Thank you @justyy for your comments! Yeah, it is great to come back! Let me explain a little bit.
- As an R package, the R codes must be put in a folder named 'R'. Otherwise, the package cannot be compiled or accepted by CRAN, as far as I know.
- Yes,
zzz.R
needs a better name. - Yes, a better documentation will be available in the future. I did it too soon.
- I agree. I will write a tutorial later.
Happy New year.