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• How should I structure my database to gain maximum efficiently in this scenario?

  - by Bob Jansen

  I'm developing a PHP script that analyzes the web traffic of my clients websites. By placing a link to a javascript on the clients website (think of Google Analyses), my script harvests information like: the visitors IP address, reference link, current page link, user agent, etc. Now my clients can view these statistics via a control panel that I have build. These clients can also adjust profile settings, set firewall rules, create support tickets and pay invoices. Currently all the the traffic is stored in one table. You can imagine that this tabel would become very large as some my clients receive thousands of pageviews per day. Furthermore, all the traffic data of each client would be stored in the same table, creating a mess. This is the same for the firewall rules currently, and the invoice and support system. I'm looking for way to structure my database in a more organized way to hold large amounts of data of multiple users. This is the first project that I'm developing that deals with so much data, and would like to hear suggestions and tips. I was thinking of using multiple databases to structure the data. The main database will store users data (email,pass,id,etc) admin/website settings. Than each client will have an unique database labeled prefix_userid, which carry tables holding their traffic, invoice, and support ticket data. Would this be a solution, and would it slow down or speed up overall performances (that is spreading the data over muliple databases). I have a solid VPS, but would like to safe and be as effient as possible.

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• Custom graph comparison?

  - by user57828

  I'm trying to compare two graphs using hash value ( i.e, at the time of comparison, try to avoid traversing the graph ) Is there a way to make a function such that the hash values compared can also lead to determining at which height the graphs differ? The comparisons between two graphs are to be made by comparing children at a certain level. One way to compare the graphs is have a final hash value for the root node and compare them, but that wouldn't directly reflect at which level the graphs differ, since their immediate children might be the same ( or any other case ).

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• initial Class design: access modifiers and no-arg constructors

  - by yas

  Context: Student working through Class design in personal/side project for Summer. I've never written anything implemented by others or had to maintain code. Trying to maximize encapsulation and imagining what would make code easy to maintain. Concept: Tight/Loose Class design where Tight and Loose refer to access modifiers and constructors. Tight: initially, everything, including setters, is private and a no-arg constructor is not provided (only a full constructor). Loose: not Tight Exceptions: the obvious like toString Reasoning: If code, at the very beginning, is tight, then it should be guaranteed that changes, with respect to access/creation, should never damage existing implementations. The loosening of code happens incrementally and must be thought through, justified, and safe (validated). Benefit: Existing implementing code should not break if changes are made later. Cost: Takes more time to create. Since this is my own thinking, I hope to get feedback as to whether I should push to work this way. Good idea or bad idea?

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• Strategies for invoking subclass methods on generic objects

  - by Brad Patton

  I've run into this issue in a number of places and have solved it a bunch of different ways but looking for other solutions or opinions on how to address. The scenario is when you have a collection of objects all based off of the same superclass but you want to perform certain actions based only on instances of some of the subclasses. One contrived example of this might be an HTML document made up of elements. You could have a superclass named HTMLELement and subclasses of Headings, Paragraphs, Images, Comments, etc. To invoke a common action across all of the objects you declare a virtual method in the superclass and specific implementations in all of the subclasses. So to render the document you could loop all of the different objects in the document and call a common Render() method on each instance. It's the case where again using the same generic objects in the collection I want to perform different actions for instances of specific subclass (or set of subclasses). For example (an remember this is just an example) when iterating over the collection, elements with external links need to be downloaded (e.g. JS, CSS, images) and some might require additional parsing (JS, CSS). What's the best way to handle those special cases. Some of the strategies I've used or seen used include: Virtual methods in the base class. So in the base class you have a virtual LoadExternalContent() method that does nothing and then override it in the specific subclasses that need to implement it. The benefit being that in the calling code there is no object testing you send the same message to each object and let most of them ignore it. Two downsides that I can think of. First it can make the base class very cluttered with methods that have nothing to do with most of the hierarchy. Second it assumes all of the work can be done in the called method and doesn't handle the case where there might be additional context specific actions in the calling code (i.e. you want to do something in the UI and not the model). Have methods on the class to uniquely identify the objects. This could include methods like ClassName() which return a string with the class name or other return values like enums or booleans (IsImage()). The benefit is that the calling code can use if or switch statements to filter objects to perform class specific actions. The downside is that for every new class you need to implement these methods and can look cluttered. Also performance could be less than some of the other options. Use language features to identify objects. This includes reflection and language operators to identify the objects. For example in C# there is the is operator that returns true if the instance matches the specified class. The benefit is no additional code to implement in your object hierarchy. The only downside seems to be the lack of using something like a switch statement and the fact that your calling code is a little more cluttered. Are there other strategies I am missing? Thoughts on best approaches?

