@staticmethod
def parse(line):
    """Parse crossing data.

        The format is described in :py:meth:`.format`, this method will
        parse this format for a _single_ row of data.

        Parameters
        ----------
        line : string
            A line to parse.

        Returns
        -------
        out[0] : integer
            The step number.
        out[1] : integer
            The interface number.
        out[2] : integer
            The direction, left (-1) or right (1).

        Note
        ----
        A '1' will be subtracted from the interface in analysis. This is
        just for backward compatibility with the old FORTRAN code.

        """
    linessplit = line.strip().split()
    step, inter = int(linessplit[0]), int(linessplit[1])
    direction = -1 if linessplit[2] == '-' else 1
    return step, inter, direction
