Source an RMD file

source_rmd.R

#' Source the R code from an knitr file, optionally skipping plots
#'
#' @param file the knitr file to source
#' @param skip_plots whether to make plots. If TRUE (default) sets a null graphics device
#'
#' @return This function is called for its side effects
#' @export
source_rmd = function(file, skip_plots = TRUE) {
  temp = tempfile(fileext=".R")
  knitr::purl(file, output=temp)

  if(skip_plots) {
    old_dev = getOption('device')
    options(device = function(...) {
      .Call("R_GD_nullDevice", PACKAGE = "grDevices")
    })
  }
  source(temp)
  if(skip_plots) {
    options(device = old_dev)
  }
}


library(magrittr)
library(stringr)
library(readr)
library(purrr)
library(glue)
library(knitr)

source_rmd_chunks <- function(file, chunk_labels, skip_plots = TRUE){
  
  temp <- tempfile(fileext=".R")
  knitr::purl(file, output = temp)
  
  text <- readr::read_file(temp)

  text <- purrr::map(chunk_labels, ~stringr::str_extract(text, glue::glue("(## ----{var})(.|[:space:])*?(?=(## ----)|$)", var = .x))) %>% 
    stringr::str_c(collapse = "\n")
  
  readr::write_file(text, temp)
  
  if(skip_plots) {
    old_dev = getOption('device')
    options(device = function(...) {
      .Call("R_GD_nullDevice", PACKAGE = "grDevices")
    })
  }
  
  source(temp)
  
  if(skip_plots) {
    options(device = old_dev)
  }
}