You have two choices here — the first is the way you did it — simply add the appropriate markup into a template (or a block if you want to be able to override it in templates which extend your first template.) The second way is to use Jinja2’s include function: {% block javascript %} … Read more
This syntax is slightly different. First, because types are easier to work with than packs, a type that holds a pack. The using type=types; just saves me work in the code that generates a types: template<class…>struct types{using type=types;}; Here is the workhorse. It takes a signature, and produces a types<?…> bundle containing the arguments for … Read more
You could refactor or wrap f to return a new X instead of having it passed, since this would play pack expansion into the hand and make the function really concise: template<class T> X fw(T const& t){ X x; f(x, t); return x; } template<class… Args> void h(Args… args){ X xs[] = { fw(args)… }; … Read more
The answer given by Alexey Malistov can be used on MSVC with a minor modification: namespace { template<class T, int discriminator> struct is_complete { static T & getT(); static char (& pass(T))[2]; static char pass(…); static const bool value = sizeof(pass(getT()))==2; }; } #define IS_COMPLETE(X) is_complete<X,__COUNTER__>::value Unfortunately, the __COUNTER__ predefined macro is not part of … Read more
I was hitting the same problem. Enclosing the right part of the case in curly braces fixed the issue for me. This works for me: @user match { case Some(user) => { Welcome, @user.username! } case None => { <a href=”https://stackoverflow.com/questions/9748258/@routes.Application.login”>Login</a> } } Without the braces, it gave an error with the space after the … Read more
The typedef declaration in C++ cannot be a template. However, C++11 added an alternative syntax using the using declaration to allow parametrized type aliases: template <typename T> using Bar = typename Foo<T>::Bar; Now you can use: Bar<int> x; // is a Foo<int>::Bar
The compiler generates the code for the specific types given in the template class instantiation. If you have for instance a template class declaration as template<typename T> class Foo { public: T& bar() { return subject; } private: T subject; }; as soon you have for example the following instantiations Foo<int> fooInt; Foo<double> fooDouble; these … Read more
You won’t need dependency properties because you are inheriting from Button. You already have the IsPressed and IsEnabled properties. In fact, this is all you need: <Button x:Class=”TestWpfApplication.ThreeStateImageButton” xmlns=”http://schemas.microsoft.com/winfx/2006/xaml/presentation” xmlns:x=”http://schemas.microsoft.com/winfx/2006/xaml”> <Button.Template> <ControlTemplate TargetType=”{x:Type Button}”> <Grid> <Image Name=”Normal” Source=”Resources/Normal.png”/> <Image Name=”Pressed” Source=”Resources/Pressed.png” Visibility=”Hidden”/> <Image Name=”Disabled” Source=”Resources/Disabled.png” Visibility=”Hidden”/> </Grid> <ControlTemplate.Triggers> <Trigger Property=”IsPressed” Value=”True”> <Setter TargetName=”Normal” Property=”Visibility” Value=”Hidden”/> … Read more
Personally, the most hideous problem I have seen is the invocation of template functions in dependent context: template <typename T> void foo(T t) { t.bar<3>(); } This looks admittedly simple, but in fact is incorrect. The C++ Standard requires the introduction of the template keyword to disambiguate t.bar < 3 vs a method invocation yielding: … Read more
Just as factorial is not a realistic example of recursion in non-functional languages, neither is it a realistic example of template metaprogramming. It’s just the standard example people reach for when they want to show you recursion. In writing templates for realistic purposes, such as in everyday libraries, often the template has to adapt what … Read more