Sometimes it is necessary to describe parts of the external format as an in_map, despite the lack of interest in processing the decoded data. That is, when there are more complex types of filler data and this information is to be discarded.
Example - discard_output specification
in_map FillerInMap: external(FillerRecord),
internal(EmptyInternal), discard_output {
automatic;
};
in_map DataInMap: external(DataRecord),
target_internal(DataTarget) {
automatic;
};
decoder TotalDecoder: in_map(FillerInMap), in_map(DataInMap);
This example will produce DataTarget UDRs and discard any filler (assuming that the referred formats have been properly defined).