user object as a property) and SQL Server table to store extended information not present in the aspnet_users table. While I could have modified the aspnet membership schema to suit the applications needs, it seemed smarter to simply create a separate table with a foreign key back to the aspnet_users table.   Since I have a separate object to store extended user information, I simply created an ACL object and expose it as a property of my user object.   This is all well and good, but it does not help in regards to the SiteMapProvider and restricting access at the page level based on the users ACL.   The straightforward answer would be to develop some code within the databound event for the menu that checks the page title and has hardcoded logic that dictates a user must have certain permissions turned on. The problem with this approach is that it's HARDCODED!!! If you need to change access to a page you'd need to do a build and go through your normal deployment process....ugh!!!   An alternative method, albeit not perfect, is to utilize the resourceKey property on the SiteMapNodes in the SiteMap file with the name of the required permission to view the page. Within the databound event for your menu you iterate the SiteMapNodes in the menus SiteMapProvider looking for a match at the page level based on title. When a match is detected, you have a switch/case on the SiteMapNodes resourceKey (the name of the ACL permission required). The case for the resourceKey ensures the users ACL permission is turned on and viola!!!   This is noteably not perfect in that it is using the resourceKey in a manner other than intended.  Since the application is not localized, using it in the manner described it not an issue.   Below is a sample SiteMap file with the resourceKey used as the ACL permission identifier:     Below is the ItemDataBound event. This application uses the Telerik Menu control:

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• Rails - How to use modal form to add object in one model, then reflect that change on main page?

  - by Jim

  I'm working on a Rails app and I've come across a situation where I'm unsure of the cleanest way to proceed. I posted a question on SO with code samples and such - it has received no answers, and the more I think about the problem, the more I think I might be approaching this the wrong way. (See the SO question at http://stackoverflow.com/questions/9521319/how-to-reference-form-when-rendering-partial-from-js-erb-file) So, in more of a generic architecture type question: Right now I have a form where a user can add a new recipe. The form also allows the user to select ingredients (it uses a collection_select which contains Ingredient.all). The catch is - I'd like the user to be able to add a new ingredient on the fly, without leaving the recipe form. Using a hidden div and some jQuery/AJAX, I have a link the user can click to popup a modal form containing ingredients/new.html.erb which is a simple form. When that form is submitted, I call ingredients/create.js.erb to validate the ingredient was saved and hide the modal div. Now I am back to my recipe form, but my collection_select hasn't updated. It seems I have a few choices here: try and re-render the collection_select portion of the form so it grabs a new list of ingredients. This was the method I was attempting when I wrote the SO question. The problem I run into is the partial I use for the collection_select needs the parent form passed in, and when I try and render from the JS file I don't know how to pass it the form object. Reload the recipe form. This works (the collection_select now contains the new ingredient), but the user loses any progress they made on the recipe form. I would need a way to persist the form data - I thought about manually passing the values back and forth, but that is sloppy and there has to be a better way... Try and manually insert the tags using jQuery - this would be simple, but because I'm allowing for multiple ingredients to be added, I can't be certain what ID to target. Now, I can't be the only person to have this issue - so is there an easier way I'm missing? I like option 2 above, but I don't know if there's an easy way to grab the entire params hash as if I had submitted the main recipes form. Hopefully someone can point me in the right direction so I can find an answer to this... If this doesn't make any sense at all, let me know - I can post code samples if you want, but most of the pertinent code is up on the SO question. Thanks!

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• What can I do to make sure my code gets maintained in a developer light environment?

  - by asjohnson

  I am a contract data analyst, so I bounce between jobs every 3-6 months, which I find to be a good fit for me, but it leads to some problems when it comes to coding. I mostly do statistics (I've asked a similar question on cross validated, but the answers there are not relevant here), but I have also found out that the business world loves excel and loves copying and pasting the same thing over and over again even more. This led me to learn how to write VBA scripts and then VB.NET programs to automate as many of these reports as I can. I am certain my programs are not the most elegant, but I put a good bit of effort into making sure they work under as many cases as I can test, I add in exceptions and try to code so the program can handle changes in the files that it processes, but there is a limit, if you remove a huge portion of the data, there is a good chance my program is going to trip up, which I accept will inevitably happen. Usually a pretty minor change in the code fixes the problem and I do try and comment my code and make it readable under the assumption that some other person will have to read it some day. My problem is that I generally get put on teams of folks with essentially no experience with programming (like VBA would be a huge stretch for anyone I work directly with). I am wondering what I should be doing as the person that wrote the code to do my best to keep it maintained. I have two approaches in mind (outlined next), but would be very happy to get any advice. Solution 1: Find the more tech savvy coworkers and run them through the programs and what basic changes can be made. Honestly automating excel is about as easy as it can get when it comes to programming, so I feel like I could teach someone the basics of maintaining it pretty quick. Solution 2: Get in touch with the IT department and show them what is going on and maybe they will be able to help. The problem here is that the IT department is constantly swamped (as I'm sure many of you know) and I feel like kind of a jerk for dumping more things on them. I do leave my personal email address with places and am willing to answer quick questions via email, but I view the need for more exhaustive maintenance as something of an inevitability and would like to make sure I do my due diligence to make sure it gets done. I imagine some combination of the two approaches outlined there, but is there any kind of heads up I should give IT? I feel like I would be annoyed if I started getting requests to fix a program that I had never seen from some random guy that is no longer there.

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• Geek Bike Ride JavaOne 2012

  - by Tori Wieldt

  "Geek Bike Ride?" the clerk at the bike rental shop asked. "Are you guys all from the same company?" "We aren't even from the same country!" we answered. "I'm from Russia." "We're from Germany."  "I'm from Belgium." "I'm from Palo Alto." "I'm from Japan."  "We're from Brazil." "We're from Brazil." "I'm from Sweden." "Coooool" was all she could say. She was right. The Geek Bike Ride was cooool. We had 39 bike riders and one skater show up Saturday for a great route from San Francisco's Fisherman's Wharf, across the Golden Gate bridge, to Saulsalito, and back to the city by ferry. Duke Bike jerseys, sponsored by OTN, were given out. To make sure Java developers got them, each person had to answer a Java question to get a jersey. The questions were really hard, like "Who is the Father of Java?" "What's the biggest Java conference in San Francisco?" The best was when the question was "Name one of Duke's Choice Award winner from this year," and Régina ten Bruggencate answered answered "Me!"  It was foggy throughout the day, with the sun poking out occasionally. The fog was thickest on the bridge, more that one rider commented that we were "in the cloud." It was a great day to meet new friends, and have a chat with old friends. We all had fun, though some of us may more a little more slowly during JavaOne. Ride on!  Photos by permission by Arun Gupta and Yoshio Terada. Thanks, guys!

