Unknown options are silently ignored and mixed with positional arguments #58
Description
When there are options as well as positional arguments, some of which may be optional, there is a problem with unknown options. Consider this repro case:
int foo = 0;
std::string positional;
std::string optional = "default";
auto cli = lyra::cli();
cli |= lyra::opt(foo, "foo")["--foo"];
cli |= lyra::arg(positional, "positional");
cli |= lyra::arg(optional, "optional").optional();
auto result = cli.parse(lyra::args({ argv[0], "--foo", "1", "--bar", "a" }));
if (!result) {
std::cerr << "Error in command line: " << result.errorMessage() << std::endl;
std::cerr << cli << std::endl;
return EXIT_FAILURE;
}
std::cout << "foo = " << foo << std::endl;
std::cout << "positional = " << positional << std::endl;
std::cout << "optional = " << optional << std::endl;which leads to this output:
foo = 1
positional = --bar
optional = a
This is a problem, because --bar as is not reported as unknown/invalid option, but passed to the next positional argument. It is pretty unlikely that the user intended to use --bar as a positional argument -- most likely they made a typo or another mistake and need to read the help page.