Incorporate RMD file in R-package while using non-exported functions

Question

I'm creating an R package which one of its function's output is an HTML report. I want to use an Rmd file to create it, that will be installed within the package.

Following this thread , I understood the usage of inst/rmd/file.Rmd and how to call it ( system.file("rmd", "report.Rmd", package = "thepackage") ).

My package function thepackage::run_report(params, dir) should call the Rmd file, send parameters and eventually export the report to a specified directory.

In the report itself, I'd like to run both exported functions of thepackage AND non-exported functions.

I simplified the code, but it matches the idea.

• Exported function to run the report:

run_report(params, dir = getwd()) {
  input <- system.file("rmd", "report.Rmd", package = "thepackage")

  rmarkdown::render(input = input,
                    params = params,
                    output_file = "report.html",
                    output_dir = dir,
                    clean = TRUE)
}

• report.Rmd. get_data() is also an exported function of thepackage:

---
title: "Comparison Report"
output: html_document
params:
  data: ""
  impute_func: ""

``` {r setup}
    knitr::opts_chunk$set(echo = FALSE, message = FALSE, warning = FALSE, cache = FALSE)
    data <- params$data
    impute_func <- params$impute_func
``` #

``` {r get_data}
    library(thepackage)
    dataset <- get_data(data)
    dataset_ready <- thepackage:::impute_values(data, impute_func)
``` #

``` {r summary}
    summary(dataset_ready)
``` #

I'd like to be able to use both the exported and non-exported functions of thepackage, without having to use the::: command. Overall, I'd like the RMD to behave as any other exported function in the package, which can use non-exported functions from the same package.

If known, what is the best practice for such cases?

Answer 1

Best practice is to use only exported functions. Think about your design carefully if you find that you need to use internal functions: won't users of your package also have the same need?

So there is no standard way to do what you want, but there are lots of possibilities for non-standard ways. Probably the simplest is to have a code block at the beginning of the document that imports each of the internal functions you want, eg

```{r echo = FALSE}
impute_values <- thepackage:::impute_values
```