Several of the DDS ports have the following typedef:
typedef sequence<T> T$Seq;
This leads to an unique sequence type for each DDS interface (MultiWriter,
MultiUpdater, Reader, Getter, MultiListener). This leads to 5 times
typecodes, footprint, but also the sequences are really from a different
type in the programming language. A sequence returned from a Reader, just
can't passed directly into a writer, it are different sequences.
I think we do want to have the same sequence to be used, the one related to
T and this then has to be in the same namespace of T (the topic).
If we for example have
We want to get sequence<GPS> GPSSeq in the global namespace.
Not ::CCM_DDS::GPS_reader::GPSSeq, ::CCM_DDS::GPS_getter::GPSSeq, etc.
I think we should remove the typedef of the interfaces and add it as a
template argument, so that for example we get a reader below.
interface Reader <typename T, typename TSeq>
void read_all (out TSeq instances, out ReadInfoSeq infos)
void read_all_history (out TSeq instances, out ReadInfoSeq infos)
void read_one (inout T an_instance, out ReadInfo info)
void read_one_history (in T an_instance,
out TSeq instances, out ReadInfoSeq infos)
attribute QueryFilter filter
This would mean that the user of the interface/port has to instantiate it
with the basic type and the sequence type, but that seems the only way to
get only one sequence definition used between all the ports, corba, and dds
itself. The seqeunce just also has to be in the same namespace as the
original type T, we just can't do that with a typedef in an interface that
uses the sequence.