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• What are the differences between abstract classes, interfaces, and when to use them

  - by user66662

  Recently I have started to wrap my head around OOP, and I am now to the point where the more I read about the differences between Abstract classes and Interfaces the more confused I become. So far, neither can be instantiated. Interfaces are more or less structural blueprints that determine the skeleton and abstracts are different by being able to partially develop code. I would like to learn more about these through my specific situation. Here is a link to my first question if you would like a little more background information: What is a good design model for my new class? Here are two classes I created: class Ad { $title; $description $price; function get_data($website){ } function validate_price(){ } } class calendar_event { $title; $description $start_date; function get_data($website){ //guts } function validate_dates(){ //guts } } So, as you can see these classes are almost identical. Not shown here, but there are other functions, like get_zip(), save_to_database() that are common across my classes. I have also added other classes Cars and Pets which have all the common methods and of course properties specific to those objects (mileage, weight, for example). Now I have violated the DRY principle and I am managing and changing the same code across multiple files. I intend on having more classes like boats, horses, or whatever. So is this where I would use an interface or abstract class? From what I understand about abstract classes I would use a super class as a template with all of the common elements built into the abstract class, and then add only the items specifically needed in future classes. For example: abstract class content { $title; $description function get_data($website){ } function common_function2() { } function common_function3() { } } class calendar_event extends content { $start_date; function validate_dates(){ } } Or would I use an interface and, because these are so similar, create a structure that each of the subclasses are forced to use for integrity reasons, and leave it up to the end developer who fleshes out that class to be responsible for each of the details of even the common functions. my thinking there is that some 'common' functions may need to be tweaked in the future for the needs of their specific class. Despite all that above, if you believe I am misunderstanding the what and why of abstracts and interfaces altogether, by all means let a valid answer to be stop thinking in this direction and suggest the proper way to move forward! Thanks!

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• how to learn Java

  - by Sarang

  This question I am asking because I couldn't find any source which gives complete overview of java development. I just want to know where java technology currently in market & what is preferable for development ! Java always remain top programming language for development point of view. However, java is combo of, j2ee, j2me, jsp, jsf, spring, other frameworks, ui components, jndi, networking tools and various other "J" are there ! However, learning java is definitely dependent on the development requirement, but still, to be a well-experienced java developer, what is the organised way of learning java? What is preferable in current technology ? and what is deprecated, currently ?

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• Automated testing tool development challenges (for embedded software)

  - by Karthi prime

  My boss want to come up with the proposal for the following tool: An IDE: Able to build, compile, debug, via JTAG programming for the micro-controller. A Test Suite, reads the code in the IDE, auto generates the test cases, and it gives the in-target unit testing results(which is done by controlling code execution in the micro-controller via IDE). A no-overhead code coverage tool which interacts with the test suite and IDE. My work is to obtain the high level architecture of this tool, so as to proceed further. My current knowledge: There are tool-chains available from the chip manufacturer for the micro-controllers which can be utilized along with an open-source IDE like Eclipse, and along with an open-source burner, a complete IDE for a micro-controller can be done. Test cases can be auto-generated by reading the source file through the process of parsing, scripting, based on keywords. Test suite must be able to command the IDE to control, through breakpoints, and read the register contents from the microcontroller - This enables the in-target unit testing. An no-overhead code coverage should be done by no-overhead code instrumentation so as to execute those in the resource constraint environment of the micro-controller. I have the following questions: Any advice on the validity of my understanding? What are the challenges I will have during the development? What are the helpful open-source tools regarding this? What is the development time for this software? Thanks

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• Alternatives to Pessimistic Locking in Cluster Applications

