eve::conditional_option Struct Reference

Option specification for decoration via conditional value and expressions. More...

#include <eve/traits/overload/supports.hpp>

Detailed Description

Defined in Header

#include <eve/module/core.hpp>

eve::conditional_option is an option specification that can be used when defining a eve::callable type to make it supports decoration via bool, eve::logical, any eve::conditional_expr or eve::relative_conditional_expr.

Example

#include <iostream>
#include <type_traits>
#include <eve/traits/overload.hpp>
#include <eve/module/core.hpp>
 
namespace eve
{
  // + callable can add rules for decorator to use on a given callable and a default set of options
  // + eve::conditional_option give the ability to pass a mask as a decoration.
  template<typename Options>
  struct func_t : callable<func_t, Options, conditional_option>
  {
    // Note that decoration doesn't impact signature declaration
    template<eve::integral_value T>
    EVE_FORCEINLINE T  operator()(T v) const { return EVE_DISPATCH_CALL(v); }
    EVE_CALLABLE_OBJECT(func_t, func_);
  };
 
  // Build the callable object from the function object type
  inline constexpr auto func = functor<func_t>;
 
  template<typename Options>
  struct other_func_t : callable<other_func_t, Options, relative_conditional_option>
  {
    // Note that decoration doesn't impact signature declaration
    template<eve::integral_value T>
    EVE_FORCEINLINE T  operator()(T v) const { return EVE_DISPATCH_CALL(v); }
    EVE_CALLABLE_OBJECT(other_func_t, other_func_);
  };
 
  // Build the callable object from the function object type
  inline constexpr auto other_func = functor<other_func_t>;
};
 
namespace eve::detail
{
  // Decorated callable takes a eve::options as first parameter
  auto func_(EVE_REQUIRES(cpu_), eve::callable_options auto const& opts, eve::integral_value auto x)
  {
    // See RABERU documentation to check and access options inside a decorator.
    auto const mask = opts[condition_key];
 
    if constexpr(decltype(mask)::is_complete) return x*x;
    else                                      return eve::mul[mask](10,x);
  }
 
  auto other_func_(EVE_REQUIRES(cpu_), eve::callable_options auto const& opts, eve::integral_value auto x)
  {
    // See RABERU documentation to check and access options inside a decorator.
    auto const mask = opts[condition_key];
 
    if constexpr(decltype(mask)::is_complete) return x/10;
    else                                      return eve::mul[mask](x,x);
  }
}
 
template<typename Func, typename Opt>
inline constexpr bool can_be_decorated_with = requires(Func f, Opt o) { f[o]; };
 
int main()
{
  std::cout << eve::func(8) << "\n";
  std::cout << eve::func[false](8) << "\n";
  std::cout << eve::func(eve::wide<short>{77}) << "\n";
  std::cout << eve::func[eve::keep_between(2,6)](eve::wide<short>{77}) << "\n";
 
  std::cout << eve::other_func(80) << "\n";
  std::cout << eve::other_func(eve::wide<short>{77}) << "\n";
  std::cout << eve::other_func[eve::keep_between(2,6)](eve::wide<short>{77}) << "\n";
 
  std::cout << "Is func[bool] supported: "
            << std::boolalpha << can_be_decorated_with<eve::tag_t<eve::func>, bool>
            << "\n";
 
  std::cout << "Is func[eve::keep_between] supported: "
            << std::boolalpha << can_be_decorated_with<eve::tag_t<eve::func>, eve::keep_between>
            << "\n";
 
  std::cout << "Is other_func[bool] supported: "
            << std::boolalpha << can_be_decorated_with<eve::tag_t<eve::other_func>, bool>
            << "\n";
 
  std::cout << "Is other_func[eve::keep_between] supported: "
            << std::boolalpha << can_be_decorated_with<eve::tag_t<eve::other_func>, eve::keep_between>
            << "\n";
}

Public Member Functions
constexpr auto	default_to (auto const &base) const
	Default settings of eve::conditional is eve::ignore_none.