[Feature request] Support `std::string_view` ?

[Robin SHAMSNEJAD]

Hello,

The add_row method currently does not support inputs of type std::string_view. I think it could be a great idea to add support for it, as tabulate is said to require C++17 in the README.

What do you think ?

[Pranav]

I've added support here #77

#include <tabulate/table.hpp>
using namespace tabulate;
using Row_t = Table::Row_t;

#if __cplusplus >= 201703L
#include <string_view>
using std::string_view;
#else
#include <tabulate/string_view_lite.hpp>
using nonstd::string_view;
#endif

int main() {
  Table table;

  string_view c0 = "string_view";
  const char * c1 = "const char *";
  std::string c2 = "std::string";

  Table c3;
  c3.add_row({"Table", "", ""});
  c3.add_row({c0, c1, c2});
  c3[0].format()
    .border("")
    .corner("");
  
  table.add_row({c0, c1, c2, c3});

  std::cout << table << std::endl;
}

should print:

$ ./samples/string_view_in_row
+-------------+--------------+-------------+----------------------------------------------+
| string_view | const char * | std::string | Table                                        |
|             |              |             | +-------------+--------------+-------------+ |
|             |              |             | | string_view | const char * | std::string | |
|             |              |             | +-------------+--------------+-------------+ |
+-------------+--------------+-------------+----------------------------------------------+

[Robin SHAMSNEJAD]

Thanks !