Concerning Frame V2, I would like to suggest the frames for HLA to support L2 Frame (the full transaction of each signal lane).
Right now the [AnalyzeFrame](support.saleae.com/extensions/api-documentation#class-saleae-analyzers-highlevelanalyzer) returns a single symbol for Async serial instead of a list of symbols.
Changing the Frame to be a transaction and not a single data point would make protocol decoding much easier and would make contribution to the HLA that much simpler.
I've seen mention of using HLA as inputs of other HLA (in the discuss forum but not in the upvoty section).
So far, the "best" solution was to clone the "Text message" and attached a second decode step for my protocol.
We really want to add support to "layer" HLAs, rather than to add more features to LLAs.
We provide an HLA that will concatenate input frames into longer, transaction length frames, like our "Text Messages" example HLA. However, the output of this can't be passed into another HLA, because we don't support that yet.
I think that would be a much better solution, because it allows the determination of where transactions start and end to be left up to a HLA rather than baked into the low level analyzer.
Would that work well for your use case?
In the meantime, you can modify the text messages example HLA to add extra processing too.