Validators

The Validators Module. More...

Concepts
concept	sharg::validator
	The concept for option validators passed to add_option/positional_option.

Classes
class	sharg::arithmetic_range_validator< option_value_t >
	A validator that checks whether a number is inside a given range. More...
class	sharg::value_list_validator< option_value_t >
	A validator that checks whether a value is inside a list of valid values. More...
class	sharg::file_validator_base
	An abstract base class for the file and directory validators. More...
class	sharg::input_file_validator
	A validator that checks if a given path is a valid input file. More...
class	sharg::output_file_validator
	A validator that checks if a given path is a valid output file. More...
class	sharg::input_directory_validator
	A validator that checks if a given path is a valid input directory. More...
class	sharg::output_directory_validator
	A validator that checks if a given path is a valid output directory. More...
class	sharg::regex_validator
	A validator that checks if a matches a regular expression pattern. More...

Functions
template<validator validator1_type, validator validator2_type> requires std::common_with<typename std::remove_reference_t<validator1_type>::option_value_type, typename std::remove_reference_t<validator2_type>::option_value_type>
auto	sharg::operator| (validator1_type &&vali1, validator2_type &&vali2)
	Enables the chaining of validators.

Detailed Description

The Validators Module.

Function Documentation

operator|()

template<validator validator1_type, validator validator2_type>
requires std::common_with<typename std::remove_reference_t<validator1_type>::option_value_type, typename std::remove_reference_t<validator2_type>::option_value_type>

auto sharg::operator|	(	validator1_type &&	vali1,
		validator2_type &&	vali2 )

Enables the chaining of validators.

Template Parameters

validator1_type	The type of the fist validator; Must satisfy the sharg::validator and the same option_value_type as the second validator type.
validator2_type	The type of the second validator; Must satisfy the sharg::validator and the same option_value_type as the fist validator type.

Parameters

[in]	vali1	The first validator to chain.
[in]	vali2	The second validator to chain.

Returns

A new validator that tests a value for both vali1 and vali2.

The pipe operator is the AND operation for two validators, which means that a value must pass both validators in order to be accepted by the new validator.

For example you may want a file name that only accepts absolute paths but also must have one out of some given file extensions. For this purpose you can chain a sharg::regex_validator to a sharg::input_file_validator like this:

// SPDX-FileCopyrightText: 2006-2024 Knut Reinert & Freie Universität Berlin
// SPDX-FileCopyrightText: 2016-2024 Knut Reinert & MPI für molekulare Genetik
// SPDX-License-Identifier: CC0-1.0
 
#include <sharg/all.hpp>
 
int main(int argc, char const ** argv)
{
    sharg::parser myparser{"Test", argc, argv}; // initialize
 
    std::string file_name;
 
    sharg::regex_validator absolute_path_validator{"(/[^/]+)+/.*\\.[^/\\.]+$"};
    sharg::input_file_validator my_file_ext_validator{{"sa", "so"}};
 
    myparser.add_option(file_name,
                        sharg::config{.short_id = 'f',
                                      .long_id = "file",
                                      .description = "Give me a file name with an absolute path.",
                                      .validator = absolute_path_validator | my_file_ext_validator});
 
    // an exception will be thrown if the user specifies a file name
    // that is not an absolute path or does not have one of the file extension [sa,so]
    try
    {
        myparser.parse();
    }
    catch (sharg::parser_error const & ext) // the user did something wrong
    {
        std::cerr << "[PARSER ERROR] " << ext.what() << "\n"; // customize your error message
        return -1;
    }
 
    std::cout << "filename given by user passed validation: " << file_name << "\n";
    return 0;
}

You can chain as many validators as you want which will be evaluated one after the other from left to right (first to last).

Remarks

For a complete overview, take a look at Parser

This entity is stable. Since version 1.0.