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• Upstart: How does rc job work / order of (contradicting) "start on ..." and "stop on ..." stanzas

  - by Binarus

  Hi, I just can't understand how Upstart's rc job definition in Natty 11.04 works. To illustrate the problem, here is the definition (empty lines and comments are left out): start on runlevel [0123456] stop on runlevel [!$RUNLEVEL] export RUNLEVEL export PREVLEVEL console output env INIT_VERBOSE task exec /etc/init.d/rc $RUNLEVEL Let's suppose we currently are in runlevel 2 and the rc job is stopped (that is exactly the situation after booting my box and logging in via SSH). Now, let's assume that the system switches to runlevel 3, for example due to a command like "telinit 3" given by root. What will happen to the rc job? Obviously, the rc job will be started since it is currently stopped and the event runlevel 3 is matching the start events. But from now on, things are unclear to me: According to the manual $RUNLEVEL evaluates to the new runlevel when the job is started (that means 3 in our example). Therefore, the next stanza "stop on runlevel [!$RUNLEVEL]" translates to "stop on runlevel [!3]"; that means we have a first stanza which will trigger the job, but the second stanza will never stop the job and seems to be useless. Since I know that the Ubuntu / Upstart people won't do useless things, I must be heavily misunderstanding something. I would be grateful for any explanation. While trying to understand this, an additional question came to my mind. If I had contradicting start and stop triggers, for example start on foo stop on foo what would happen? I swear I never will do that, but I am nevertheless very interested in how Upstart handles that on the theoretical level. Thank you very much! Editing the question as a reaction on geekosaur's first answer: I can see the parallelism, but it is not that easy (at least, not to me). Let's assume the job aurrently is still running, and a new runlevel event comes in (of course, the new runlevel is different from the current one). Then, the following should happen: 1) The job is single instance. That means that "start on ..." won't be triggered since the job is currently running; $RUNLEVEL is not touched. 2) "stop on ..." will be triggered since the new runlevel is different from $RUNLEVEL, so the job will be aborted. 3) Now, the job is stopped and waiting. I can't see how it is restarted with the new runlevel. AFAIK, initctl emits events only once, so "start on ..." won't be triggered and the new runlevel won't be entered. I know that I still misunderstanding something, and I am grateful for explanations. Thank you very much!

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• Simplifying C++11 optimal parameter passing when a copy is needed

  - by Mr.C64

  It seems to me that in C++11 lots of attention was made to simplify returning values from functions and methods, i.e.: with move semantics it's possible to simply return heavy-to-copy but cheap-to-move values (while in C++98/03 the general guideline was to use output parameters via non-const references or pointers), e.g.: // C++11 style vector<string> MakeAVeryBigStringList(); // C++98/03 style void MakeAVeryBigStringList(vector<string>& result); On the other side, it seems to me that more work should be done on input parameter passing, in particular when a copy of an input parameter is needed, e.g. in constructors and setters. My understanding is that the best technique in this case is to use templates and std::forward<>, e.g. (following the pattern of this answer on C++11 optimal parameter passing): class Person { std::string m_name; public: template <class T, class = typename std::enable_if < std::is_constructible<std::string, T>::value >::type> explicit Person(T&& name) : m_name(std::forward<T>(name)) { } ... }; A similar code could be written for setters. Frankly, this code seems boilerplate and complex, and doesn't scale up well when there are more parameters (e.g. if a surname attribute is added to the above class). Would it be possible to add a new feature to C++11 to simplify code like this (just like lambdas simplify C++98/03 code with functors in several cases)? I was thinking of a syntax with some special character, like @ (since introducing a &&& in addition to && would be too much typing :) e.g.: class Person { std::string m_name; public: /* Simplified syntax to produce boilerplate code like this: template <class T, class = typename std::enable_if < std::is_constructible<std::string, T>::value >::type> */ explicit Person(std::string@ name) : m_name(name) // implicit std::forward as well { } ... }; This would be very convenient also for more complex cases involving more parameters, e.g. Person(std::string@ name, std::string@ surname) : m_name(name), m_surname(surname) { } Would it be possible to add a simplified convenient syntax like this in C++? What would be the downsides of such a syntax?

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• Booting Ubuntu on HP Pavilion g7 - 13.04 [duplicate]

  - by death2040

  This question already has an answer here: My computer boots to a black screen, what options do I have to fix it? 24 answers I have a HP Pavilion G7 with an AMD A4 processor and Radeon graphics. I want to install Ubuntu on my laptop but whenever I put the Ubuntu live CD in it and boot to it, the screen shows the Ubuntu logo and the four little dots then after about a minute or two the screen goes black. I can tell the screen is still on but it doesn't have anything on it. I'm beginning to wonder if its a driver problem but I can't really install the drivers when I cant even get Ubuntu to show anything except a loading screen. I've already tried using 12.04 and 12.10 and all the others down to Ubuntu 10. none of them worked. All the other versions don't even show the Ubuntu logo. I'd prefer to have Ubuntu 13.04 on it if its possible but I haven't had any luck finding a solution. I've also tried using WUBI installer in Windows 7 but all that did was make my computer slower for windows and it does the same with the screen when i boot it to Ubuntu. I'm trying to use Ubuntu alongside Windows 7. I cant find any solution on Google. It wont load anything and I know that there is a program called grub on Ubuntu that I used on my desktop computer when it had graphics trouble but the trouble with my desktop was minor things like the screen would flash and then show weird patterns on the screen. But I can't find anything on what to do with the HP laptop. Please help. I use this laptop a lot for games on Windows 7 and I just want to use Ubuntu for when I take my laptop to school and for school stuff. Edit: I just tried booting it in nomodeset and some other things and still didn't work. It did boot up but now when it goes to install alongside windows it crashes and says Ubuntu is forcing reboot or something like that Also, this question is different from the black screen at boot issue because when I do use nomodeset on my computer and select install Ubuntu it will go as far as the screen where you can choose to replace Windows or run alongside Windows. Then after I click continue it ejects the live CD and turns off my computer without installing anything. The error message it shows when it ejects the disk says signal 15, shutting down - modem manager [1675]: <info> Caught nm-dispatcher.action: Caught signal 15, shutting down... *Deconfiguring network interfaces... Please remove installation media and close the tray (if any) then press ENTER *Deactivating swap... *Stopping remaining crypto disks... *stopping early crypto disks... unmount: /run/lock: not mounted unmount: /run/shm: not mounted

