PWGHF: Expression columns to compute combined PID variables

[AlexBigO]

Hi @vkucera !

In the end I defined a new struct before the main one in the selector, to Spawns the PID tables. I aim at using these tables in prong0_as() command, and I don't know if there is a way to both Spawns and consume a table in a struct (as I understand it, it is not possible), so spawning them a priori in a different struct is the only solution I found for the moment.

I added the columns and tables definitions in CandidateReconstructionTables.h, and put the possibility to compute combined PID variables also for the tiny/non-full versions of the PID tables.

[AlexBigO]

I just noticed I forgot to remove this, I will do it when I push the next commit with the PR comments.

[vkucera]

Hi @AlexBigO , thanks for your work.

Spawning and consuming a table within the same struct is possible with bindExternalIndices, as done with the candidate tables here: https://github.com/AliceO2Group/O2Physics/blob/master/PWGHF/TableProducer/candidateCreator2Prong.cxx#L246

[AlexBigO]

Hi @AlexBigO , thanks for your work.

Spawning and consuming a table within the same struct is possible with bindExternalIndices, as done with the candidate tables here: https://github.com/AliceO2Group/O2Physics/blob/master/PWGHF/TableProducer/candidateCreator2Prong.cxx#L246

Hi @vkucera ! Thanks for the comments. Actually, I tried but could not find the right syntax for what I want to do. When using rowTable -> bindExtrernalIndices(&tracks) (where we have Tracks const& tracks in process), one can then loop over Table via for (const auto& row : *rowTable). However, I don't want to do that here, I would like to access Table via an INDEX_COLUMN with a command line such as .prong0_as<Table>. Would you know how to do it?

[vkucera]

Thanks @AlexBigO , it looks good to me. I just have a curious question on the templated return type. Otherwise am happy with merging unless others have further comments.