templates

boost::enable_if class template method

I got class with template methods that looks at this: struct undefined {}; template<typename T> struct is_undefined : mpl::false_ {}; template<> struct is_undefined<undefined> : mpl::true_ {}; template<class C> struct foo { template<class F, class V> typename boost::disable_if<is_undefined<C> >::type apply...

Porting Django's templates engine to C

Hi folks, I recently wrote a simple and tiny embedded HTTP server for my C++ app (QT) and I played a little bit with Ry's http-parser and loved it. This guy is crazy. So I told to myself: "Hey! Why not port the django template engine to C?" That'd be awesome! I know, it won't be an easy task (not at all, I know) but I'd really love to...

doxygen C++ inline template documentation

hello. Is there some way to document template parameters like this: template< int N, ///< description typename T ///< description > rather than listing each parameter with tparam? please note that function arguments can be documented like this in current doxygen: void function(int a /**< description */); if there is not o...

need a virtual template member workaround

Hello, I need to write a program implementing the visitor design pattern. The problem is that the base visitor class is a template class. This means that BaseVisited::accept() takes a template class as a parameter and since it uses 'this' and i need 'this' to point to the correct runtime instance of the object, it also needs to be virtu...

Templated derived class in CRTP (Curiously Recurring Template Pattern)

Hi, I have a use of the CRTP that doesn't compile with g++ 4.2.1, perhaps because the derived class is itself a template? Does anyone know why this doesn't work or, better yet, how to make it work? Sample code and the compiler error are below. Source: foo.C #include <iostream> using namespace std; template<typename X, typename D> str...

C++ templates error: instantiated from 'void TestClass::testMethod(T, std::map) [with T = SomeClass]

Hello there, I've some problem in my code I cannot deal with: #ifndef TESTCLASS_H_ #define TESTCLASS_H_ #include <map> using namespace std; template <typename T> class TestClass { public: TestClass(){}; virtual ~TestClass(){}; void testMethod(T b,std::map<T,int> m); }; template <typename T> void TestClass<T>::testMethod(T b,st...

entity framework POCO template in a n-tiers design question

HI all I was trying to follow the POCO Template walkthrough . And now I am having problems using it in n-tiers design. By following the article, I put my edmx model, and the template generated context.tt in my DAL project, and moved the generated model.tt entity classes to my Business Logic layer (BLL) project. By doing this, I could...

EntityFramework repository template- how to write GetByID lamba within a template class?

I am trying to write a generic one-size-fits-most repository pattern template class for an Entity Framework-based project I'm currently working on. The (heavily simplified) interface is: internal interface IRepository<T> where T : class { T GetByID(int id); IEnumerable<T> GetAll(); IEnumerable<T> Query(Func<T, bool> filter); } G...

rake test not copying development postgres db with sequences

I am trying to develop a rails application on postgresql using a sequence to increment a field instead of a default ruby approach based on validates_uniqueness_of. This has proved challenging for a number of reasons: 1. This is a migration of an existing table, not a new table or column 2. Using parameter :default => "nextval('seq')" di...

Link error for user defined class type template parameter

Hi, I implemented a Simple STL map in C++. Factored out the comparison as a type as I was instructed to, then implemented the comparison as shown below: template <typename T> int KeyCompare<T>::operator () (T tKey1, T tKey2) { if(tKey1 < tKey2) return -1; else if(tKey1 > tKey2) return 1; else r...

Is a function reference sizeof portable?

Hi Looking for a way to do a portable, safe, elements count for c-style arrays, I found this solution: template <typename T, unsigned N> char (&arrayCountofHelper(T(&)[N]))[N]; #define ARRAY_COUNTOF(arr) (sizeof(arrayCountofHelper(arr))) It seems like arrayCountofHelper is actually a reference to a function, and the macro ARRAY_COUNT...

CSS file pathing problem

Hi there, When designing a HTML template in my favorite editor (TextPad at the moment) I can view my code in a browser by pressing F11 or the appropriate toolbar button. I have my common css rules in a separate file so my HTML contains the code: <link rel="stylesheet" href="commoncss.css" type="text/css"> This works when the .css f...

Which CMS to use?

I need to create a web (or non-web) system where a user can create a template layout with tags and placeholders for elements. They could then add new pages to this template. My system would need to pick up any elements that have changed and create an XML of the tagged content. I was just wondering what would be the best CMS or any other ...

Which CMS to use?

I need to create a web (or non-web) system where a user can create a template layout with tags and placeholders for elements. They could then add new pages to this template. My system would need to pick up any elements that have changed and create an XML of the tagged content. I was just wondering what would be the best CMS or any other ...

How to embed a hgactivity graph in hgweb

I would like to embed an actity graph created by hgactivity inside my hgweb webinterface. What's the best method to do so. Here's a screenshot of a hgactivity graph: It shows the number of commits through time to a Mercurial repository. ...

django blog - post- reply system display replies

I have a mini blog app, and a reply system. I want to list all mini blog entries, and their replies, if there are any. i have in views.py def profile_view(request, id): u = UserProfile.objects.get(pk=id) paginator = New.objects.filter(created_by = request.user) replies = Reply.objects.filter(reply_to = paginator...

How do I compile variadic templates conditionally?

Is there a macro that tells me whether or not my compiler supports variadic templates? #ifdef VARIADIC_TEMPLATES_AVAILABLE template<typename... Args> void coolstuff(Args&&... args); #else ??? #endif If they are not supported, I guess I would simulate them with a bunch of overloads. Any better ideas? Maybe there are preprocessor li...

More elegant way to make a C++ member function change different member variables based on template parameter?

Today, I wrote some code that needed to add elements to different container variables depending on the type of a template parameter. I solved it by writing a friend helper class specialized on its own template parameter which had a member variable of the original class. It saved me a few hundred lines of repeating myself without adding...

variadic constructors

Are variadic constructors supposed to hide the implicitly generated ones, i.e. the default constructor and the copy constructor? struct Foo { template<typename... Args> Foo(Args&&... x) { std::cout << "inside the variadic constructor\n"; } }; int main() { Foo a; Foo b(a); } Somehow I was expecting this to ...

Python template engine

Hello there, Could it be possible if somebody could help me get started in writing a python template engine? I'm new to python and as I learn the language I've managed to write a little MVC framework running in its own light-weight-WSGI-like server. I've managed to write a script that finds and replaces keys for values: (Obviously this...