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• How to keep balance / Unlock items / achievement rules

  - by Mark Knol

  I'm working on an engine for a game, too learn javascript and just because its fun. I'm a flashdeveloper, I know how to build websites. Now making games is a different challenge, javascript is a challenge, but I'd love to learn how to structure code and what patterns are common. I dont mind if the game ever finish, I'm mostly interested in the programming part of it. I dont have a particular endresult in mind, so I'll see where it takes me. I currently have a system where you can buy items. The items cost a specified amount of gold, silver, diamonds etc. When you have selected and bought the item, it takes time before getting rewarded. When time is over, you are getting rewarded with other properties (gold, energy, diamonds). For example, you can buy an apple for 50gold, It takes a minute, you get rewarded with 75energy. Or if you take a run, it cost 50energy, it takes 5minutes, reward is 25gold and 25silver. These definitions is what i call actions. Currently I already have a system where this already works and I can define as much actions with as much properties as I want. The definitions I have kinda looks like this: {id:101, category:544, onInit:{gold:-75}, onComplete:{energy:75}, time:2000, name:"Apple", locked: false} {id:102, category:544, onInit:{gold:-135}, onComplete:{energy:145}, time:2000, name:"Banana", locked: false} {id:106, category:302, onInit:{energy:-50, power: -25}, onComplete:{gold:100, diamonds:2}, time:10000, name:"Run", locked: false} {id:107, category:302, onInit:{energy:-70, silver: -55}, onComplete:{gold:100}, time:10000, name:"Dance", locked: false} {id:108, category:302, onInit:{energy:-230, power: -355}, onComplete:{gold:70, silver:70}, time:10000, name:"Fitness", locked: false} Now, I would love to add a system where I can lock/unlock the actions using achievement rules. Lets say, if you buy 10 apples, you unlock a new action, like bananas which cost more, and reward more. In the future I maybe want to restrict achievements and actions to levels. I am kinda stuck how to structure this. I have 2 questions: Which patterns are used to define achievements? How/where are they defined? Should it be part of the action, or should it be a separate controller? Is it a good idea to register all completed actions to it? I think I want multiple types of achievement rules, Id love to hear some ideas how to develop it. How do you create/find a good balance, so the user does not get stuck or can cheat by repeat a pattern of actions to get too much rewards. I know there is not a simple answer and i'm lacking of a good game-concept, but I wonder if anyone created such a game and how you dealed and played with it.

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• Sweden Azure Group with Michele Laroux Bustamente &amp; Maartin Balliauw Thursday 22nd May

  - by Alan Smith

  Originally posted on: http://geekswithblogs.net/asmith/archive/2014/05/19/156418.aspxSweden Azure Group (SWAG) has the privilege of welcoming Michele Laroux Bustamente and Maartin Balliauw to present sessions at our meeting this Thursday. Michele and Maartin are two of the world’s leading experts in Cloud Computing and Azure, and will be taking time out from their busy schedules to share their ideas with us, and answer any questions. Knowit Stockholm are kindly hosting the event at their offices, and providing food and refreshments. It should be a great evening. You can register for the event here. Azure Q & A - Michele Leroux Bustamante In this interactive Q & A session Michele Leroux Bustamante will be on hand to share her wealth of experience on Azure related issues. If you are new to Azure and wanting some tips to get started, or an experienced developer needing to negotiate the legal and political protocols related to Cloud Computing Michele will have been there, done that, and be willing to share her experiences. This session will be entirely driven by that attendees, so please come prepared with questions. Reducing latency on the web with the Windows Azure CDN – Maarten Balliauw Serving up content on the Internet is something our web sites do daily. But are we doing this in the fastest way possible? How are users in faraway countries experiencing our apps? Why do we have three webservers serving the same content over and over again? In this session, we’ll explore the Windows Azure Content Delivery Network or CDN, a service which makes it easy to serve up blobs, videos and other content from servers close to our users. We’ll explore simple file serving as well as some more advanced, dynamic edge caching scenarios. Michele Leroux Bustamante Michele Leroux Bustamante is CIO at Solliance (solliance.net), cofounder of Snapboard (snapboard.com), and is recognized as a Microsoft Regional Director and MVP. Michele is a thought leader with over 20 years specializing in building scalable and secure end-to-end system design, identity and access management, and cloud computing technologies – for companies of all sizes. In recent years Michele has also helped launch several startup business ventures and has been a mentor to startups in several accelerator programs – providing both technical and business guidance. Michele shares her experiences through presentations and keynotes all over the world, and has been publishing regularly in technology journals. Maarten Balliauw Maarten Balliauw is a Technical Evangelist at JetBrains. His interests are all web: ASP.NET MVC, PHP and Windows Azure. He’s a Microsoft Most Valuable Professional (MVP) for Azure and an ASPInsider. He has published many articles in both PHP and .NET literature such as MSDN magazine and PHP architect. Maarten is a frequent speaker at various national and international events such as MIX (Las Vegas), TechDays, DPC, …

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• Euler angles to Cartesian Coordinates for use with gluLookAt

  - by notrodash

  I have searched all of the internet but just couldn't find the answer. I am using LibGDX and this is part of my code that loops over and over: public void render() { GL11 gl = Gdx.gl11; float centerX = (float)Math.cos(yaw) * (float)Math.cos(pitch); float centerY = (float)Math.sin(yaw) * (float)Math.cos(pitch); float centerZ = (float)Math.sin(pitch); System.out.println(centerX+" "+centerY+" "+centerZ+" ~ "+GDXRacing.camera.position.x+" "+GDXRacing.camera.position.y+" "+GDXRacing.camera.position.z); Gdx.glu.gluLookAt(gl, GDXRacing.camera.position.x, GDXRacing.camera.position.y, GDXRacing.camera.position.z, centerX, centerY, centerZ, 0, 1, 0); if(Gdx.input.isKeyPressed(Keys.A)) { yaw--; } if(Gdx.input.isKeyPressed(Keys.D)) { yaw++; } } I might just be bad at the math, but I dont get it. Does someone have a good explanation and an idea about how to deal with this? I am trying to make a first person camera. By the way, the camera is translated by +10 on the Z axis. Currently when I run the application, this is what I get: Watch video in browser | Download video (for those who cant download the video, everything shakes in a clockwise/anticlockwise action, depending on if I increase or decrease the Yaw value) -Thank you. [edit] and with this code: public void render() { GL11 gl = Gdx.gl11; float centerX = (float)(MathUtils.cosDeg(yaw)*4); float centerY = 0; float centerZ = (float)(MathUtils.sinDeg(yaw)*4); System.out.println(centerX+" "+centerY+" "+centerZ+" ~ "+GDXRacing.camera.position.x+" "+GDXRacing.camera.position.y+" "+GDXRacing.camera.position.z); Gdx.glu.gluLookAt(gl, GDXRacing.camera.position.x, GDXRacing.camera.position.y, GDXRacing.camera.position.z, centerX, centerY, centerZ, 0, 1, 0); if(Gdx.input.isKeyPressed(Keys.A)) { yaw--; } if(Gdx.input.isKeyPressed(Keys.D)) { yaw++; } } it slowly swings from the left to the right. This approach worked for turning left and right for 2d games though. What am I doing wrong?

