C++14 Variable Templates: what is their purpose? Any usage example?

Question

C++14 will allow the creation of variables that are templated. The usual example is a variable \'pi\' that can be read to get the value of the mathematical constant π for va

Answer 1

I have a use case here.

template constexpr CT MARK = '%';
template<> constexpr wchar_t MARK = L'%';

which are used in a string processing template.`

template  
void ProcessString(const std::basic_string& str)
{
    auto&& markpos = str.find(MARK);
    ...
}