Raw knitr chunks (inside hook context)

get_raw_chunks.R

# test file
sample_chunk <- "
```{r hello, testing=as.logical(1), another=1 + 1}
1 + 1
```"
file = "sample.Rmd"
writeLines(sample_chunk, con = file)
foo_hook = function(before, options, envir) {
  # only run after the chunk
  if (before) return()
  # note: this returns raw knitr chunks in list format
  # has attribute of "chunk_opts"
  print(knitr::knit_code$get(options$label))
}
knitr::knit_hooks$set(testing = foo_hook)
# option hook to deactivate evaluation if testing chunk option is TRUE 
knitr::opts_hooks$set(testing = function(options) {
  if (isTRUE(options$testing)) options$eval = FALSE
  options
})
outfile <- knitr::knit(file)
file.edit(outfile)
# delete temp md file
on.exit(unlink(outfile))