
	// Find
	{
		Database db;
		db.Add({ 2019, 1, 1 }, "e1");
		db.Add({ 2019, 1, 1 }, "e2");
		db.Add({ 2018, 1, 7 }, "e3");
		db.Add({ 2018, 1, 7 }, "e4");
		std::istringstream is("date == 2018-01-07");
		auto const condition = ParseCondition(is);
		auto predicate = [condition](const Date& date, const std::string& event)
		{