在概念定义中检查成员函数模板的存在

发布于 2025-02-05 14:20:02 字数 459 浏览 1 评论 0原文

假设我有一个概念概念和一堆类似类型的类型，这些类型提供了一个成员函数模板，如下所示：

class Typical {
  template<Concept T>
  auto something() { return ...; }
};

如何编写概念hassomething测试存在此类存在的概念会员模板功能？请注意，该功能模板没有参数，被设计为obj.something＆lt; t＆gt;（）。我必须测试该函数是否可以使用任何概念来调用。

edit ：我想到的所有方法至少需要提供t的实例。我可以想象如何测试典型::如果 如果某物在其中应该是类模板，而不是用于函数模板，则对某种进行了很好的形式。

原文

Suppose I have a concept Concept and a bunch of similar types that provide a member function template as follows:

class Typical {
  template<Concept T>
  auto something() { return ...; }
};

How do I write a concept HasSomething that tests for the existence of such a member template function? Note that the function template has no arguments and is designed to be called as obj.something<T>(). I have to test whether the function is callable with any Concept.

Edit: all the approaches I can think of require to at least provide an instance of T. I can imagine how to test whether Typical::template something is well-formed if something where supposed to be a class template, but not for a function template.

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