plain.h

#pragma once
 
#include <concepts>
#include <functional>
#include <utility>
 
#include <scl/utility/type_traits/forward_like.h>
 
#define SCL_EXECUTOR_CONSTRUCTOR_FOR_SELF_PROTOTYPE(cv_ref)                \
    constexpr explicit plain(self_type cv_ref other) noexcept(             \
        ::std::is_nothrow_constructible_v<value_type, value_type cv_ref>)  \
        requires(::std::constructible_from<value_type, value_type cv_ref>) \
        : m_value{::std::forward<value_type cv_ref>(other.m_value)}        \
    {}

#define SCL_EXECUTOR_CONSTRUCTOR_FOR_SELF                         \
    SCL_EXECUTOR_CONSTRUCTOR_FOR_SELF_PROTOTYPE(&)                \
    SCL_EXECUTOR_CONSTRUCTOR_FOR_SELF_PROTOTYPE(const &)          \
    SCL_EXECUTOR_CONSTRUCTOR_FOR_SELF_PROTOTYPE(volatile &)       \
    SCL_EXECUTOR_CONSTRUCTOR_FOR_SELF_PROTOTYPE(const volatile &) \
    SCL_EXECUTOR_CONSTRUCTOR_FOR_SELF_PROTOTYPE(&&)               \
    SCL_EXECUTOR_CONSTRUCTOR_FOR_SELF_PROTOTYPE(const &&)         \
    SCL_EXECUTOR_CONSTRUCTOR_FOR_SELF_PROTOTYPE(volatile &&)      \
    SCL_EXECUTOR_CONSTRUCTOR_FOR_SELF_PROTOTYPE(const volatile &&)
 
namespace scl::feature::inplace
{
    // NOLINTBEGIN(cppcoreguidelines-special-member-functions, cppcoreguidelines-missing-std-forward)
    template <typename Value>
    class plain
    {
        using self_type = plain<Value>;
 
    public:
        using value_type = Value;
 
    public:
        template <typename... Args>
        constexpr explicit plain(Args &&... args)
            : m_value{::std::forward<Args>(args)...}
        {}
 
        SCL_EXECUTOR_CONSTRUCTOR_FOR_SELF
 
    public:
        template <typename Self, typename Func, typename... Args>
        static constexpr decltype(auto) execute(Self && self, Func && func, Args &&... args)
            requires(::std::same_as<::std::remove_cvref_t<Self>, self_type> && ::std::invocable<Func, Args && ...>)
        {
            return ::std::invoke(::std::forward<Func>(func), ::std::forward<Args>(args)...);
        }
 
        template <typename Self>
        static constexpr decltype(auto) value(Self && self)
            requires ::std::same_as<::std::remove_cvref_t<Self>, self_type>
        {
            return ::scl::forward_like<Self>(self.m_value);
        }
 
    private:
        value_type m_value;
    };
    // NOLINTEND(cppcoreguidelines-special-member-functions, cppcoreguidelines-missing-std-forward)
} // namespace scl::feature::inplace
 
#undef SCL_EXECUTOR_CONSTRUCTOR_FOR_SELF
#undef SCL_EXECUTOR_CONSTRUCTOR_FOR_SELF_PROTOTYPE