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• SQL Query: Using IF statement in defining new field

  - by Tofig Hasanov

  I have a table with many fields and additionally several boolean fields (ex: BField1, BField2, BField3 etc.). I need to make a Select Query, which will select all fields except for boolean ones, and a new virtual field (ex: FirstTrueBool) whose value will equal to the name of the first TRUE Boolean Field. For ex: Say I have BField1 = False, BField2 = True, BField3 = true, BField4=false, in that case SQL Query should set [FirstTrueBool] to "BField2". Is that possible? Thank you in advance. P.S. I use Microsoft Access (MDB) Database and Jet Engine.

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• Partially parse C++ for a domain-specific language

  - by PierreBdR

  I would like to create a domain specific language as an augmented-C++ language. I will need mostly two types of contructs: Top-level constructs for specialized types or declarations In-code constructs, i.e. to add primitives to make functions calls or idiom easier The language will be used for scientific computing purposes, and will ultimately be translated into plain C++. C++ has been chosen as it seems to offer a good compromise between: ease of use, efficiency and availability of a wide range of libraries. A previous attempt using flex and bison failed due to the complexity of the C++ syntax. The existing parser can still fail on some constructs. So we want to start over, but on better bases. Do you know about similar projects? And if you attempted to do so, what tools would you use? What would be the main pitfalls? Would you have recommendations in term of syntax?

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• Vector of objects

  - by Paul

  I've got a abstract class class A { public: virtual void somefunction() = ; }; and some different classes that inherit this class: class Ab { public: void somefunction(); }; etc. I want to make a vector containing some objects of these classes (how many depends on input parameters) so I can access these easily later. However I'm a bit lost on how to do this. My best idea is vector<A> *objectsVector; Ab AbObject; objectsVector.push_back(AbObject); However this gives me a huge amout of errors from various .h files in /usr/include/c++ How should i solve this?

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• Updating variables in XSL

  - by Stroboskop

  Is there any way in XSL to update a global variable? I want to check what elements i already transformed and act accordingly. That would require me to somehow add the names of the elements to some sort of list and update it each time a new element is transformed. But since xsl:variable isn't "variable" in the sense one would expect, i have no way of adding anything to it once it has been defined. I have multiple included data files, so using xsl functions that only know the current set of nodes will not help.

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• Objective-C : Changing "self" value inside self

  - by Oliver

  Hello, I have a category on NSDate, and I want to implement some functions to manipulate the date, like : NSDate *thedate = [NSDate date]; [thedate setToMidnight]; so I have a function in NSDate like : -(void)setToMidnight { some code with calendars and comps self = theNewDate; } This works inside the function, but outside this member function, thedate has not changed. I understand this malfunction because I've been told that self is just a local variable created inside the member function. So, how can I make this work ? Of course, I could have written : thedate = [thedate dateAsMidnightDate] or thedate = [NSDate dateAtMidnightFromDate:thedate] but I feel it has more sense inside the instance class, as I don't want to change the date but just adjust some values of the previously created one. Can you help me to achieve this ?

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• Running Firefox in the Windows service mode

  - by Leonid

  I'm writing a server running as a Windows service that by request invokes Firefox to generate a pdf snapshot of a webpage. I know it is a bad idea to run a GUI program in service mode, but the server nature of my program restricts from running it in the user mode. Running a user-level 'proxy' also is not an option, since there might be no interactive user logged-in on the machine with the server running. In my experiments Firefox successfully produced pdf when the service was running under a user account that was already logged-in. Obviously it didn't work in other cases: for Local System and user accounts that weren't logged-in. Under LocalSystem with 'Allow service to interact with desktop' option enabled I could see the Firefox started that reports that it's unable to find a printer. Since it wouldn't be practical to require an opened user session for the pdf server to run, is there any workaround for this except running the whole thing from a virtual machine?

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• std::out_of_range error?

