Function parse_long

docopt.cpp:212–282

}

static PatternList parse_long(Tokens& tokens, std::vector<Option>& options)
{
	// long ::= '--' chars [ ( ' ' | '=' ) chars ] ;
	std::string longOpt, equal;
	value val;
	std::tie(longOpt, equal, val) = partition(tokens.pop(), "=");

	assert(starts_with(longOpt, "--"));

	if (equal.empty()) {
		val = value{};
	}

	// detect with options match this long option
	std::vector<Option const*> similar;
	for(auto const& option : options) {
		if (option.longOption()==longOpt)
			similar.push_back(&option);
	}

	// maybe allow similar options that match by prefix
	if (tokens.isParsingArgv() && similar.empty()) {
		for(auto const& option : options) {
			if (option.longOption().empty())
				continue;
			if (starts_with(option.longOption(), longOpt))
				similar.push_back(&option);
		}
	}

	PatternList ret;

	if (similar.size() > 1) { // might be simply specified ambiguously 2+ times?
		std::vector<std::string> prefixes = longOptions(similar.begin(), similar.end());
		std::string error = "'" + longOpt + "' is not a unique prefix: ";
		error.append(join(prefixes.begin(), prefixes.end(), ", "));
		throw Tokens::OptionError(std::move(error));
	} else if (similar.empty()) {
		int argcount = equal.empty() ? 0 : 1;
		options.emplace_back("", longOpt, argcount);

		auto o = std::make_shared<Option>(options.back());
		if (tokens.isParsingArgv()) {
			o->setValue(argcount ? value{val} : value{true});
		}
		ret.push_back(o);
	} else {
		auto o = std::make_shared<Option>(*similar[0]);
		if (o->argCount() == 0) {
			if (val) {
				std::string error = o->longOption() + " must not have an argument";
				throw Tokens::OptionError(std::move(error));
			}
		} else {
			if (!val) {
				auto const& token = tokens.current();
				if (token.empty() || token=="--") {
					std::string error = o->longOption() + " requires an argument";