parse_result.h

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#ifndef OOKII_PARSE_RESULT_H_
#define OOKII_PARSE_RESULT_H_
 
#pragma once
 
#include "localized_string_provider.h"
 
namespace ookii
{
    enum class parse_error
    {
        none,
 
        parsing_cancelled,
 
        invalid_value,
 
        unknown_argument,
 
        missing_value,
 
        duplicate_argument,
 
        too_many_arguments,
 
        missing_required_argument,
 
        combined_short_name_non_switch
    };
 
    template<typename CharType, typename Traits = std::char_traits<CharType>, typename Alloc = std::allocator<CharType>>
    struct [[nodiscard]] parse_result
    {
        using string_type = std::basic_string<CharType, Traits, Alloc>;
        using string_provider_type = basic_localized_string_provider<CharType, Traits, Alloc>;
 
        parse_result(const string_provider_type &string_provider, parse_error error = parse_error::none, string_type error_arg_name = {})
            : string_provider{&string_provider},
              error{error},
              error_arg_name{error_arg_name}
        {
        }
 
        const string_provider_type *string_provider;
 
        parse_error error;
 
        string_type error_arg_name;
 
        operator bool() const noexcept
        {
            return error == parse_error::none;
        }
 
        string_type get_error_message() const
        {
            switch (error)
            {
            case parse_error::none:
            case parse_error::parsing_cancelled:
                return {};
 
            case parse_error::invalid_value:
                return string_provider->invalid_value(error_arg_name);
 
            case parse_error::unknown_argument:
                return string_provider->unknown_argument(error_arg_name);
 
            case parse_error::missing_value:
                return string_provider->missing_value(error_arg_name);
 
            case parse_error::duplicate_argument:
                return string_provider->duplicate_argument(error_arg_name);
 
            case parse_error::too_many_arguments:
                return string_provider->too_many_arguments();
 
            case parse_error::missing_required_argument:
                return string_provider->missing_required_argument(error_arg_name);
 
            case parse_error::combined_short_name_non_switch:
                return string_provider->combined_short_name_non_switch(error_arg_name);
 
            default:
                return string_provider->unknown_error();
            }
        }
    };
}
 
#endif