// Error - Handle errors by writing a description to STDERR and exiting.
func (sb *SrcBuffer) Error(msg string) {
common.HandleFatal(
common.MakeErrString(msg, sb.curLine.num, sb.curLine.String(), sb.curCol, 1)
);
}
func (piece *SrcPiece) Error(msg string) {
common.HandleFatal(common.MakeErrString(msg, piece.StartLine(), piece.WholeLine(),
piece.StartColumn(), len(piece.Content()) )
);
}