  - by vette982

  I'm dealing with a file with a linked list of lines with each node looking like this: struct TextLine{ //The actual text string text; //The line number of the document int line_num; //A pointer to the next line TextLine * next; }; and I'm writing a function that adds spaces at the beginning of the lines found in the variable text, by calling functions like linelist_ptr->text.insert(0,1,'\t'); The program compiles, but when I run it I get this error: terminate called after throwing an instance of 'std::out_of_range' what(): basic_string::at Aborted Any ideas?

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• MSV1_0 Subauthentication Package Registration

  - by BigShot

  Hi; I'm trying to register a simple MSV1_0 subauthentication package for MS Windows Server 2003. I created a dll which implements required functions described in MSDN. I copied my dll to system32 folder. After that, I created a registry key Auth255 (I also tried Auth128) with a REG_SZ value ,which specifies my dll name, to this location; HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Lsa\MSV1_0. I expect that it will create a test.txt file for debugging puposes when the dll is called, but it doesn't create the file. How can I make this work? MSDN Link for this topic; http://msdn.microsoft.com/en-us/library/aa374786%28VS.85%29.aspx

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• Bootstrap jquery methods Magento's prototype lib

  - by user1722527

  Wonder if anyone has had this issue. I've integrated Bootstrap nicely into a Magento theme I'm building, all good. That is, until I try using the accordian functions. There seems to be an issue with the code finding the Prototype Libs Methods instead of jQuery's. I've tried the usual fixes, $ - jQuery and no conflict but it only works when I disable the prototype lib - which obviously is not good. Anyone out there come across this and can advise me on a work round? At the moment I'm resigned to using Scriptaculous for the accordian.

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• Rscript does not recognize setGeneric function

  - by Branko K.

  I am trying to convert an R script into something that a client can run in batch mode. My code uses generic functions and one snippet which is near the beginning goes like: setGeneric("testInput", function(inputData, params = list()) standardGeneric("testInput")) I've been using R CMD BATCH and it works fine. However I couldn't find an easy way to make my script print the output on the console, so based on that (and suggestion that Rscript.exe is the "proper" way to run R batch files) I decided to switch to Rscript. However when running the very same .R file with Rscript I get the following: Error: could not find function "setGeneric" Execution halted I know there is probably a trivial reason behind this but I just cannot figure it out. Can someone please point me to where the mistake is? Thanks so much in advance. Cheers!

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• Echo html+php from database

  - by pg-robban

  I am working on a site which deals with a lot of texts in HTML, so recently I learned PHP and moved them into a MySQL database and echo the contents given a specific chapter and section. Now this works relatively fine, the HTML shows up properly. However, in some parts I have included PHP function calls, and these doesn't seem to be evaluated - rather, they get just inserted into the source code (and thus invisible for the page viewer), never doing anything. They did work when they were simple .html files. How can I solve this? For example, a text can look like this: <?php printChapterName(); ?> <p>Some text</p> ... <?php showImage($name, $alt-text); ?> ... This just shows the text on the page. Edit: The functions are echo:ing some HTML.

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• How to check for C++ copy ellision

  - by Steve

  I ran across this article on copy ellision in C++ and I've seen comments about it in the boost library. This is appealing, as I prefer my functions to look like verylargereturntype DoSomething(...) rather than void DoSomething(..., verylargereturntype& retval) So, I have two questions about this Google has virtually no documentation on this at all, how real is this? How can I check that this optimization is actually occuring? I assume it involves looking at the assembly, but lets just say that isn't my strong suit. If anyone can give a very basic example as to what successful ellision looks like, that would be very useful I won't be using copy ellision just to prettify things, but if I can be guaranteed that it works, it sounds pretty useful.

