This library is not "reentrable", instances of ArgumentParser are not reusable

[KOLANICH]

ArgumentParser::parse_args cannot be used multiple times and it would fail to detect missingness of mandatory positional args. Because of that I have to split tests testing if mandatory positional args work correctly into multiple tests. It is not very convenient.

[skrobinson]

Can you give an example of code that does not work as you expect?

The following code allows me to parse a new set of arguments, adding to already found arguments. Notice in the third parse that program has not forgotten about --config from the second parse.

#include <argparse/argparse.hpp>
#include <iostream>
#include <string>

int main(int argc, const char* argv[]) {
    argparse::ArgumentParser program("test");
    program.add_argument("--config");

    std::string value;
    try {
        program.parse_args({"test"});
        value = program.get("--config");
    } catch (const std::logic_error& err) {
        value = std::string("no argument");
    }
    std::cout << "1) config is '" << value << "'." << std::endl;

    try {
        program.parse_args({"test", "--config", "file.conf"});
        value = program.get("--config");
    } catch (const std::logic_error& err) {
        value = std::string("no argument");
    }
    std::cout << "2) config is '" << value << "'." << std::endl;

    try {
        program.parse_args({"test"});
        value = program.get("--config");
    } catch (const std::logic_error& err) {
        value = std::string("no argument");
    }
    std::cout << "3) config is '" << value << "'." << std::endl;
}

$ ./reuse-parse_args
1) config is 'no argument'.
2) config is 'file.conf'.
3) config is 'file.conf'.