comparison_operators.hpp

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#pragma once
#define __XTD_STD_INTERNAL__
#include "internal/__xtd_std_version.hpp"
#undef __XTD_STD_INTERNAL__
 
namespace xtd {
  template<typename type_t, typename comparable_t>
  class comparison_operators {
  public:
    
    friend bool operator <(const type_t& lhs, const type_t& rhs) noexcept {
      auto rhs_ptr = &rhs;
      return dynamic_cast<const type_t*>(rhs_ptr) && lhs.compare_to(static_cast<const type_t&>(rhs)) < 0;
    }
 
    friend bool operator <=(const type_t& lhs, const type_t& rhs) noexcept {
      auto rhs_ptr = &rhs;
      return dynamic_cast<const type_t*>(rhs_ptr) && lhs.compare_to(static_cast<const type_t&>(rhs)) <= 0;
    }
 
    friend bool operator >(const type_t& lhs, const type_t& rhs) noexcept {
      auto rhs_ptr = &rhs;
      return dynamic_cast<const type_t*>(rhs_ptr) && lhs.compare_to(static_cast<const type_t&>(rhs)) > 0;
    }
 
    friend bool operator >=(const type_t& lhs, const type_t& rhs) noexcept {
      auto rhs_ptr = &rhs;
      return dynamic_cast<const type_t*>(rhs_ptr) && lhs.compare_to(static_cast<const type_t&>(rhs)) >= 0;
    }
 
#if defined(__xtd__cpp_lib_three_way_comparison)
    friend std::strong_ordering operator <=>(const type_t& lhs, const type_t& rhs) noexcept {
      auto rhs_ptr = &rhs;
      if (dynamic_cast<const type_t*>(rhs_ptr) && lhs.compare_to(static_cast<const type_t&>(rhs)) < 0) return std::strong_ordering::less;
      if (dynamic_cast<const type_t*>(rhs_ptr) && lhs.compare_to(static_cast<const type_t&>(rhs)) > 0) return std::strong_ordering::greater;
      if (dynamic_cast<const type_t*>(rhs_ptr) && lhs.compare_to(static_cast<const type_t&>(rhs)) == 0) return std::strong_ordering::equivalent;
      return std::strong_ordering::less;
    }
#endif
  private:
    friend comparable_t;
    comparison_operators() = default;
  };
}