R, knitr, and source function: How to preserve source file comments for html report

Question

R console: When I call source(\"file_of_functions.R\",echo=TRUE), all source file expressions, including comments, print to console.

Answer 1

test.Rmd

---
output: html_document
---

```{r}
options(prompt = '> ')
```

```{r}
source('./test.r', echo = TRUE)
```

```{r}
source('./test.r', echo = TRUE, keep.source = TRUE)
```

Answer 2

I don't mean to post this as an answer, but I just want to point out the possibility that you can easily insert test.r into a code chunk using

```{r code=readLines('test.r')}
```

Personally I think this is much nicer than using source(), e.g. you don't get the prompts > by default (you can if you want), and the R code will be syntax highlighted. Of course, your comments will be preserved.