How to source R Markdown file like `source('myfile.r')`?

I often have a main R Markdown file or knitr LaTeX file where I source some other R file (e.g., for data processing). However, I was thinking that in some instances it would be beneficial to have these sourced files be their own reproducible documents (e.g., an R Markdown file that not only includes commands for data processing, but also produces a reproducible document that explains the data processing decisions).

Thus, I would like to have a command like source('myfile.rmd') in my main R Markdown file. that would extract and source all the R code inside the R code chunks of myfile.rmd. Of course, this gives rise to an error.

The following command works:

```{r message=FALSE, results='hide'}
knit('myfile.rmd', tangle=TRUE)
source('myfile.R')
```

where results='hide' could be omitted if output was desired. I.e., knitr outputs the R code from myfile.rmd into myfile.R.

However, it doesn't seem perfect:

• it results in the creation of an extra file
• it needs to appear in it's own code chunk if control over display is required.
• It's not as elegant as simple source(...).

Thus my question: Is there a more elegant way of sourcing the R code of an R Markdown file?