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• #SSAS #Tabular Workshop and Community Events in Netherlands and Denmark

  - by Marco Russo (SQLBI)

  Next week I will finally start the roadshow of the SSAS Tabular Workshop, a 2-day seminar about the new BISM Tabular model for Analysis Services that has been introduced in SQL Server 2012. During these roadshows, we always try to arrange some speeches at local community events in the evening - we already defined for Copenhagen, we have some logistic issue in Amsterdam that we're trying to solve. Here is the timetable: Netherlands SSAS Workshop in Amsterdam, NL – April 16-17, 2012 2-day seminar, I and Alberto will be the trainers for this event, register here We're trying to manage a Community event but we still don't have a confirmation, stay tuned        Denmark SSAS Workshop in Copenhagen, DK – April 26-27, 2012 2-day seminar, I and Alberto will be the trainers for this event, register here Community event on April 26, 2012 This event will run in Hellerup, at Microsoft venue All details available here: http://msbip.dk/events/26/msbip-mode-nr-5/ People from Sweden are welcome! Just register to this private group on LinkedIn in order to announce your presence, so we’ll know how many people will attend In community events we’ll deliver two speeches – here are the descriptions: Inside xVelocity (VertiPaq) PowerPivot and BISM Tabular models in Analysis Services share a great columnar-based database engine called xVelocity in-memory analytics engine (VertiPaq). If you want to improve performance and optimize memory used, you have to understand some basic principles about how this engine works, how data is compressed, and how you can design a data model for better optimization. Prepare yourself to change your mind. xVelocity optimization techniques might seem counterintuitive and are absolutely different than OLAP and SQL ones! Choosing between Tabular and Multidimensional You have a new project and you have to make an important decision upfront. Should you use Tabular or Multidimensional? It is not easy to answer, because sometime there is a clear choice, but most of the times both decisions might be correct, at least at the beginning. In this session we’ll help you making an informed decision, correctly evaluating pros and cons of each one according to common scenarios, considering both short-term and long-term consequences of your choice. I hope to meet many people in this first dates. We have many other events coming in May and June, including an online event (for US time zones), and you can also attend our PreCon Day at TechEd US in Orland (PRC06) or TechEd Europe in Amsterdam. I’ll be a good customer for airline companies in the next three months! I’m just sorry that I hadn’t time to write other articles in the last month, but I’m accumulating material that I will need to write down during some flight – stay tuned…

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• Class instance clustering in object reference graph for multi-entries serialization

  - by Juh_

  My question is on the best way to cluster a graph of class instances (i.e. objects, the graph nodes) linked by object references (the -directed- edges of the graph) around specifically marked objects. To explain better my question, let me explain my motivation: I currently use a moderately complex system to serialize the data used in my projects: "marked" objects have a specific attributes which stores a "saving entry": the path to an associated file on disc (but it could be done for any storage type providing the suitable interface) Those object can then be serialized automatically (eg: obj.save()) The serialization of a marked object 'a' contains implicitly all objects 'b' for which 'a' has a reference to, directly s.t: a.b = b, or indirectly s.t.: a.c.b = b for some object 'c' This is very simple and basically define specific storage entries to specific objects. I have then "container" type objects that: can be serialized similarly (in fact their are or can-be "marked") they don't serialize in their storage entries the "marked" objects (with direct reference): if a and a.b are both marked, a.save() calls b.save() and stores a.b = storage_entry(b) So, if I serialize 'a', it will serialize automatically all objects that can be reached from 'a' through the object reference graph, possibly in multiples entries. That is what I want, and is usually provides the functionalities I need. However, it is very ad-hoc and there are some structural limitations to this approach: the multi-entry saving can only works through direct connections in "container" objects, and there are situations with undefined behavior such as if two "marked" objects 'a'and 'b' both have a reference to an unmarked object 'c'. In this case my system will stores 'c' in both 'a' and 'b' making an implicit copy which not only double the storage size, but also change the object reference graph after re-loading. I am thinking of generalizing the process. Apart for the practical questions on implementation (I am coding in python, and use Pickle to serialize my objects), there is a general question on the way to attach (cluster) unmarked objects to marked ones. So, my questions are: What are the important issues that should be considered? Basically why not just use any graph parsing algorithm with the "attach to last marked node" behavior. Is there any work done on this problem, practical or theoretical, that I should be aware of? Note: I added the tag graph-database because I think the answer might come from that fields, even if the question is not.

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• Do I need to create my own or use a commercial server for the features and matchmaking options I want my game to support?

  - by baptzmoffire

  So I'm developing an indie turn-based game for iOS and, in coding up a Game Center matchmaking class, I'm starting to question whether Game Center is even the best choice for what I want this game to do. I need to figure out whether I need to create my own server, invest in a preexisting client or server service, or if I even need to use a server at all. If I do need to use a ready-made service other than Game Center, which server would accomodate my game's needs best? I have limited resources and funds. Here is the list of features I want my game to support, ideally: Turn-based gameplay (a la "with Friends" and "with Buddies" games) Smart matchmaking (matching users up with other players of comparable skill/achievements) Random matchmaking Facebook matchmaking Specific username matchmaking Contact list matchmaking A way to select what "type" of match you want to challenge an opponent to. (In random, smart, and Facebook matchmaking, there will be different "wagers" the player can make. [e.g. "I wanna play a random opponent for 1000 points. Now, I wanna play my Facebook buddy for 1,000,000 points."] There will be a predetermined range of amounts you can play for. It won't be customizable.) Buddies list capability (Game-buddies, as opposed to contacts and Facebook) A higher concurrent game cap than Game Center offers (which I still can't really find a straight answer on) Scalability (it should support 2 or 20,000,000 players) Objective-C compatibility Flexibility (for all the stuff I haven't thought of yet) Am I dreaming, here? Is there even a service that can handle all of these features? Do I need to invest months in learning a networking language to build my own? If so, how much would I need to spend on hardware? I've been looking around all morning and, so far, the only seemingly viable option is SmartFox. Under "Everything and the kitchen sink" section here, it says they support "virtual world with Zones, Rooms and RoomGroups, create complex game challenges, send invitations, manage buddy lists, create custom permission profiles, oversee the security aspects and tons more." http://www.smartfoxserver.com/overview/platform Is there an option that Im just overlooking? Thanks for any help anyone can provide. Sorry for the long poast. One last question: Does anyone know which server Dice with Buddies uses? I was experimenting with how many concurrent games I could get going and my ADHD kicked in at about 80 games. 80 concurrent games would be great for my game, but again, I need the other features I mentioned too. Thanks again.

