Issue with optional flag

[mallardtheduck]

See this example:

int main(int argc, char **argv) {
	bool optionSpecified = false;
	std::string optionvalue;

	auto helpCmd = command("help");
	auto cmd1 = command("cmd1");
	auto cmd2 = command("cmd2");
	auto cmd3 = command("cmd3");

	auto optionFlag = (option("-o").set(optionSpecified, true) & value("optionvalue").set(optionvalue));

	auto cli = (helpCmd | cmd1 | ((cmd2 | cmd3), optionFlag));

	if (parse(argc, argv, cli)) {
		tfm::printf("Option: %s Value: %s\n", optionSpecified, optionvalue);
	} else {
		tfm::printf("Parse failed!\n");
		std::cerr << usage_lines(cli, argv[0]) << std::endl;
	}
	return 0;
}

This should accept the "help", "cmd1", "cmd2" or "cmd3" commands, but allow the "-o value" flag to be specified optionally on the "cmd2" or "cmd3" commands. However, while the usage_lines output seems to be correct, the parse fails if "cmd2" or "cmd3" is specified at all, with or without the "-o value" flag.

(tfm::printf is from https://github.com/c42f/tinyformat)

Am I doing something stupid or is this a bug?

[muellan]

You did everything right. It is a bug. I've just discovered where it goes wrong. You can use this workaround, until I have a fix ready:

auto dummy = option("");
auto cli = (helpCmd | (cmd1, dummy) | ((cmd2 | cmd3), optionFlag));

The dummy option doesn't show up in the usage lines.