Setting up R and R Markdown on rkward on Kubuntu

After some time I returned to KDE (in particular, to Kubuntu). I had always liked its style, but unfortunately I always had some problems with stability in previous versions. With version 19.10 – and now the long term stable 20.04 – everything is running smoothly.

Why is Kubuntu good for writing in R Markdown? First, by default it ships the awesome text editor Kate that has nice R Markdown syntax highlighting,¹ spell checking, and syntax highlighting for math equations. Second, KDE offers the powerful R IDE RKward that includes Kate as its code editor. Even better, RKward can be used from any operating system, not just from Kubuntu or other Linux systems. I really encourage everyone to try it out, if just to see an alternative to RStudio once in a while. Moreover, while rkward has been around for a long time, its code base is still being maintained and extended. As it uses Kate as its editor, it also profits freely whenever kate is improved.

As said, Kate should be included by default in the Kubuntu repository. If you are using a different Ubuntu flavor, the following works:

$ sudo apt install kate

RKward can be installed using the standard Ubuntu repository:

$ sudo apt install rkward

Note that this version will be slightly outdated, and more recent versions are available through the launchpad project (see “Inofficial Ubuntu repositories” here).

Building from source is also easier than one may think.² The most recent sources are available from https://invent.kde.org/education/rkward.

Document preview

In the latest versions (v0.7.1 upwards) of RKward, it is possible to activate document preview for R Markdown documents. This is actually a nice advantage over RStudio. It will only preview html documents, but I think for the purpose of editing the writing this should be enough. I even heard that pdf preview is on the maybe-to-do list.

To activate the Preview mode, click the Preview button in the tool bar. If this button does not appear by default, go to Settings -> Configure Toolbars -> mainToolBar <rkward_commandeditor>. In this menu, drag Preview to Current Actions. (Update: In the current version of rkward, this should no longer be necessary.) Now, if you click Preview in the tool bar above the text editor, a html version of your R Markdown document will be rendered whenever you save your file. It looks like this:

Live preview of R Markdown documents in RKward

Setting hard line breaks in Kate

As discussed here, I prefer hard line breaks as opposed to soft breaks. Any text editor I use for writing R Markdown should include functionality for hard line breaks. Fortunately, Kate (and hence, RKward) does. However, we first have to define a custom shortcut for this functionality. This is done via Settings -> Configure Shortcuts -> Apply Word Wrap. I use Alt-Q to insert hard line wraps, as emacs does.

Useful adjustments in rkward settings

Go to Settings -> configure script editor / console

Prevent automcompletion to [[·]] when typing $ by changing the option ‘Operator for access to members of list() and data.frame() objects’
‘Keyboard navigation of completion items: Up/Down cursors’
‘Tab key invokes code completion’
increase time for auto-completion suggestions a little
Disable “Function call tip”; instead, use CTRL-Space to show the arguments of a function, navigate through them and use code complete via TAB

Go to Settings -> Onscreen graphics

Increase the ‘Maximum size of single recorded plot to >9999Kb (otherwise, ’large’ plots will throw a warning which is off-putting and occurs for most ggplots)

Useful Kate features

Focus the Terminal: F4 (goes back as well)
Recognizes git repositories as project, the developers even plan to integrate git better in Kate in the future (see here). This feature is now also available in rkward, which is really awesome for package development.
Set the column limit for hard line breaks: Settings -> Configure Kate -> Editing -> Wrap Words at
You can adjust Kate settings from within RKward as well

Last updated: 2020-11-04

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In general, writing in R Markdown now seems to be much more comfortable than some years back. The atom editor also includes a nice mode for R Markdown documents. However, for now I prefer Kate and rkward.↩
Provided the required build tools are available, which is actually the main problem; in addition to the dependencies listed on the rkward page, I also needed Gettext.↩