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eseilereseiler
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[MISC] Add poison_config
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‎include/sharg/detail/poison_config.hpp‎

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// SPDX-FileCopyrightText: 2006-2024, Knut Reinert & Freie Universität Berlin
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// SPDX-FileCopyrightText: 2016-2024, Knut Reinert & MPI für molekulare Genetik
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// SPDX-License-Identifier: BSD-3-Clause
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/*!\file
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* \author Enrico Seiler <enrico.seiler AT fu-berlin.de>
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* \brief Provides sharg::detail::poison_config.
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*/
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#pragma once
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#include <sharg/config.hpp>
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namespace sharg::detail
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{
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/*!\brief This struct is used to prevent the user from calling sharg::parser::add_option, sharg::parser::add_flag,
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* and sharg::parser::add_positional_option without a sharg::config.
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* \ingroup parser
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* \details
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* This prevents (and produces a legible error message) for calls like:
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* ```
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* parser.add_option(value, {.short_id = 'i', .long_id = "int", .description = "Desc."});
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* ```
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* instead of
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* ```
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* parser.add_option(value, sharg::config{.short_id = 'i', .long_id = "int", .description = "Desc."});
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* ```
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*/
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struct poison_config
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{
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char short_id{'\0'}; //!< Same as sharg::config::short_id.
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std::string long_id{}; //!< Same as sharg::config::long_id.
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std::string description{}; //!< Same as sharg::config::description.
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std::string default_message{}; //!< Same as sharg::config::default_message.
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bool advanced{false}; //!< Same as sharg::config::advanced.
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bool hidden{false}; //!< Same as sharg::config::hidden.
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bool required{false}; //!< Same as sharg::config::required.
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std::any validator{}; //!< Prevents CTAD inside a function call, which would cause a compiler error.
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};
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/*!\brief A validator used for comparing the size of sharg::config and sharg::poison_config.
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* \ingroup parser
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* \details
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* The `sizeof(std::any)` is typically `16`, while `sizeof(sharg::detail::default_validator)` is `1`.
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* `poison_config_size_comp_validator` provides a validator whose size is the same as the size of `std::any`.
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*/
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struct poison_config_size_comp_validator : public detail::default_validator
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{
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std::any validator{}; //!< A member such that the sizes of sharg::config and sharg::poison_config are the same.
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};
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/*!\concept sharg::detail::poison_config_valid
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* \ingroup parser
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* \brief Concept that checks that sharg::poison_config has the same members as sharg::config.
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* \tparam validator_t The validator to use. Defaults to sharg::detail::poison_config_size_comp_validator.
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* \details
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* * Sizes of sharg::config and sharg::detail::poison_config are the same.
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* * sharg::config and sharg::detail::poison_config have the same member types (except validator).
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* * sharg::detail::poison_config can be constructed with designated initializers from sharg::config's members.
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* * sharg::config can be constructed with designated initializers from sharg::detail::poison_config's members.
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* The latter two ensure that the order of the members is the same.
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*/
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template <typename validator_t = poison_config_size_comp_validator>
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concept poison_config_valid =
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(sizeof(poison_config) == sizeof(config<validator_t>))
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&& std::same_as<decltype(poison_config{}.short_id), decltype(config<validator_t>{}.short_id)>
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&& std::same_as<decltype(poison_config{}.long_id), decltype(config<validator_t>{}.long_id)>
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&& std::same_as<decltype(poison_config{}.description), decltype(config<validator_t>{}.description)>
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&& std::same_as<decltype(poison_config{}.default_message), decltype(config<validator_t>{}.default_message)>
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&& std::same_as<decltype(poison_config{}.advanced), decltype(config<validator_t>{}.advanced)>
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&& std::same_as<decltype(poison_config{}.hidden), decltype(config<validator_t>{}.hidden)>
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&& std::same_as<decltype(poison_config{}.required), decltype(config<validator_t>{}.required)>
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&& requires (config<validator_t> cfg, poison_config poison_cfg) {
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{
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poison_config{.short_id = cfg.short_id,
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.long_id = cfg.long_id,
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.description = cfg.description,
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.default_message = cfg.default_message,
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.advanced = cfg.advanced,
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.hidden = cfg.hidden,
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.required = cfg.required,
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.validator = cfg.validator}
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};
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{
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config<validator_t>{.short_id = poison_cfg.short_id,
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.long_id = poison_cfg.long_id,
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.description = poison_cfg.description,
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.default_message = poison_cfg.default_message,
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.advanced = poison_cfg.advanced,
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.hidden = poison_cfg.hidden,
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.required = poison_cfg.required,
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.validator = std::any_cast<validator_t>(poison_cfg.validator)}
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};
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};
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static_assert(poison_config_valid<>, "sharg::detail::poison_config must have the same members as sharg::config!");
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/*!\brief This is a workaround for compilers that do not implement CWG2518 (GCC 11, GCC 12).
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* \ingroup parser
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* \sa https://en.cppreference.com/w/cpp/language/if#Constexpr_if
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* \sa https://cplusplus.github.io/CWG/issues/2518.html
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* \details
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* Before CWG2518, a (discarded) statement couldn't be false in every case, e.g.
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* ```cpp
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* template <typename option_type>
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* void add_option(option_type)
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* {
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* if constexpr (std::is_same_v<option_type, int>)
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* {
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* return;
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* }
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* else
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* {
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* static_assert(false, "Should never happen"); // invalid before CWG2518
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* static_assert(dependent_false_v<option_type>, "Should never happen"); // valid
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* }
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* }
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* ```
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*/
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template <typename>
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inline constexpr bool dependent_false_v = false;
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} // namespace sharg::detail

‎include/sharg/parser.hpp‎

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#include <sharg/detail/format_man.hpp>
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#include <sharg/detail/format_parse.hpp>
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#include <sharg/detail/format_tdl.hpp>
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#include <sharg/detail/poison_config.hpp>
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#include <sharg/detail/version_check.hpp>
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namespace sharg
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format);
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}
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//!\cond DEV
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//!\brief A poison overload that catches calls to add_option without explicitly passing a sharg::config.
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template <typename option_type>
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void add_option(option_type &, detail::poison_config const &)
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{
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static_assert(detail::dependent_false_v<option_type>, "Forgot sharg::config?");
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}
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//!\endcond
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/*!\brief Adds a flag to the sharg::parser.
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*
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* \param[in, out] value The variable which shows if the flag is turned off (default) or on.
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format);
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}
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//!\cond DEV
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//!\brief A poison overload that catches calls to add_flag without explicitly passing a sharg::config.
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template <typename option_type> // Template needed to prevent instantiation of this function if unused.
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void add_flag(option_type &, detail::poison_config const &)
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{
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static_assert(detail::dependent_false_v<option_type>, "Forgot sharg::config?");
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}
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//!\endcond
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/*!\brief Adds a positional option to the sharg::parser.
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*
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* \tparam option_type Must have a formatted input function (stream >> value).
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},
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format);
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}
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//!\cond DEV
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//!\brief A poison overload that catches calls to add_positional_option without explicitly passing a sharg::config.
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template <typename option_type>
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void add_positional_option(option_type &, detail::poison_config const &)
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{
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static_assert(detail::dependent_false_v<option_type>, "Forgot sharg::config?");
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}
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//!\endcond
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//!\}
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/*!\brief Initiates the actual command line parsing.

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