我可以重载使用指针和非构造模板对象的运算符吗? [英] Can I overload an operator taking a pointer and a non-constructed template object?

问题描述

我想写一些这样的代码:

I would like to write some code like this:

some_container | foo<args...>;

具体来说，假设RHS为foo<2>.

For concreteness, let's say the RHS is foo<2>.

棘手的部分是，foo是应该自动实例化的内容. IOW，如果必须显式实例化foo<2>，或者如果必须在其后贴上()或{}，我将失败".

The tricky part is, foo is something that should be automatically instantiated. IOW, I "fail" if foo<2> has to be explicitly instantiated, or if I have to stick () or {} after it.

如果LHS是类类型，我可以通过使foo为返回标签"类型的函数，然后提供operator|的模板重载来实现.但是，这不起作用(有关我当前使用的代码，请参见重载运算符|以获取固定大小的数组?以获取我当前使用的代码) LHS也是指针类型，如果它是C样式的数组，也是这种情况.

If the LHS is a class type, I can accomplish this by making foo a function returning a "tag" type, then providing a templated overload of operator|. However, this doesn't work (see Overload operator| for fixed-size arrays? for the code I am currently using) if the LHS is also a pointer type, as is the case if it is a C-style array.

在C ++ 11中是否有 的方式(即不使用C ++ 14变量模板)来实现这种语法?

Is there any way in C++11 (i.e. without using C++14 variable templates) to achieve this syntax?

该表达式的结果最终需要为:

The result of this expression ultimately needs to be :

bar<decltype(some_container), args...>{some_container}

(例如LHS int[N]和RHS foo<2>的bar<int (&)[N], 2>).

(so e.g. bar<int (&)[N], 2> for LHS int[N] and RHS foo<2>).

推荐答案

否.语法foo<...>只能是类(或别名)模板(无效的表达式)或函数模板(成为函数指针，不能对其进行重载).

No. The syntax foo<...> can only be a class (or alias) template (which is an invalid expression) or function template (which becomes a function pointer, which you can’t overload for).

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