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• 3D terrain map with Hexagon Grids (XNA)

  - by Rob

  I'm working on a hobby project (I'm a web/backend developer by day) and I want to create a 3D Tile (terrain) engine. I'm using XNA, but I can use MonoGame, OpenGL, or straight DirectX, so the answer does not have to be XNA specific. I'm more looking for some high level advice on how to approach this problem. I know about creating height maps and such, there are thousands of references out there on the net for that, this is a bit more specific. I'm more concerned with is the approach to get a 3D hexagon tile grid out of my terrain (since the terrain, and all 3d objects, are basically triangles). The first approach I thought about is to basically draw the triangles on the screen in the following order (blue numbers) to give me the triangles for terrain (black triangles) and then make hexes out of the triangles (red hex). http://screencast.com/t/ebrH2g5V This approach seems complicated to me since i'm basically having to draw 4 different types of triangles. The next approach I thought of was to use the existing triangles like I did for a square grid and get my hexes from 6 triangles as follows http://screencast.com/t/w9b7qKzVJtb8 This seems like the easier approach to me since there are only 2 types of triangles (i would have to play with the heights and widths to get a "perfect" hexagon, but the idea is the same. So I'm looking for: 1) Any suggestions on which approach I should take, and why. 2) How would I translate mouse position to a hexagon grid position (especially when moving the camera around), for example in the second image if the mouse pointer were the green circle, how would I determine to highlight that hexagon and then translating that into grid coordinates (assuming it is 0,0)? 3) Any references, articles, books, etc - to get me going in the right direction. Note: I've done hex grid's and mouse-grid coordinate conversion before in 2d. looking for some pointers on how to do the same in 3d. The result I would like to achieve is something similar to the following: http :// www. youtube .com / watch?v=Ri92YkyC3fw (sorry about the youtube link, but it will only let me post 2 links in this post... same rep problem i mention below...) Thanks for any help! P.S. Sorry for not posting the images inline, I apparently don't have enough rep on this stack exchange site.

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• External hard drive not recognized

  - by sr71

  Installed Ubuntu 10.10 on a hard drive by itself (no windows). All updates are up to date. Everything`works fine except when I plug in a 320 gig Toshiba external hard drive....it is not recognized. When I plug in an 8 gig flash drive it is recognized no problem. What do I mean by "not recognized"? I mean: how do you know it was not recognized. You can check the command "cat /proc/partitions" in a terminal with and without the hdd attached. If you see some difference, it's ok. If the difference is something like "sda1" (sd+letter+number) then you have partition on it, maybe it can't be handled in Ubuntu (no filesystem on it or so). If there is only "sda" in the difference for example (sd+letter, but no number after it) then the drive itself is detected, just no partition is created on it. Also you can check out the messages of the kernel, with the "dmesg" command in the terminal. If there is no disk/partition/anything in /proc/partitions, there can be an USB level problem, you can issue command "lsusb" as it was suggested before my answer. It's really matter of what do you mean about "not recognized". @Marco Ceppi @Oli @Pitto By "not recognized" I meant that when I plug in a 8 gig flash drive an icon immediately appears on the desktop imdicating that there is a flash drive plugged in and I can click on it and view the files on the flash drive. It also shows up on the "Nautilus" default file manager. When I plug in the 320 gig Toshiba external hard drive, I get no indication on the desktop or the file manager (thus "not recogized"). When I run the command cat/proc/partitions/ I get an error message Could not open location 'file:///home/bob/cat/proc/partitions' with or without the external hard drive installed. With the dmeg command I get about 10 pages of info with no mention of disk/partition/anything in /proc/partitions. When I run lsusb command I get the following: bob@bob-desktop:~$ lsusb Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 003 Device 003: ID 04b3:3003 IBM Corp. Rapid Access III Keyboard Bus 003 Device 002: ID 04b3:3004 IBM Corp. Media Access Pro Keyboard Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

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• Phone number in meta description bad or good for local rankings NAP

  - by bybe

  Once again I'm at it with increasing people's local rankings and I've learnt so much about local rankings in the past 2 weeks it feels like my brain is gonna pop anyway, question is fairly simple for someone who engages in local rankings and I appreciate the question may be a little guess work but isn't SEO mostly guessing anyway? From what I've read and learned that Google works of a system called nap for local rankings (With many other factors but this question is purely based on NAP). For people who care about local rankings NAP stands for Name of Business / Address of Business / Phone Number for Business. Now what what I've read you don't need the whole NAP to be on one website, a P or just a N can help towards your local rankings. It's believed that NAP rewards more than just P and N for example but knowing Google they might have a diversity checker which is my concern what your get to in a moment. Now of course sites weight differently where your business is posted, it's certainly going to be more credible if your NAP details are on your national phone book than say a blog site, so taking in this consideration too. Pure Guess (Not apart of the question but none the less makes a good read on my belief). Now my guess work would make me believe that the formula would look something like (N)+(A)+(P)x(T) So (N)name would be 1 or 0 to indicate present or not So (A)dress would be 1 or 0 to indicate present or not So (P)hone would be 1 or 0 to indicate present or not So (T)rust would be 1-100 to indicate level of trust So a phone number appearing on youtube might look something like 0+0+1x95= 95 and a NAP appearing on your national phone book might look something like 1+1+1x100= 300 Please note that I'm not saying this is the sole factor and I'm sure its way more complex that this with things like other factors on the page, off the page (Reviews, Links, Clicks) and so on but its still a contributor). The Question My question is fairly simple and I'd imagine hard to impossible to have an actual definite answer to this but maybe someone has seen official wording else where on this, is it bad to include address or phone number in the Meta Description? The reason I ask is that one of my competitors has these elements in the meta descriptions and their local rankings are absolutely superb, the problem I have with this is scrap bot sites like 'Similar Too' 'Seo Rankings' and 1,000's of the other scrap box networks that scrap site and then make urls with your site information are mostly limited to your meta description what this means that your phone number, address and sometimes even your company name if the domain is exact will appear as AP, and even NAP on thousands of websites. So, is it a bad strategy to include phone number and address in meta description, everything I read into would suggest its good of course with the downside of maybe lowering quality of description for click thoughts but top rankings would increase this 10 folds anyhow..

