buffer << unit_name[len_.unit()];
buffer << '+' << plus_.value();
buffer << unit_name[plus_.unit()];
buffer << unit_name[len_.unit()];
buffer << '+' << plus_.value();
buffer << unit_name[plus_.unit()];
buffer << unit_name[len_.unit()];
buffer << '-' << minus_.value();
buffer << unit_name[minus_.unit()];
buffer << unit_name[len_.unit()];
buffer << '-' << minus_.value();
buffer << unit_name[minus_.unit()];
buffer << unit_name[len_.unit()];
buffer << "+-" << minus_.value();
buffer << unit_name[minus_.unit()];
buffer << unit_name[len_.unit()];
buffer << "+-" << minus_.value();
buffer << unit_name[minus_.unit()];
buffer << '+' << plus_.value() << unit_name[plus_.unit()];
buffer << '-' << minus_.value() << unit_name[minus_.unit()];
buffer << '+' << plus_.value() << unit_name[plus_.unit()];
buffer << '-' << minus_.value() << unit_name[minus_.unit()];
buffer << " plus " << plus_.value() << unit_name[plus_.unit()];
if (!minus_.zero())
buffer << " minus " << minus_.value() << unit_name[minus_.unit()];
buffer << " plus " << plus_.value() << unit_name[plus_.unit()];
if (!minus_.zero())
buffer << " minus " << minus_.value() << unit_name[minus_.unit()];