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  • Can I add a custom method to Core Data-generated classes?

    - by Andy
    I've got a couple of Core Data-generated class files that I'd like to add custom methods to. I don't need to add any instance variables. How can I do this? I tried adding a category of methods: // ContactMethods.h (my category on Core Data-generated "Contact" class) #import "Contact.h" @interface Contact (ContactMethods) -(NSString*)displayName; @end ... // ContactMethods.m #import "ContactMethods.h" @implementation Contact (ContactMethods) -(NSString*)displayName { return @"Some Name"; // this is test code } @end This doesn't work, though. I get a compiler message that "-NSManagedObject may not respond to 'displayName' " and sure enough, when I run the app, I don't get "Some Name" where I should be seeing it.

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  • Passing a multi-line string as an argument to a script in Windows

    - by Zack Mulgrew
    I have a simple python script like so: import sys lines = sys.argv[1] for line in lines.splitlines(): print line I want to call it from the command line (or a .bat file) but the first argument may (and probably will) be a string with multiple lines in it. How does one do this? Of course, this works: import sys lines = """This is a string It has multiple lines there are three total""" for line in lines.splitlines(): print line But I need to be able to process an argument line-by-line. EDIT: This is probably more of a Windows command-line problem than a Python problem. EDIT 2: Thanks for all of the good suggestions. It doesn't look like it's possible. I can't use another shell because I'm actually trying to invoke the script from another program which seems to use the Windows command-line behind the scenes.

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  • Is it bad practice to select upstream servers based upon the HTTP method?

    - by PartlyCloudy
    I'm wondering if it is bad practice to have a reverse proxy that selects the upstream server depending on the HTTP method used? The background is that I have an abitrary web server that handles POST requests with some logic behind. The same resources also contain static content, that can be retrieved using GET. After some benchmarking I realized that nginx would handle the static content way faster than my abitrary web server doing this. I checked the option to forward incoming requests internally using nginx, which is feasible. But this would lead to the fact that different servers would serve a distinct resource, only depending on issuing a GET or POST, including different header fields.

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  • boost variant static_visitor problem picking correct function

    - by Steve
    I'm sure I'm having a problem with template resolution here, but I'm not sure why I'm having the problem. I have a static visitor I'm passing to boost variant where i've had to do template specialization for certain cases. The case for everything except for MyClass should throw in the static_visitor below. Unfortunately, when the visitor is applied to pull a MyClass out, it selects the most generic case rather than the exact match. I would type each case explicitly, but that will be rather long. So, why is the compiler resolving the most generic case over the exact match, and is there anyway to fix it template<> class CastVisitor<MyClass>:public boost::static_visitor<MyClass> { public: template<typename U> MyClass operator()(const U & i) const { throw std::exception("Unable to cast"); } MyClass operator()(const MyClass& i) { return i; } };

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  • How to explain to a developer that adding extra if - else if conditions is not a good way to "improv

    - by Lilit
    Recently I've bumped into the following C++ code: if (a) { f(); } else if (b) { f(); } else if (c) { f(); } Where a, b and c are all different conditions, and they are not very short. I tried to change the code to: if (a || b || c) { f(); } But the author opposed saying that my change will decrease readability of the code. I had two arguments: 1) You should not increase readability by replacing one branching statement with three (though I really doubt that it's possible to make code more readable by using else if instead of ||). 2) It's not the fastest code, and no compiler will optimize this. But my arguments did not convince him. What would you tell a programmer writing such a code? Do you think complex condition is an excuse for using else if instead of OR?

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  • Operator as and generic classes

    - by abatishchev
    I'm writing .NET On-the-Fly compiler for CLR scripting and want execution method make generic acceptable: object Execute() { return type.InvokeMember(..); } T Execute<T>() { return Execute() as T; /* doesn't work: The type parameter 'T' cannot be used with the 'as' operator because it does not have a class type constraint nor a 'class' constraint */ // also neither typeof(T) not T.GetType(), so on are possible return (T) Execute(); // ok } But I think operator as will be very useful: if result type isn't T method will return null, instead of an exception! Is it possible to do?

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  • How would one call std::forward on all arguments in a variadic function?

