helpers.hpp

Go to the documentation of this file.

// Copyright (c) 2023-2025 Jakub Musiał
// This file is part of the CPP-AP project (https://github.com/SpectraL519/cpp-ap).
// Licensed under the MIT License. See the LICENSE file in the project root for full license information.
 
#pragma once
 
#include "concepts.hpp"
 
#include <utility>
#include <variant>
 
namespace ap::action::util {
 
template <c_value_action_specifier AS, ap::util::c_argument_value_type T>
using callable_type = typename AS::template type<T>;
 
template <ap::util::c_argument_value_type T>
using value_action_variant_type = std::variant<
    callable_type<action_type::observe, T>,
    callable_type<action_type::transform, T>,
    callable_type<action_type::modify, T>>;
 
template <ap::util::c_argument_value_type T>
struct apply_visitor {
    using value_type = T;
 
    void operator()(const callable_type<action_type::observe, value_type>& action) const {
        action(std::as_const(value));
    }
 
    void operator()(const callable_type<action_type::transform, value_type>& action) const {
        value = action(std::as_const(value));
    }
 
    void operator()(const callable_type<action_type::modify, value_type>& action) const {
        action(value);
    }
 
    value_type& value; 
};
 
} // namespace ap::action::util