  - by amphibient

  I am researching alternatives to database-level pessimistic locking to achieve transaction isolation in a cluster of Java applications going against the same database. Synchronizing concurrent access in the application tier is clearly not a solution in the present configuration because the same database transaction can be invoked from multiple JVMs concurrently. Currently, we are subject to occasional race conditions which, due to the optimistic locking we have in place via Hibernate, cause a StaleObjectStateException exception and data loss. I have a moderately large transaction within the scope of my refactoring project. Let's describe it as updating one top-level table row and then making various related inserts and/or updates to several of its child entities. I would like to insure exclusive access to the top-level table row and all of the children to be affected but I would like to stay away from pessimistic locking at the database level for performance reasons mostly. We use Hibernate for ORM. Does it make sense to start a single (perhaps synchronous) message queue application into which this method could be moved to insure synchronized access as opposed to each cluster node using its own, which is a clear race condition hazard? I am mentioning this approach even though I am not confident in it because both the top-level table row and its children could also be updated from other system calls, not just the mentioned transaction. So I am seeking to design a solution where the top-level table row and its children will all somehow be pseudo-locked (exclusive transaction isolation) but at the application and not the database level. I am open to ideas and suggestions, I understand this is not a very cut and dried challenge.

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• Everything has an Interface [closed]

  - by Shane

  Possible Duplicate: Do I need to use an interface when only one class will ever implement it? I am taking over a project where every single real class is implementing an Interface. The vast majority of these interfaces are implemented by a single class that share a similar name and the exact same methods (ex: MyCar and MyCarImpl). Almost no 2 classes in the project implement more than the interface that shares its name. I know the general recommendation is to code to an interface rather than an implementation, but isn't this taking it a bit too far? The system might be more flexible in that it is easier to add a new class that behaves very much like an existing class. However, it is significantly harder to parse through the code and method changes now require 2 edits instead of 1. Personally, I normally only create interfaces when there is a need for multiple classes to have the same behavior. I subscribe to YAGNI, so I don't create something unless I see a real need for it. Am I doing it all wrong or is this project going way overboard?

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• good literature for teaching object oriented thinking in C [closed]

  - by Dipan Mehta

  Quite often C is the primary platform for the development. And when things are large scale, I have seen partitioning of the system as different objects is quite a natural thing. Some or many of the object orientated analysis and design principles are used here very well. This is not a debate question about whether or not C is a good candidate for object oriented programming or not. This is also NOT a question how to do OO in C. You can refer to this question and there are probably many such citations. As far as I am concerned, I have learned some of this things while working with many open source and commercial projects. (libjpeg, ffmpeg, Gstreamer which is based on GObject). I can probably extend a few references that explains some of these concepts such as - 1. Event Helix article, 2. Linux Mag article 3. one of my answers which links Schreiner's reference. Unfortunately, when we induct younger folks, it seems too hard to make them learn all of it the hard way. Usually, when we say it's C, a general reaction is to throw away all of the "Object thinking". Looking for help extending above references from those who have been in the similar areas of work. Are there any good formal literature that explains how Object thinking can be made to use while you are working in C? I have seen tons of book on general "object oriented paradigms" but they all focus on advanced languages mostly not in C. You see most C books - but most focus only on the syntax and the obfuscated corners of C and that's it. There are hardly ANY good reference, specially books or any systematic (I mean formal) literature on how to apply OO in C. This is very surprising given that so many large scale open source projects use C which are truly using this very well; but we hardly see any good formal literature on this subject.

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• design in agile process

  - by ying

  Recently I had an interview with dev team in a company. The team uses agile + TDD. The code exercise implements a video rental store which generates statement to calc total rental fee for each type of video (new release, children, etc) for a customer. The existing code use object like: Statement to generate statement and calc fee where big switch statement sits to use enum to determine how to calc rental fee customer holds a list of rentals movie base class and derived class for each type of movie (NEW, CHILDREN, ACTION, etc) The code originally doesn't compile as the owner was assumed to be hit by a bus. So here is what I did: outlined the improvement over object model to have better responsibility for each class. use strategy pattern to replace switch statement and weave them in config But the team says it's waste of time because there is no requirement for it and UAT test suite works and is the only guideline goes into architecture decision. The underlying story is just to get pricing feature out and not saying anything about how to do it. So the discussion is focused on why should time be spent on refactor the switch statement. In my understanding, agile methodology doesn't mean zero design upfront and such code smell should be avoided at the beginning. Also any unit/UAT test suite won't detect such code smell, otherwise sonar, findbugs won't exist. Here I want to ask: is there such a thing called agile design in the agile methodology? Just like agile documentation. how to define agile design upfront? how to know enough is enough? In my understanding, ballpark architecture and data contract among components should be defined before/when starting project, not the details. Am I right? anyone can explain what the team is really looking for in this kind of setup? is it design aspect or agile aspect? how to implement minimum viable product concept in the agile process in the real world project? Is it must that you feel embarrassed to be MVP?

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• How do you off load work from the database?