    - by Noah Roberts
    I was just writing a generic object factory and using the boost preprocessor meta-library to make a variadic template (using 2010 and it doesn't support them). My function uses rval references and std::forward to do perfect forwarding and it got me thinking...when C++0X comes out and I had a standard compiler I would do this with real variadic templates. How though, would I call std::forward on the arguments? template < typename ... Params void f(Params ... params) // how do I say these are rvalue reference? { y(std::forward(...params)); //? - I doubt this would work. } Only way I can think of would require manual unpacking of ...params and I'm not quite there yet either. Is there a quicker syntax that would work?

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  • Fast comparison of char arrays?

    - by StackedCrooked
    I'm currently working in a codebase where IPv4 addresses are represented as pointers to u_int8. The equality operator is implemented like this: bool Ipv4Address::operator==(const u_int8 * inAddress) const { return (*(u_int32*) this->myBytes == *(u_int32*) inAddress); } This is probably the fasted solution, but it causes the GCC compiler warning: ipv4address.cpp:65: warning: dereferencing type-punned pointer will break strict-aliasing rules How can I rewrite the comparison correctly without breaking strict-aliasing rules and without losing performance points? I have considered using either memcmp or this macro: #define IS_EQUAL(a, b) \ (a[0] == b[0] && a[1] == b[1] && a[2] == b[2] && a[3] == b[3]) I'm thinking that the macro is the fastest solution. What do you recommend?

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  • PHP: form input field names containing square brackets like field[index]

    - by gidireich
    Hi, I've seen lot of code that handle forms, which creates input fields with names containing square brackets. I understand that this is being somehow converted to PHP arrays when a PHP script examines the $_POST variable. My questions about this: What is the mechanism behind? At which point this names that merely contain brackets are converted to arrays? Is this a feature of the HTPP protocol? Of web servers? Of the PHP language? Continuing the previous question, is this a commonly used hack or a normal programming tool? What are (all) the rules of using brackets in input field names? Can multidimensional arrays be created this way? Thanks, Gidi

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  • Resource File Links

    - by EzaBlade
    When you create a Silverlight Business Application you get a Silverlight application and a Web application. In the Web/Resources folder of the Silverlight app there are links to the files in the Resources folder of the Web app. These links are exactly like the files they link to in that they are heirarchical with the Resource.Designer.cs file shown as a code-behind file for the Resource.resx file When I try to link to a Resource file in this way I only get the .resx file unless I link to the .Designer.cs file separately. However in this case the Designer.cs file is then shown as a standard code file and not related to the .resx file. Does anyone know how to do this linking correctly?

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  • how to access child instances in a vector in c++

    - by tsubasa
    I have a parent class and child class (inherited from parent). In the child class, I have a member function named function_blah(); I used vector<parent*> A to store 5 parent instances, 3 child instances. So the total number of elements in the vector is 8. I can easily access to member functions of element A[0] to A[4], which are parent instances. But whenever I try to have access to member functions of element A[5] to A[7], the compiler complains that class parent has no member named 'function_blah' The way I access to elements is using index. e.x A[i] with i = 0..7. Is it correct? if not, how?

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  • Why does C++ linking use virtually no CPU? (updated)

    - by John
    On a native C++ project, linking right now can take a minute or two, yet during this time CPU drops from 100% during compilation to virtually zero. Does this mean linking is primarily a disk activity? If so, is this the main area an SSD would make big changes? But, why aren't all my OBJ files (or as many as possible) kept in RAM after compilation to avoid this? With 4Gb of RAM I should be able to save a lot of disk access and make it CPU-bound again, no? update: so the obvious follow-up is, can VC++ compiler and linker talk together better to streamline things and keep OBJ files in memory, similar to how Delphi does?

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  • How to reference/link another project in grails workspace without using jar files?

    - by Ivan Alagenchev
    I have a Grails website that references a java core application. I have been successful in adding a .jar dependency to that project; however the java project is in the same workspace as my grails project and I would ultimately like to reference that project directly. I don't want to deal with the added step of creating a new jar file every time that there is a modification to the java project, cleaning and updating my dependencies. I added the java project to my grails' project "Java Build Path" and at first everything seemed to work fine, but when I run grailscompile, the compiler fails to resolve all imports that point to the java project. I am using Spring Source Toolsuite as my IDE.