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• Java combine parents of two large inheritance chains

  - by Soylent Green

  I have two parent classes in a huge project, let's say ClassA and ClassB. Each class has many subclasses, which in turn have many subclasses, which in turn have many subclasses, etc. My task is to "marry" these two "families" so that both inherit from a SINGLE parent. I need to essentially make ClassA and ClassB one class (parent) to both of their combined subclasses (children). ClassA and ClassB both currently implement Serializable. I am currently trying to make both inheritance chains inherit from ClassA, and then copy all functions and data members from ClassB into ClassA. This is tedious, and I think a terrible solution. What would be the CORRECT way to solve this problem?

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• Is there official API for google-maps driving navigation?

  - by Zigfreid

  I've found that on Google support driving navigation on latest Android. http://www.google.com/mobile/navigation/index.html But, I can't find any kinds of API set to provide those kinds of functions. Is there navigation support API? or isn't it released yet? I can't understand why it's not included on Ginger bread version. They said that Nexus S already support Driving navigation. Do you have any information about this issue? Please let me know. Thanks.

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• XCode iPhone OS Deployment Target Tool

  - by Trah Divad

  Problem I'm currently stuck trying to figure out what "iPhone OS Deployment Target" setting to use. I do not want to write conditional code right now, so I'd like the lowest version that runs my application fine. At first I thought it would be 2.0 as I wasn't using any 3.0 features, but then i realized that AVAudioRecorder is a 3.0 API. I don't want to be manually checking EVERY function I use in the documentation. Question Is there a tool that will check the OS availability of each functions you call in your code to figure out what the Deployment Target should be? That tool could be a good old compiler, but the latest version of the iPhone SDK does not come with the PRE-3.0 SDKs.

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• Is there an equivalent to C++'s "friend class" in Java?

  - by Ricket

  In C++ there is a concept of a "friend", which has access to a class's private variables and functions. So if you have: class Foo { friend class Bar; private: int x; } then any instance of the class Bar can modify any Foo instance's x member, despite it being private, because Bar is a friend of Foo. Now I have a situation in Java where this functionality would come in handy. There are three classes: Database, Modifier, Viewer. The Database is just a collection of variables (like a struct). Modifier should be "friends" with Database; that is, it should be able to read and write its variables directly. But Viewer should only be able to read Database's variables. How is this best implemented? Is there a good way to enforce Viewer's read-only access of Database?

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• OpenGL "out of memory" on glReadPixels()

  - by spurserh

  Hello, I am running into an "out of memory" error from OpenGL on glReadPixels() under low-memory conditions. I am writing a plug-in to a program that has a robust heap mechanism for such situations, but I have no idea whether or how OpenGL could be made to use it for application memory management. The notion that this is even possible came to my attention through this [albeit dated] thread on a similar issue under Mac OS X: http://lists.apple.com/archives/Mac-opengl/2001/Sep/msg00042.html I am using Windows XP, and have seen it on multiple NVidia cards. I am also interested in any work-arounds I might be able to relay to users (the thread mentions "increasing virtual memory"). Thanks, Sean

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• Confused by "let" in Clojure

  - by Tom Dalling

  I just started playing with Clojure, and I wrote a small script to help me understand some of the functions. It begins like this: (def *exprs-to-test* [ "(filter #(< % 3) '(1 2 3 4 3 2 1))" "(remove #(< % 3) '(1 2 3 4 3 2 1))" "(distinct '(1 2 3 4 3 2 1))" ]) Then it goes through *exprs-to-test*, evaluates them all, and prints the output like this: (doseq [exstr *exprs-to-test*] (do (println "===" (first (read-string exstr)) "=========================") (println "Code: " exstr) (println "Eval: " (eval (read-string exstr))) ) ) The above code is all working fine. However, (read-string exstr) is repeated so I tried to use let to eliminate the repetition like so: (doseq [exstr *exprs-to-test*] (let [ex (read-string exstr)] ( (do (println "===" (first ex) "=========================") (println "Code: " exstr) (println "Eval: " (eval ex)) ) )) ) But this works once for the first item in *exprs-to-test*, then crashes with a NullPointerException. Why is the addition of let causing the crash?

