Check if Variant is empty or null in Delphi

IsEmptyOrNull.pas

// uses System, Variants

function IsEmptyOrNull(const Value: Variant): Boolean;
begin
  Result := VarIsClear(Value) or VarIsEmpty(Value) or VarIsNull(Value) or (VarCompareValue(Value, Unassigned) = vrEqual);
  if (not Result) and VarIsStr(Value) then
    Result := Value = '';
end;