It appears to show how you build up objects before you pass them to lilypond. You need to create some phrases, then combine them into a score, and call tab(score….).
Personally, I’d rather just write the lilypond code instead of writing R code that will do a conversion to lilypond with whatever restrictions are built into the R data structures found in the tabr package.
I’d suggest you ask for help on R forums; you are the first person I’ve seen on the LilyPond forums asking for help with tabr.
RE: Is anyone using "tabr" ? (tablature oriented package)
Welcome to lilypond. What is your use case? Are you simply wanting to produce guitar tab, or are you wanting to do programmatic/algorithmic composition which outputs to lilypond? If the former, lilypond is fine for TAB as is, and many people use it. As for the algorithmic programming in R using lilypond as a backend, I have a feeling you will need to contact the tabr user community, if they have a mailing list or forum.