I have documentation for functions and datasets in a project folder. In a documentation folder, I have .Rd files for all the datasets. I'd like the user to be able to call a custom help function and launch the .Rd file in the viewer as is done automatically when the file is compiled from the file editor. Is it possible to do this?
I don't quite understand why you want to do this, but it's possible. What you should do is just put your datasets into a package, document them there, and then users get easy access to them.
But if you really want to avoid that for some reason, here's how:
library(magrittr)
library(htmltools)
library(tools)
f <- "some.Rd" # Set a filename for an Rd file here
f %>%
parse_Rd %>%
(function(x) capture.output(Rd2HTML(x))) %>%
HTML %>%
browsable