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  • FindControl() method throws ArithmeticException?

    - by Mark Struzinski
    I have a line of C# in my ASP.NET code behind that looks like this: DropDownList ddlStates = (DropDownList)fvAccountSummary.FindControl("ddlStates"); The DropDownList control is explicitly declared in the markup on the page, not dynamically created. It is inside of a FormView control. When my code hits this line, I am getting an ArithmeticException with the message "Value was either too large or too small for an Int32." This code has worked previously, and is in production right now. I fired up VS2008 to make some changes to the site, but before I changed anything, I got this exception from the page. Anyone seen this one before?

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  • Pass an event into a constructor

    - by Vaccano
    I have a class that I want to be able the handle the mouse up event for a grid. I tried to create it with a static method call like this: MyDataBinding.BindObjectsToDataGrid(ListOfObjectsToBind, myGrid.MouseUp); The end goal being that in the method I would assign a delegate to the MouseUp PassedInMouseUp += myMethodThatWillHandleTheMouseUp; Looks good here (to me) but the compiler chokes on the first line. It says that I can only use MouseUp with a += or a -=. Clearly I am going about this the wrong way. How can I get a different class to handle the mouse up with out having to: Pass in the whole grid Expose the method that will be handling the mouse up as a public method. Or, is this just a limitation and I will have to do one of the above?

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  • Browsing to Subversion repository location indicated in Apache conf file

    - by sonrael
    I have Subversion 1.6.6 and Apache 2.2.14 installed and working. I have made the following changes to the Apache httpd.conf file: #Uncommented by me for Subversion installation LoadModule dav_module modules/mod_dav.so LoadModule dav_fs_module modules/mod_dav_fs.so #Added by me for subversion installation LoadModule dav_svn_module modules/mod_dav_svn.so LoadModule authz_svn_module modules/mod_authz_svn.so < Location /svn DAV svn SVNPath C:\Users\RED\Repositories < /Location ...When I navigate to localhost Apache is working properly, but if I try to go to localhost/svn the browser just hangs waiting for a response from the server. What is supposed to happen here? Does it have to do with the fact that I'm behind a wireless router on a dynamic IP address (although I can access localhost no problem so...)? As you can see I'm on windows (Vista)

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  • XAML Multi-Level Binding Source/Path Issue

    - by tpartee
    So I have this issue I've been trying various ways to tackle all day and nothing's catching and working for it. Basically I have a XAML object called ChromeWindow (derived from Window) which has in it's code-behind a DependencyProperty called AppChrome which stores a reference to an associated ApplicationChrome XAML object (derived from UserControl). ApplicationChrome's XAML file has a few x:Name'd objects (a TextBlock and Border for instance) to which I want to bind to from the ChromeWindow's XAML. The root of the ChromeWindow is x:Name'd as 'rootWindow' in the XAML, so I figured one of these bindings would work: {Binding ElementName=rootWindow, Path=AppChrome.CaptionTextBlock.Text, Mode=OneWay} But that complains of a BindingExpression path error such that the property 'CaptionTextBlock' (an x:Name'd TextBlock in AppChrome's XAML) cannot be found on object of type ApplicationChrome So I tried this binding intead: {Binding Source=AppChrome.CaptionTextBlock, Path=Text, Mode=OneWay} And still no luck, this time complaints of a BindingExpression path error again, but this time that it cannot find the 'CaptionTextBlock' property on object of type String I know I'm missing something really simple here, please help! ;D

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  • PHP object help -> unexpected T_OBJECT_OPERATOR

    - by php-b-grader
    Please help me understand: print gettype(new CustomerObject()) prints: "object" (so it is an object) BUT print gettype((new CustomerObject())->get_customer()); prints: unexpected T_OBJECT_OPERATOR If I do it over two lines it works fine $object = new Customer($order->customer_id); print gettype($object); prints: object $customer = $object->get_customer(); print gettype($customer); prints: array It appears that the lines cannot be joined into a single call. Is this correct? and what is the logic behind that?

