Improving R syntax highlighting in rkward and Kate

Get the original syntax highlighting file

• https://invent.kde.org/frameworks/syntax-highlighting/-/tree/master/data/syntax

Store the custom syntax highlighting file

This is where rkward looks for syntax highlighting definition files:

~/.local/share/katepart5/syntax

This directory may not exist, so it has to be created. Other sources say that

~/.local/share/org.kde.syntax-highlighting/syntax

is also an option for Kate.

• Another option: clone the syntax highlighting git repository and create a symbolic link from the r.xml file (in data -> syntax) to these directories, e.g.:

ln -s ~/git/syntax-highlighting/data/syntax/r.xml ~/.local/share/katepart5/syntax/r.xml
ln -s ~/git/syntax-highlighting/data/syntax/r.xml ~/.local/share/org.kde.syntax-highlighting/syntax/r.xml

Then, you can just stick to working with the r.xml file in the git repository.

Adjust the XML syntax highlighting file

• Documentation of the Kate syntax highlighting xlm declarations
  • https://docs.kde.org/stable5/en/applications/katepart/highlight.html

• In the xml file, change “version” in the language field to a higher number, so this custom file is used by Kate.

• Useful examples for adjusting r.xml:
  • doxygen.xml (for roxygen syntax)

Example 1: Make NA different from NULL and Inf

• Create a new list below the others at the top of the document:

<list name="NA">
  <item>NA</item>
  <item>NA_integer_</item>
  <item>NA_real_</item>
  <item>NA_complex_</item>
  <item>NA_character_</item>
  <item>is.na</item>
</list>

In the context “Common rules”, add:

<keyword attribute="Missing Values" context="#stay" String="NA"/>

In the <itemDatas>, add a new <itemData> for “Missing values”:

<itemData name="Missing Values" defStyleNum="dsDataType" spellChecking="false" bold="1"/>

See the documentation which unique defStyleNums are available.

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Last updated: 2020-11-06

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