The concept for option validators passed to add_option/positional_option. More...

#include <seqan3/argument_parser/validators.hpp>

Inheritance diagram for validator:

Related Symbols
(Note that these are not member symbols.)
Requirements for seqan3::validator
You can expect these (meta-)functions on all types that implement seqan3::validator.
using	option_value_type
	The type of value on which the validator is called on.

void	operator() (option_value_type const &cmp) const
	Validates the value 'cmp' and throws a seqan3::validation_error on failure.

std::string	get_help_page_message () const
	Returns a message that can be appended to the (positional) options help page info.

Detailed Description

The concept for option validators passed to add_option/positional_option.

When adding (positional) options to the seqan3::argument_parser you may pass a function object that models seqan3::validator which checks the option value provided by the user for some constraint.

SeqAn provides several common-use-case validators, e.g. the seqan3::arithmetic_range_validator.

// 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 <seqan3/argument_parser/all.hpp>
#include <seqan3/core/debug_stream.hpp>
 
int main(int argc, char const ** argv)
{
    seqan3::argument_parser myparser{"Test", argc, argv}; // initialize
 
    int myint;
    seqan3::value_list_validator my_validator{2, 4, 6, 8, 10};
 
    myparser.add_option(myint, 'i', "integer", "Give me a number.", seqan3::option_spec::standard, my_validator);
 
    // an exception will be thrown if the user specifies an integer
    // that is not one of [2,4,6,8,10] (e.g. "./test_app -i 3")
    try
    {
        myparser.parse();
    }
    catch (seqan3::argument_parser_error const & ext) // the user did something wrong
    {
        std::cerr << "[PARSER ERROR] " << ext.what() << "\n"; // customize your error message
        return -1;
    }
 
    seqan3::debug_stream << "integer given by user passed validation: " << myint << "\n";
    return 0;
}

You can learn more about SeqAn validators in our tutorial.

To implement your own validator please refer to the detailed concept description below.

Concepts and doxygen

The requirements for this concept are given as related functions and type traits. Types that satisfy this concept are shown as "implementing this interface".

Friends And Related Symbol Documentation

◆ get_help_page_message()

std::string get_help_page_message ( ) const

Returns: A string that contains information on the performed validation.

Attention: This is a concept requirement, not an actual function (however types satisfying this concept will provide an implementation).

Remarks: For a complete overview, take a look at Argument Parser

Implemented in seqan3::arithmetic_range_validator< option_value_t >, seqan3::value_list_validator< option_value_t >, seqan3::input_file_validator< file_t >, seqan3::output_file_validator< file_t >, seqan3::input_directory_validator, seqan3::output_directory_validator, and seqan3::regex_validator.

◆ operator()()

void operator() ( option_value_type const & cmp ) const

Template Parameters

option_value_type The type of the value to be validated.

Parameters

[in,out] cmp The value to be validated.

Exceptions

seqan3::validation_error if value 'cmp' does not pass validation.

Attention: This is a concept requirement, not an actual function (however types satisfying this concept will provide an implementation).

◆ option_value_type()

using option_value_type

Attention: This is a concept requirement, not an actual typedef (however types satisfying this concept will provide an implementation).

The documentation for this interface was generated from the following file:

validators.hpp