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• C++, constructor restrictions

  - by Pie86

  Hi everybaody, I'm studing C++ and I can't understand the meaning of the boldface sentence below: From IBM manual: The following restrictions apply to constructors and destructors: Constructors and destructors do not have return types nor can they return values. References and pointers cannot be used on constructors and destructors because their addresses cannot be taken. Constructors cannot be declared with the keyword virtual. Constructors and destructors cannot be declared static, const, or volatile. Unions cannot contain class objects that have constructors or destructors. Could you please provide me an example? Thank you!

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• Do I have partial view/code behind in Flask?

  - by hbrlovehaku

  I'm migrating from C#.NET to Python/Flask. In .NET I have MasterPage, UserControl, PartialView each has its own code behind. e.g. I can save the check login functions in Login.ascx.cs and render the Login.ascx wherever I'd like to. If logged in, it shows the welcome message, else shows the login form. But in Flask I only found {% include 'login.html' %} which include the static html file. How can I implement this design in Flask?

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• Member variable in C++ class that is always constant for all objects of that class?

  - by user1799323

  I'm constructing a class where I have three member variables that I want to always be the same value NO MATTER WHAT. I have class foo{ public: double var_1, var_2, var_3; double x=1, y=2, z=3; [functions go here] }; that gave me an error since I can't initialize a variable like that. But I want x, y and z to always be 1, 2 and 3 respectively. I tried defining them outside the class but that doesn't work since I want them to be member variables of the class. How do I do this?

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• Return cell reference as result of if statement with vlookups.

  - by EMJ

  I have two sets of data in excel. One contains a set of data which represents the initial step of a process. The other set of data represents the additional steps which take place after the first step is completed. Each of the data records in the "additional step data" has an id in a column. I need to find the identifying codes of the "additional step data" which correspond with the initial step data records. The problem is that I have to match the data in 4 columns between the two data sets and return the id of the "additional step data". I started by doing a combination of an if and vlookup functions, but I got stuck when I tried to figure out how to get the if statement to reference the id of the matching "additional step data". Basically I am trying to avoid having to search by manually filtering between two sets of data and finding corresponding records. Does anyone have any idea about how to do this?

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• portable way to deal with 64/32 bit time_t

  - by MK

  I have some code which is built both on Windows and Linux. Linux at this point is always 32bit but Windows is 32 and 64bit. Windows wants to have time_t be 64 bit and Linux still has it as 32 bit. I'm fine with that, except in some places time_t values are converted to strings. So when time_T is 32 bit it should be done with %d and when it is 64bit with %lld... what is the smart way to do this? Also: any ideas how I may find all places where time_t's are passed to printf-style functions to address this issue?

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• Can I save my app's state at close time in iPhone OS?

  - by Steve

  I have an app that functions much like an ebook. I have a bunch of textual information in various languages that is accessible through a number of drill down methods. When a user wants to get into where they were reading last, they currently have to navigate through the section and chapter menus to get back to where they were. An ideal solution for this would be to setup a bookmark system, which I am considering. But if I remember correctly, when iPhone OS 4 was announced, they seemed to make a big deal of the added ability to save the state of an app. Does that mean that someone using my reader app would be able to just exit right out, do whatever, and then when they came back in, it would be the reading screen just as they left it? I don't know much about how to setup a bookmarking system, I suppose it would be worth investigating, but I would probably want to just hold off for iPhone OS 4 if that is indeed what it will be capable of doing. Any thoughts or insights would be appreciated!!

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• So I dynamically load a jar at runtime how do I use it?

  - by justinhj

  So question 194698 shows how to load a jar file at runtime and you can load individual named classes and get a Class object. Now my problem is I want to be able to cast those Classes to the types they really are, but I can't because I can't use an import since the whole point is to load it at runtime rather than compile time. It seems like the way to go is to use reflection to discover the functions and field names, but that seems brittle since the API in the jar files could change and the code won't break until it is run. Is there a better way?

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