Possible to template on types OR non-types?

I use a lot of templates and it's occasionally hard to figure out just what type everything actually is. I wanted to write a utility to give me a nice, pretty string name for every type - typeid() just doesn't cut it. For instance, if I just have a vector<int>, gcc.4.6.4 on my box produces the following with typeid:

St6vectorIiSaIiEE

while I would ideally want

std::vector<
    int,
    std::allocator<
        int
    >
>

I have written something that will work with any type or template on types, but just providing two templates:

template <typename T> struct simple_type_name;
template <template <typename....> class T> struct template_type_name;

Which when specialized on int or std::vector can help me build up the strings I want. I also have a partial specialization of simple_type_name on just any Base<Args...> to walk through all the args and do everything as appropriate. This works totally fine for int and vector<int> and really any arbitrarily complicated template stuff... as long as all the templates are types.

If it helps, my "full template" version looks like this:

template <template <typename...> class Base, typename... Args>
struct simple_type_name<Base<Args...>>
{
    static std::string name(int indent = 0) {
        std::string base = template_type_name<Base>::name(indent);
        std::string args[] = { simple_type_name<Args>::name(indent + 4)... } ;

        // basic string putting together stuff here that is less interesting
    }
};

Question is: how do I make what I have work for, say, std::array<int, 10>? I do not know how to handle the non-type parameters. Is this even possible?

Possible to template on types OR non-types?

2 Answers