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• Programming Language, Turing Completeness and Turing Machine

  - by Amumu

  A programming language is said to be Turing Completeness if it can successfully simulate a universal TM. Let's take functional programming language for example. In functional programming, function has highest priority over anything. You can pass functions around like any primitives or objects. This is called first class function. In functional programming, your function does not produce side effect i.e. output strings onto screen, change the state of variables outside of its scope. Each function has a copy of its own objects if the objects are passed from the outside, and the copied objects are returned once the function finishes its job. Each function written purely in functional style is completely independent to anything outside of it. Thus, the complexity of the overall system is reduced. This is referred as referential transparency. In functional programming, each function can have its local variables kept its values even after the function exits. This is done by the garbage collector. The value can be reused the next time the function is called again. This is called memoization. A function usually should solve only one thing. It should model only one algorithm to answer a problem. Do you think that a function in a functional language with above properties simulate a Turing Machines? Functions (= algorithms = Turing Machines) are able to be passed around as input and returned as output. TM also accepts and simulate other TMs Memoization models the set of states of a Turing Machine. The memorized variables can be used to determine states of a TM (i.e. which lines to execute, what behavior should it take in a give state ...). Also, you can use memoization to simulate your internal tape storage. In language like C/C++, when a function exits, you lose all of its internal data (unless you store it elsewhere outside of its scope). The set of symbols are the set of all strings in a programming language, which is the higher level and human-readable version of machine code (opcode) Start state is the beginning of the function. However, with memoization, start state can be determined by memoization or if you want, switch/if-else statement in imperative programming language. But then, you can't Final accepting state when the function returns a value, or rejects if an exception happens. Thus, the function (= algorithm = TM) is decidable. Otherwise, it's undecidable. I'm not sure about this. What do you think? Is my thinking true on all of this? The reason I bring function in functional programming because I think it's closer to the idea of TM. What experience with other programming languages do you have which make you feel the idea of TM and the ideas of Computer Science in general? Can you specify how you think?

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• What is the difference between development and R&D?

  - by MainMa

  I was asked by a colleague to explain clearly the difference between ordinary development and research and development (R&D) and was unable to do it. After reading Wikipedia, I still don't have the precise answer. According to Wikipedia (slightly modified): There are two primary models: In one model, the primary function is to develop new products; in the other model, the primary function is to discover and create new knowledge about scientific and technological topics for the purpose of uncovering and enabling development of valuable new products, processes, and services. The first model is confusing. Does it mean that development (not R&D) consists exclusively in adding new features to a product, solving bugs and doing maintenance? What if something which was previously developed as a new feature becomes a separate product? The second model is less confusing, but still, how to qualify whether something is new knowledge or existent knowledge which is just rediscovered? Later, Wikipedia adds that ordinary development is different from R&D because of its: nearly immediate profit or immediate improvement. It's still not clear enough. How to qualify "nearly immediate profit"? What if a task has an immediate profit but requires heavy research? Or if it is basic but has uncertain profit, like the enforcement of a common style over the codebase? For example, does it belong to development or R&D to: Develop an engine which abstracts the access to the database, simplifying and shortening enormously the code of other applications (existent or ones which will be written in future) which should access to the database? Establish a new service-oriented architecture for the entire organization of company resources, in order to move from a bunch of separate and autonomous applications to a set of well-organized, interconnected web services, like what is used by Amazon? Design a new communication protocol to allow faster replication of data between two data centers of the company? Conceive a new type of software testing while working on a specific product, knowing that this type of testing will improve/simplify the testing process? Prove that Functional programming is more appropriate than OOP for a specific application, based on evidence, logic and previous experience? Enhance the existent application by adding gestures on tactile screens, after doing studies and testing that shows that those gestures improve the productivity of the users by a ratio of at least 1.4 for a precise set of tasks? Find a way to strongly enhance the Power usage effectiveness (PUE) of a data center? Create a Domain-Specific Language (DSL)? In short, how could I determine whether I'm doing R&D while working on something?

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• WebAPI and MVC4 and OData

  - by Aligned

  I was looking closer into WebAPI, specificially how to use OData to avoid writing GetCustomerByCustomerId(int id) methods all over the place. I had problems just returning IQueryable<T> as some sites suggested in the WebpAPI (Assembly System.Web.Http.dll, v4.0.0.0).  I think things changed in the release version and the blog posts are still out of date. There is no [Queraable] as the answer to this question suggests. Once I get WebAPI.Odata Nuget package, and added the [Queryable] to the method http://localhost:57146/api/values/?$filter=Id%20eq%201 worked (don’t forget the ‘$’). Now the main question is whether I should do this and how to stop logged in users from sniffing the url and getting data for other users. I John V. Peterson has a post on securing WebAPI with headers and intercepting the call at that point. He had an update to use HttpMessageHandlers instead. I think I’ll use this to force the call to contain some kind of unique code for the user, but I’m still thinking about this. I will not expose this to the public, just to my calls with-in my Forms Authentication areas. Other links: http://robbincremers.me/2012/02/16/building-and-consuming-rest-services-with-asp-net-web-api-and-odata-support/ ~lots of good information John V Peterson example: https://github.com/johnvpetersen/ASPWebAPIExample ~ all data access goes through the WebApi and the web client doesn’t have a connection string ~ There is code library for calling the WebApi from MVC using the HttpClient. It’s a great starting point http://blogs.msdn.com/b/alexj/archive/2012/08/15/odata-support-in-asp-net-web-api.aspx ~ Beta (9/18/2012) Nuget package to help with what I want to do? ~ has a sample code project with examples http://blogs.msdn.com/b/alexj/archive/2012/08/15/odata-support-in-asp-net-web-api.aspx http://blogs.msdn.com/b/alexj/archive/2012/08/21/web-api-queryable-current-support-and-tentative-roadmap.aspx http://stackoverflow.com/questions/10885868/asp-net-mvc4-rc-web-api-odata-filter-not-working-with-iqueryable JSON, pass the correct format in the header (Accept: application/json). $format=JSON doesn’t appear to be working. Async methods built into WebApi! Look for the GetAsync methods.