  - by TheLQ

  In at least the web development field, web servers are everywhere but are backed by very few database servers. As web servers get hit with requests they execute large queries on the database, putting the server under heavy load. While web servers are very easy to scale, db servers are much harder (at least from what I know), making them a precious resource. One way I've heard from some answers here to take load off the database is to offload the work to the web server. Easy, until you realize that now you've got a ton of traffic internally as a web server tries to run SELECT TOP 3000 (presumably to crunch the results on its own), which still slows things down. What are other ways to take load off the database?

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• Has test driven development (TDD) actually benefited a real world project?

  - by James

  I am not new to coding. I have been coding (seriously) for over 15 years now. I have always had some testing for my code. However, over the last few months I have been learning test driven design/development (TDD) using Ruby on Rails. So far, I'm not seeing the benefit. I see some benefit to writing tests for some things, but very few. And while I like the idea of writing the test first, I find I spend substantially more time trying to debug my tests to get them to say what I really mean than I do debugging actual code. This is probably because the test code is often substantially more complicated than the code it tests. I hope this is just inexperience with the available tools (RSpec in this case). I must say though, at this point, the level of frustration mixed with the disappointing lack of performance is beyond unacceptable. So far, the only value I'm seeing from TDD is a growing library of RSpec files that serve as templates for other projects/files. Which is not much more useful, maybe less useful, than the actual project code files. In reading the available literature, I notice that TDD seems to be a massive time sink up front, but pays off in the end. I'm just wondering, are there any real world examples? Does this massive frustration ever pay off in the real world? I really hope I did not miss this question somewhere else on here. I searched, but all the questions/answers are several years old at this point. It was a rare occasion when I found a developer who would say anything bad about TDD, which is why I have spent as much time on this as I have. However, I noticed that nobody seems to point to specific real-world examples. I did read one answer that said the guy debugging the code in 2011 would thank you for have a complete unit testing suite (I think that comment was made in 2008). So, I'm just wondering, after all these years, do we finally have any examples showing the payoff is real? Has anybody actually inherited or gone back to code that was designed/developed with TDD and has a complete set of unit tests and actually felt a payoff? Or did you find that you were spending so much time trying to figure out what the test was testing (and why it was important) that you just tossed out the whole mess and dug into the code?

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• Know Thy Operating System?

  - by AdityaGameProgrammer

  As developers how much time, or do you spend time, In learning the hidden features tricks of your operating system ? How important do you feel is this for productivity in day to day programming? tasks. What do you mean when you list knowledge of an OS in your resume? What are your favorite hidden -less known features For example: A common problem of How can i open the cmd window in a specific location a do it yourself solution in say xp and what to do if something breaks Are these something you look into as and when you find the need to do so?

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• Is type safety worth the trade-offs?

  - by Prof Plum

  I began coding in in Python primarily where there is no type safety, then moved to C# and Java where there is. I found that I could work a bit more quickly and with less headaches in Python, but then again, my C# and Java apps are at much higher level of complexity so I have never given Python a true stress test I suppose. The Java and C# camps make it sound like without the type safety in place, most people would be running into all sorts of horrible bugs left an right and it would be more trouble than its worth. This is not a language comparison, so please do not address issues like compiled vs interpreted. Is type safety worth the hit to speed of development and flexibilty? WHY? to the people who wanted an example of the opinion that dynamic typing is faster: "Use a dynamically typed language during development. It gives you faster feedback, turn-around time, and development speed." - http://blog.jayway.com/2010/04/14/static-typing-is-the-root-of-all-evil/

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• Is SOAP Http POST more complicated than I thought

