An object-oriented package for gravitational tensor calculation, comprising calculation of; - the Levi-Civita connection, the Riemann tensor, the Ricci tensor, the Ricci scalar, the Einstein tensor, the Weyl tensor, and the Kretschmann scalar - the spin connection, and the spin curvature tensor The package treats all the following three cases; - the purely metric case - the purely tetrad case - the mixed case, where both metric and tetrad are present (may, or may not, be independent) The package is able to treat as independent variables the metric, the Levi-Civita connection, the tetrad, and the spin connection