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• No network connectivity (not wired or wireless) - RT5390

  - by Ben Udy

  I am starting to think I simply need to accept a small loss and sell my new ASUS K73E. Because I really don't enjoy computing when I have to deal with Windough$ and this windows 7 64 bit on my new ASUS is even worse than the old machines with XP. I have written to ASUS and they simply say "We don't support Linux" and while Ralink's website says they do support Linux I can't get anyone to tell me what model Ralink card might be in my machine. Is anyone out there who might be able to give me some useful advice???? Here is the answer to command lspci nn && lsusb && lsmod && rfkill list all: di,snd_seq snd 54244 16 snd_hda_codec_realtek,snd_hda_intel,snd_hda_codec,snd_hwdep,snd_pcm_oss,snd_mixer_oss,snd_pcm,snd_seq_oss,snd_rawmidi,snd_seq,snd_timer,snd_seq_device uvcvideo 57374 0 videodev 34361 1 uvcvideo v4l1_compat 13251 2 uvcvideo,videodev soundcore 6620 1 snd snd_page_alloc 7076 2 snd_hda_intel,snd_pcm psmouse 63677 0 serio_raw 3978 0 lp 7028 0 parport 32635 2 ppdev,lp fbcon 35102 71 tileblit 1999 1 fbcon font 7557 1 fbcon bitblit 4707 1 fbcon softcursor 1189 1 bitblit video 17375 0 output 1871 1 video vga16fb 11385 1 vgastate 8961 1 vga16fb ahci 32360 2 di,snd_seq snd 54244 16 snd_hda_codec_realtek,snd_hda_intel,snd_hda_codec,snd_hwdep,snd_pcm_oss,snd_mixer_oss,snd_pcm,snd_seq_oss,snd_rawmidi,snd_seq,snd_timer,snd_seq_device uvcvideo 57374 0 videodev 34361 1 uvcvideo v4l1_compat 13251 2 uvcvideo,videodev soundcore 6620 1 snd snd_page_alloc 7076 2 snd_hda_intel,snd_pcm psmouse 63677 0 serio_raw 3978 0 lp 7028 0 parport 32635 2 ppdev,lp fbcon 35102 71 tileblit 1999 1 fbcon font 7557 1 fbcon bitblit 4707 1 fbcon softcursor 1189 1 bitblit video 17375 0 output 1871 1 video vga16fb 11385 1 vgastate 8961 1 vga16fb ahci 32360 2 Edit #2 lspci 00:00.0 Host bridge: Intel Corporation Device 0104 (rev 09) 00:02.0 VGA compatible controller: Intel Corporation Device 0116 (rev 09) 00:16.0 Communication controller: Intel Corporation Cougar Point HECI Controller #1 (rev 04) 00:1a.0 USB Controller: Intel Corporation Cougar Point USB Enhanced Host Controller #2 (rev 05) 00:1b.0 Audio device: Intel Corporation Cougar Point High Definition Audio Controller (rev 05) 00:1c.0 PCI bridge: Intel Corporation Cougar Point PCI Express Root Port 1 (rev b5) 00:1c.1 PCI bridge: Intel Corporation Cougar Point PCI Express Root Port 2 (rev b5) 00:1c.5 PCI bridge: Intel Corporation Cougar Point PCI Express Root Port 6 (rev b5) 00:1d.0 USB Controller: Intel Corporation Cougar Point USB Enhanced Host Controller #1 (rev 05) 00:1f.0 ISA bridge: Intel Corporation Device 1c49 (rev 05) 00:1f.2 SATA controller: Intel Corporation Cougar Point 6 port SATA AHCI Controller (rev 05) 00:1f.3 SMBus: Intel Corporation Cougar Point SMBus Controller (rev 05) 02:00.0 Network controller: RaLink Device 5390 03:00.0 Ethernet controller: Atheros Communications Device 1083 (rev c0) lsusb Bus 002 Device 002: ID 8087:0024 Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 001 Device 003: ID 13d3:5710 IMC Networks Bus 001 Device 002: ID 8087:0024 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Thanks for the suggestion because this gave me a model for Ralink RT5390. I have now gone to Ralink.com and downloaded (via Windows 7) the driver package (it is a bz2 file). I hope I can figure out how to install it. And FYI - I was not able to run su (not authorized?) and dmidecode didn't exist (probably needs to be downloaded BUT no internet yet in Ubuntu)

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• Registering domain during christmas holydays

  - by arkascha

  One of the domain names I tried to register previously has been blocked by a domain grabber two days prior to my own attempt. That was about 1 year ago. The attempt to buy the domain from that person failed due to a totally exaggerated price. So I dropped the issue and watched the domain (offered at sedo.com). As expected there were no more offers, the domain was not sold. Now I learn from the whois database that the registration of that domain name ends on 25.12.2012 (christmas holyday). This raises two questions for me, I fail to find reliable answers on the internet. So maybe someone experienced here can drop a statement or a hint: is it reasonable that the domain name in question really will be free again when that date mentioned in the whois database up to when the domain is registered has passed? I certainly know that the registration can be prolonged, that is not what I mean. I expect (hope) that that domain grabber does not extend the registration, since it costs money and effort and he failed to sell the domain. Provided this is the case and the domain registration is not prolonged, is that date mentioned reliable? Or might it just be some 'default' date? I would like to try to register that domain name as soon as it is unregistered. Since that domain grabber registered that domain only two days before my own registration attempt I would like to prevent such annoying interference next time. So I ask myself: is it possible to register a domain name on a holyday? I mean not to send an email to my provider to do so on that day or before, but to actually have to process taking place as not to wait for 1-2 days after the unregistration? My own provider which I am very happy with does not offer such service on a holyday (which is perfectly understandable). They are 'still checking' if they can offer something automatic. I researched and did not find an answer to the question if that is possible at all. Is an autoomatic registration attempt on a holyday possible? Where can I do that? Is that reliable? Thanks for any reply!

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• ASP.NET Web Forms is bad, or what am I missing?