  - by Pete Petersen

  I'm currently writing a bit of code to send some xml data to a web service via HTTP POST. I thought this would be really simple and have written the following example code (C#) Console.WriteLine("Press enter to send data..."); while (Console.ReadLine() != "q") { HttpWebRequest httpWReq = (HttpWebRequest)WebRequest.Create(@"http://localhost:8888/"); Foo fooItem = new Foo { Member1 = "05", Member2 = "74455604", Member3 = "15101051", Member4 = 1, Member5 = "fsf", Member6 = 6.52, }; ASCIIEncoding encoding = new ASCIIEncoding(); string postData = fooItem.ToXml(); byte[] data = encoding.GetBytes(postData); httpWReq.Method = "POST"; httpWReq.ContentType = "application/xml"; httpWReq.ContentLength = data.Length; using (Stream stream = httpWReq.GetRequestStream()) { stream.Write(data, 0, data.Length); } HttpWebResponse response = (HttpWebResponse)httpWReq.GetResponse(); string responseString = new StreamReader(response.GetResponseStream()).ReadToEnd(); Console.WriteLine("Received " + responseString); Console.WriteLine("Press enter to send data..."); } This is all I thought would be necessary, however I have now been given the details for the web service. This included some information which is unfarmiliar to me and I'm unsure whether I need to include it. The information I was sent was <url>http://sometext/soap/rpc</url> <namespace>http://sometext/a.services</namespace> <method>receiveInfo</method> <parm-id>xmldata</parm-id> (Input data) (Actual XML data as string) <parm-id>status</parm-id> (Output data) <userid>user</userid> <password>pass</password> <secure>false</secure> I guess this means I need to include a username and password somehow, but I'm not sure what the namespace or method fields are used for. Could anyone give me a hint? Sorry I've never used webservices before.

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• Layout of mathematical views (iOS)

  - by William Jockusch

  I am trying to figure out the right way to encapsulate graphical information about mathematical objects. It is not simple. For example, a matrix can include square brackets around its entries, or not. Some things carry down to sub-objects -- for example, a matrix might track the font size to be used by its entries. Similarly, the font color and the background color would carry down to the entries. Other things do not carry down. For example, the entries of the matrix do not need to know whether or not the matrix has those square brackets. Based on all of the above, I need to calculate sizes for everything, then frames. All of this can depend on the properties stored above. The size of a matrix depends on the sizes of its entries, and also on whether or not it has those brackets. What I am having a hard time with is not the individual ways to calculate sensible frames for this or that. It is the overall organizational structure of the whole thing. How can I keep track of it all without going crazy. One particular obstacle is worth mentioning -- for reasons I don't want to go into here, I need to calculate the sizes and frames for everything before I instantiate any actual views. So, for example, if I have a Matrix object, I need to calculate its size before I make a MatrixView. If I have an equation, I need to calculate the size of the view for the equation before I create the actual view. So I clearly need separate objects for those calculations. But I can't figure out a sensible class structure for those objects. If I put them all into a single class, I get some advantages because copying then becomes easy. But I also end up with a bloated class that contains info that is irrelevant for some objects -- such as whether or not to include those brackets around the matrix. But if I use a lot of different classes, copying properties becomes a real pain. If it matters, this is all in Objective C, for an iOS environment. Any pointers would be greatly appreciated.

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• Is it a good idea to appoint one of the scrum team member or scrum master as Product Owner?

  - by Sandy

  Lately we had a project, in which client was busy touring. As usual scrum team was formed, management decided to appoint our analyst as Product owner since Client won’t be able to participate actively. Analyst was the one who worked closely with client for requirement analysis and specification drafting. Client doesn’t have the time to review first two releases. Everything went smoothly until, client saw third release; he wasn’t satisfied with some functionalities, and those was introduced by make shift Product Owner (our analyst). We were told to wait till design team finished mock-up of all pages and client checked each one and approved to continue working. Scrum team is there, but no sprints – we finished work almost like classic waterfall method. Is it a good idea to appoint scrum team member or master as product owner? Do we need to follow scrum in the absence of client/product owner participation?

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• Lean/Kanban *Inside* Software (i.e. WIP-Limits, Reducing Queues and Pull as Programming Techniques)

  - by Christoph

  Thinking about Kanban, I realized that the queuing-theory behind the SW-development-methodology obviously also applies to concurrent software. Now I'm looking for whether this kind of thinking is explicitly applied in some area. A simple example: We usually want to limit the number of threads to avoid cache-thrashing (WIP-Limits). In the paper about the disruptor pattern[1], one statement that I found interesting was that producer/consumers are rarely balanced so when using queues, either consumers wait (queues are empty), or producers produce more than is consumed, resulting in either a full capacity-constrained queue or an unconstrained one blowing up and eating away memory. Both, in lean-speak, is waste, and increases lead-time. Does anybody have examples of WIP-Limits, reducing/eliminating queues, pull or single piece flow being applied in programming? http://disruptor.googlecode.com/files/Disruptor-1.0.pdf

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• Bringing in New Architecture During Maintenance on Legacy Systems

  - by Mike L.

