any.cpp

Shows how to use xtd::any_object class.

#include <xtd/any_object>
#include <xtd/console>
#include <xtd/date_time>
 
using namespace xtd;
 
struct foo1 : public object, public icomparable<foo1>, public iequatable<foo1> {
  explicit foo1(int v) : value(v) {}
  int value = 0;
  
  string to_string() const noexcept override {return string::format("{}", value);}
  bool equals(const object& o) const noexcept override {return is<foo1>(o) && equals(static_cast<const foo1&>(o));}
  bool equals(const foo1& f) const noexcept override {return value == f.value;}
  int32 compare_to(const foo1& f) const noexcept override {return value < f.value ? -1 : value > f.value ? 1 : 0;}
};
 
struct foo2 {
  int value = 0;
  
  bool operator ==(const foo2& f) const noexcept {return value == f.value;}
  bool operator <(const foo2& f) const noexcept {return value < f.value;}
  bool operator >(const foo2& f) const noexcept {return value > f.value;}
};
 
template<>
std::string xtd::to_string(const foo2& value, const std::string& fmt, const std::locale& loc) {return xtd::int32_object {value.value}.to_string(fmt, loc);}
 
template<>
struct std::hash<foo2> {
  xtd::size operator()(const foo2& value) const noexcept {return xtd::hash_code::combine(value.value);}
};
 
auto main() -> int {
  auto a = any_object {};
  a = "one";
  console::write_line("a = {} => {} ({})", a, as<string>(a), typeof_(as<string>(a)));
  a = date_time {1971, 1, 5};
  console::write_line("a = {} => {} ({})", a, as<date_time>(a), typeof_(as<date_time>(a)));
  a = 42;
  console::write_line("a = {} => {} ({})", a, as<int32>(a), typeof_(as<int32>(a)));
  a = .42;
  console::write_line("a = {} => {} ({})", a, as<double>(a), typeof_(as<double>(a)));
  a = foo1 {42};
  console::write_line("a = {} => {} ({})", a, as<foo1>(a), typeof_(as<foo1>(a)));
  a = foo2 {42};
  console::write_line("a = {} => {} ({})", a, "NA", typeof_(as<foo2>(a)));
  a = day_of_week::wednesday;
  console::write_line("a = {} => {} ({})", a, as<day_of_week>(a), typeof_(as<day_of_week>(a)));
}
 
// This code produces the following output :
//
// a = one => one (xtd::string)
// a = Tue Jan  5 00:00:00 1971 => Tue Jan  5 00:00:00 1971 (xtd::date_time)
// a = 42 => 42 (int)
// a = 0.42 => 0.42 (double)
// a = 42 => 42 (foo1)
// a = foo2 => NA (foo2)
// a = wednesday => wednesday (xtd::day_of_week)