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  • 'Caching' a large table in ASP.NET

    - by TheNewGuy
    I understand that each page refresh, especially in 'AjaxLand', causes my back-end/code-behind class to be called from scratch... This is a problem because my class (which is a member object in System.Web.UI.Page) contains A LOT of data that it sources from a database. So now every page refresh in AjaxLand is causing me to making large backend DB calls, rather than just to reuse a class object from memory. Any fix for this? Is this where session variables come into play? Are session variables the only option I have to retain an object in memory that is linked to a single-user and a single-session instance?

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  • Whats the difference between a C++ and a Cocoa Project in Xcode?

    - by david
    I need to work with TagLib for my project. I've created a framework (and I tried using it as a lib) but the compiler cannot find #include < strings on compiling (No such file or Directory). I've created a test C++ project and it #includes < strings just fine. I've looked at the project settings and I cannot find a difference between them. But the standard cocoa projects obviously so not have the search path set to include C++ libraries (Or am I completely getting it wrong?). I've searched for a solution but no one else seems to have run into this problem.

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  • qmake library reordering

    - by user1095108
    I put this into a qmake file: QTPLUGIN += component LIBS += -L../lib -lmodule -lcomponent -lnetworking But qmake reorders the libraries behind my back: g++ -m64 -Wl,-O1,--sort-common,--as-needed,-z,relro -o testb .obj/constants.o .obj/main.o .obj/qrc_application.o -L/usr/lib -L../lib -lmodule -lnetworking -lcomponent -lQtGui -lQtNetwork -lQtCore -lpthread Probably because component is a static plugin. But it has a static dependency on the networking library and hence the reordering causes a link error. It is a static dependency and hence is ok in my opinion. How to work around this? I'm using qt 4.8.1.

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  • Are C++ Templates just Macros in disguise?

    - by Roddy
    I've been programming in C++ for a few years, and I've used STL quite a bit and have created my own template classes a few times to see how it's done. Now I'm trying to integrate templates deeper into my OO design, and a nagging thought keeps coming back to me: They're just a macros, really... You could implement (rather UGLY) auto_ptrs using #defines, if you really wanted to. This way of thinking about templates helps me understand how my code will actually work, but I feel that I must be missing the point somehow. Macros are meant evil incarnate, yet "template metaprogramming" is all the rage. So, what ARE the real distinctions? and how can templates avoid the dangers that #define leads you into, like Inscrutable compiler errors in places where you don't expect them? Code bloat? Difficulty in tracing code? Setting Debugger Breakpoints?

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  • Fastest method for SQL Server inserts, updates, selects

    - by Ian
    I use SPs and this isn't an SP vs code-behind "Build your SQL command" question. I'm looking for a high-throughput method for a backend app that handles many small transactions. I use SQLDataReader for most of the returns since forward only works in most cases for me. I've seen it done many ways, and used most of them myself. Methods that define and accept the stored procedure parameters as parameters themselves and build using cmd.Parameters.Add (with or without specifying the DB value type and/or length) Assembling your SP params and their values into an array or hashtable, then passing to a more abstract method that parses the collection and then runs cmd.Parameters.Add Classes that represent tables, initializing the class upon need, setting the public properties that represent the table fields, and calling methods like Save, Load, etc I'm sure there are others I've seen but can't think of at the moment as well. I'm open to all suggestions.

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  • Visual Studio 2010 Compiling C code

    - by Corsen2000
    I have the following code snippet. This is a c file in visual studio 2010. If i try to compile this with the line: int hello = 10; commented out it will compile just fine. If I comment that line in it will not compile. Am I missing something or should I not be using Visual Studio 2010 to compile C code. If this is a Visual Studio problem can anyone recommend a easy to use IDE / Compiler that I can for C. Thank You int* x = (int*) calloc(1, sizeof(int)); *x = 5; //int hello = 10; printf("Hello World! %i", *x); getchar();

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  • How to know record has been updated successfully in php

    - by Lisa Ray
    $sql = "UPDATE...."; if(mysql_query($sql)) { $_SESSION['Trans']="COMMIT"; header("location:result.php"); exit; } else { $_SESSION['Trans']="FAIL"; $_SESSION['errors'] = "Error: Sorry! We are unable to update your Profile, Please contact to PNP HelpDesk."; header("location:result.php"); exit; }//end IF data is getting updated then why compiler is not coming inside IF condition.

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