  I have been tasked with adding some new features to a legacy ASP.NET MVC2 project. The codebase is a disaster and I want to write these new features with some thought behind the implementation and not just throw these new features into the mess. I would like to introduce things like dependency injection and the orchestrator pattern; just to the code that I am going to write. I don't have enough time to try to refactor the entire system. Is it OK to not be consistent with the rest of the codebase and add new features following different design principles? Should I not introduce new patterns and just get the features implemented? I feel like it might be confusing to the next person to see parts of the system using a design that other parts are not following.

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• Balancing full time work and personal coding projects.

  - by pllee

  I am nearing the end of developing the major pieces of my website that I have been working on in my spare time for the last 3 months. My goal is to get it released by the end of next month and hopefully start making some money on it. Unfortunately the next step will be to write a lot of specific data handling and ui code that I can see becoming very tedious and boring. When I was first started the project I was able to find time for working on it easily, it was interesting and writing the back-end was new. Once I got to the start of writing stuff that I know and do at work (ui), it seemed harder and harder to make myself work on the project, sometimes the last thing I want to do when I get home from work is code again. Anyone in the same situation? Any tips on how to find time and effort for side projects without burning out? Any tips on staying on the right track?

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• When does implementing MVVM not make sense

  - by Kelly Sommers

  I am a big fan of various patterns and enjoy learning new ones all the time however I think with all the evangelism around popular patterns and anti-patterns sometimes this causes blind adoption. I think most things have individual pros and cons and it's important to educate what the cons are and when it doesn't make sense to make a particular choice. The pros are constantly advocated. "It depends" I think applies most times but the industry does a poor job at communicating what it depends ON. Also many patterns surfaced from inheriting values from previous patterns or have derivatives, which each one brings another set of pros and cons to the table. The sooner we are more aware of the trade off's of decisions we make in software architecture the sooner we make better decisions. This is my first challenge to the community. Even if you are a big fan of said pattern, I challenge you to discover the cons and when you shouldn't use it. Define when MVVM (Model-View-ViewModel) may not make sense in a particular piece of software and based on what reasons. MVVM has a set of pros and cons. Let's try to define them. GO! :)

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• Why isn't LISP more widespread?

  - by Andrea

  I am starting to learn Scheme by the SICP videos, and I would like to move to Common Lisp next. The language seems very interesting, and most of the people writings books on it advocate that it has unequalled expressive power. CL seems to have a decent standard library. Why is not Lisp more widespread? If it is really that powerful, people should be using it all over, but instead it is nearly impossible to find, say, Lisp job advertisements. I hope it is not just the parenthesis, as they are not a great problem after a little while.

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• Is an event loop just a for/while loop with optimized polling?

  - by Alan

  I'm trying to understand what an event loop is. Often the explanation is that in the event loop, you do something until you're notified that an event occurred. You than handle the event and continue doing what you did before. To map the above definition with an example. I have a server which 'listens' in a event loop, and when a socket connection is detected, the data from it gets read and displayed, after which the server goes to the listening it did before. However, this event happening and us getting notified 'just like that' are to much for me to handle. You can say: "It's not 'just like that' you have to register an event listener". But what's an event listener but a function which for some reason isn't returning. Is it in it's own loop, waiting to be notified when an event happens? Should the event listener also register an event listener? Where does it end? Events are a nice abstraction to work with, however just an abstraction. I believe that in the end, polling is unavoidable. Perhaps we are not doing it in our code, but the lower levels (the programming language implementation or the OS) are doing it for us. It basically comes down to the following pseudo code which is running somewhere low enough so it doesn't result in busy waiting: while(True): do stuff check if event has happened (poll) do other stuff This is my understanding of the whole idea, and i would like to hear if this is correct. I am open in accepting that the whole idea is fundamentally wrong, in which case I would like the correct explanation. Best regards

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• LuaJit FFI and hiding C implementation details

  - by wirrbel

  I would like to extend an application using LuaJit FFI. Having seen http://luajit.org/ext_ffi_tutorial.html this is surprisingly easy when comparing this to the Lua C API. So far so good. However I do not plainly want to wrap C functions but provide a higher level API to users writing scripts for the application. Especially I do not want users to be able to access "primitives", i.e. the ffi.* namespace. Is this possible or will that ffi namespace be available to user's Lua scripts? On the issue of Sandboxing Lua I found http://lua-users.org/wiki/SandBoxes which is not talking about FFI though. Furthermore, the plan I have described above is assuming that the introduction of abstraction layers happens on the lua side of code. Is this an advisable approach or would you rather abstract functionality on the statically compiled code (on the C-side)?

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