  - by iveqy

  Being a PHP guy myself I recently had to write a spider to an asp.net site. I was really surprised by the different approach to ajax and form-handling. For example, in the PHP sites I've worked with, a deletion of a database entry would be something like: GET delete.php?id=&confirm=yes and get a "success" back in some form (in the ajax case, probably a json reply). In this asp.net application you would instead post a form, including all inputs on the page, with a huge __VIEWSTATE and __EVENTVALIDATION. This would be more than 10 times as big as above. The reply would be the complete side again, with a footer containing some structured data for javascript to parse and display the result. Again, the whole page is sent, and then throwed away(?) since it's already displayed. Why not just send the footer with the data to parse (it's not json nor xml but a | separated list). I really can't see why you would design a system that way. Usually you've a fast client, and a somewhat fast server but a really slow connection. Why not keep the datatransfer to a minimum? Why those huge __VIEWSTATE and __EVENTVALIDATION? It seems that everything is done way to chatty and way to complicated. I really can't see the point and that usually means that I'm missing something. So please tell me, what are the reasons for this design and what benefits (and weaknesses) does it have? (Yes I know that __VIEWSTATE is used to tell what type of form-konfiguration should be sent back to the server. But WHY is this needed?) Please keep this discussion strictly technical and avoid flamewars. Update: Please excuse the somewhat rantish question. I tried to explain my view to be able to get a better answer. I am not saying that asp.net is bad, I am saying that I don't understand the meaning of those concepts. Usually that means that I've things to learn instead of the concepts beeing wrong. I appreciate the explanations about that "you don't have to do this way in asp.net", I'll read up on MVC and other .net technologies. However, there most be a reason for this site (the one I referred to) to be written the way it is. It's written by professionals for a big organisation with far more experience than what I've. Any explanation about their (possible) design choice would be welcome.

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• Understanding clojure keywords

  - by tjb1982

  I'm taking my first steps with Clojure. Otherwise, I'm somewhat competent with JavaScript, Python, Java, and a little C. I was reading this artical that describes destructuring vectors and maps. E.g. => (def point [0 0]) => (let [[x y] point] => (println "the coordinates are:" x y)) the coordinates are: 0 0 but I'm having a difficult time understanding keywords. At first glance, they seem really simple, as they just evaluate to themselves: => :test :test But they seem to be used is so many different ways and I don't understand how to think about them. E.g., you can also do stuff like this: => (defn full-name [& {first :first last :last}] => (println first last)) => (full-name :first "Tom" :last "Brennan") Tom Brennan nil This doesn't seem intuitive to me. I would have guessed the arguments should have been something more like: (full-name {:first "Tom" :last "Brennan"}) because it looks like in the function definition that you're saying "no required arguments, but a variable number of arguments comes in the form of a single map". But it seems more like you're saying "no required arguments, but a variable number of arguments comes which should be a list of alternating keywords and values... ?" I'm not really sure how to wrap my brain around this. Also, things like this confuse me too: => (def population {:humans 5 :zombies 1000}) => (:zombies population) 1000 => (population :zombies) 1000 How do maps and keywords suddenly become functions? If I could get some clarification on the use of keywords in these two examples, that would be really helpful. Update I've also seen http://stackoverflow.com/questions/3337888/clojure-named-arguments and while the accepted answer is a great demonstration of how to use keywords with destructuring and named arguments, I'm really looking more for understanding how to think about them--why the language is designed this way and how I can best internalize their use.

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• Server-infrastructure recommendations

  - by Tim van Elsloo

  Here's the thing: I need a cheap, fast, reliable infrastructure that can dynamically scale (like Amazon S3: cloud-storage). I'm thinking of 3 different type of 'servers'. Application-server Should be able to run CentOS (or another light Linux-distr.) Should be able to run Apache Should be able to run PHP Should be able to run GD (so it does rely on it's cpu). Should be extremely reliable and fast. Database-server Should be able to run MySQL Should be able to... well, do nothing else :P. Should be extremely reliable and fast. Storage-server Should be able to run some kind of file-transfer-deamon (like FTP, CouchDB, etc.) Should be able to do nothing else. Should be extremely reliable and fast. So technically, by transferring all static data to 2 different servers/services, the application-server can totally focus on the webpages. My questions: What services do you recommend? Which is cheaper, faster and more reliable: using my own server, or using some cloud-storage/cloud-computing-service (like Amazon S3, CloudFiles, etc.)? How can I prevent bandwidth abuse (such as dos-attacks causing the bill to be extremely high)? What's the difference between "including CDN" and "excluding CDN"? It seems the price doesn't differ at CloudFiles? Do you have to pay "including CDN" + "excluding CDN" when you decide to enable the delivery-network? Or have you only got to pay "including CDN"? Should I use my own nameserver too or can I use my domain-hoster's nameservers? What are the minimum software specifications of a nameserver. Can I write some software myself? Does anyone have a good protocol-description? I hope you can answer my questions. Answers I shouldn't write my own nameserver-software. Instead, I should use something like bind. (http://osspro.com/2010/05/04/linux-create-your-own-domain-name-server-dns/).

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• How to discriminate from two nodes with identical frequencies in a Huffman's tree?

  - by Omega

  Still on my quest to compress/decompress files with a Java implementation of Huffman's coding (http://en.wikipedia.org/wiki/Huffman_coding) for a school assignment. From the Wikipedia page, I quote: Create a leaf node for each symbol and add it to the priority queue. While there is more than one node in the queue: Remove the two nodes of highest priority (lowest probability) from the queue Create a new internal node with these two nodes as children and with probability equal to the sum of the two nodes' probabilities. Add the new node to the queue. The remaining node is the root node and the tree is complete. Now, emphasis: Remove the two nodes of highest priority (lowest probability) from the queue Create a new internal node with these two nodes as children and with probability equal to the sum of the two nodes' probabilities. So I have to take two nodes with the lowest frequency. What if there are multiple nodes with the same low frequency? How do I discriminate which one to use? The reason I ask this is because Wikipedia has this image: And I wanted to see if my Huffman's tree was the same. I created a file with the following content: aaaaeeee nnttmmiihhssfffouxprl And this was the result: Doesn't look so bad. But there clearly are some differences when multiple nodes have the same frequency. My questions are the following: What is Wikipedia's image doing to discriminate the nodes with the same frequency? Is my tree wrong? (Is Wikipedia's image method the one and only answer?) I guess there is one specific and strict way to do this, because for our school assignment, files that have been compressed by my program should be able to be decompressed by other classmate's programs - so there must be a "standard" or "unique" way to do it. But I'm a bit lost with that. My code is rather straightforward. It literally just follows Wikipedia's listed steps. The way my code extracts the two nodes with the lowest frequency from the queue is to iterate all nodes and if the current node has a lower frequency than any of the two "smallest" known nodes so far, then it replaces the highest one. Just like that.

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