You need divisibleby, a built-in django filter. {% for p in posts %} <div class=”post width1 height2 column {% if forloop.counter0|divisibleby:4 %}first{% endif %}”> <div class=”preview”> </div> <div class=”overlay”> </div> <h2>p.title</h2> </div> {% endfor %}
You should only use extern template to force the compiler to not instantiate a template when you know that it will be instantiated somewhere else. It is used to reduce compile time and object file size. For example: // header.h template<typename T> void ReallyBigFunction() { // Body } // source1.cpp #include “header.h” void something1() { … Read more
This is how you would do it: template<typename Type, typename IDType=typename Type::IDType> class Mappings; template<typename Type, typename IDType> class Mappings { public: … Type valueFor(const IDType& id) { // return value } … }; Note that the default is in the forward declaration and not in the actual definition.
THE SIMPLE ANSWER The standard doesn’t allow floating points as non-type template-arguments, which can be read about in the following section of the C++11 standard; 14.3.2/1 Template non-type arguments [temp.arg.nontype] A template-argument for a non-type, non-template template-parameter shall be one of: for a non-type template-parameter of integral or enumeration type, a converted constant … Read more
If you define a template class that you only want to work for a couple of explicit types. Put the template declaration in the header file just like a normal class. Put the template definition in a source file just like a normal class. Then, at the end of the source file, explicitly instantiate only … Read more
VC++ is non-compliant in this case – explicit specializations have to be at namespace scope. C++03, §14.7.3/2: An explicit specialization shall be declared in the namespace of which the template is a member, or, for member templates, in the namespace of which the enclosing class or enclosing class template is a member. An explicit specialization … Read more
Best I can think of is: template<class T, class… Tail> auto make_array(T head, Tail… tail) -> std::array<T, 1 + sizeof…(Tail)> { std::array<T, 1 + sizeof…(Tail)> a = { head, tail … }; return a; } auto a = make_array(1, 2, 3); However, this requires the compiler to do NRVO, and then also skip the copy … Read more
You must create your template files in the correct location; in the templates subdirectory next to the python module (== the module where you create your Flask app). The error indicates that there is no home.html file in the templates/ directory. Make sure you created that directory in the same directory as your python module, … Read more
The other answers are totally fine: One does not need a special syntax to support generics in Python Python uses duck typing as pointed out by André. However, if you still want a typed variant, there is a built-in solution since Python 3.5. A full list of available type annotations is available in the Python … Read more
It is not irrelevant. And no, not every function template is inline by default. The standard is even explicit about it in Explicit specialization ([temp.expl.spec]) Have the following: a.cc #include “tpl.h” b.cc #include “tpl.h” tpl.h (taken from Explicit Specialization): #ifndef TPL_H #define TPL_H template<class T> void f(T) {} template<class T> inline T g(T) {} template<> … Read more