Say I have an `.Rmd` file like this:

```
The total number of steps per day can also be calculated
using `tapply`.
```{r}
tapply(d$steps, INDEX=d$date, FUN=sum)[1:5]
```
What seems to be different is that, per default, `xtabs`
returns 0 for `NA` values and `tapply` returns `NA`.

```

In my terminal window, this looks like this:

![enter image description here](https://i.stack.imgur.com/Wl9cl.png)

It would be great if somehow I could inform vim that the `R` chunk is actually `R` code which it could highlight just as it does when working in an actual `.R` file.

Is this possible?