There is a big difference between them. In C++ you don’t have to specify a class or an interface for the generic type. That’s why you can create truly generic functions and classes, with the caveat of a looser typing. template <typename T> T sum(T a, T b) { return a + b; } The … Read more
1. Primary Class Template When you write has_member<A>::value, the compiler looks up the name has_member and finds the primary class template, that is, this declaration: template< class , class = void > struct has_member; (In the OP, that’s written as a definition.) The template argument list <A> is compared to the template parameter list of … Read more
You need to have a ‘static’ folder setup (for css/js files) unless you specifically override it during Flask initialization. I am assuming you did not override it. Your directory structure for css should be like: /app – app_runner.py /services – app.py /templates – mainpage.html /static /styles – mainpage.css Notice that your /styles directory should be … Read more
Put the hack in the template parameters. The enable_if on template parameter approach has at least two advantages over the others: readability: the enable_if use and the return/argument types are not merged together into one messy chunk of typename disambiguators and nested type accesses; even though the clutter of the disambiguator and nested type can … Read more
Your guess is the correct one. The only thing you have to remember is that the member function template definition (in addition to the declaration) should be in the header file, not the cpp, though it does not have to be in the body of the class declaration itself.
Just define it in the header: template <typename T> struct S { static double something_relevant; }; template <typename T> double S<T>::something_relevant = 1.5; Since it is part of a template, as with all templates the compiler will make sure it’s only defined once.
In general, if you are facing a design situation that gives you a choice, use templates. I stressed the word design because I think what you need to focus on is the distinction between the use cases of std::function and templates, which are pretty different. In general, the choice of templates is just an instance … Read more
Another alternative is to nest conditions <ng-container *ngIf=”foo === 1;else second”></ng-container> <ng-template #second> <ng-container *ngIf=”foo === 2;else third”></ng-container> </ng-template> <ng-template #third></ng-template>
You can use {php} tags Method 1 (won’t work in Smarty 3.1 or later): {php} $var = $this->get_template_vars(‘var’); var_dump($var); {/php} Method 2: {$var|@print_r} Method 3: {$var|@var_dump}
SFINAE only works if substitution in argument deduction of a template argument makes the construct ill-formed. There is no such substitution. I thought of that too and tried to use std::is_same< T, int >::value and ! std::is_same< T, int >::value which gives the same result. That’s because when the class template is instantiated (which happens … Read more