k-kak

Basic syntax highlighting for K (the K Framework) in the Kakoune text editor.

NOTE: This is now maintained in the K Editor Support Github repository. Please refer to that repository for the latest version, or for reporting issues or suggesting improvements.

Overview

Syntax highlighting definitions are given in the file k.kak. The file defines different highlighting regions, including a region for K code (the default region), a region for string literals, a comments region, and another region for K cell tags. Regions contain the various highlighers (keywords, builtin operators, attributes ... etc). The definitiion also includes specification for automatic indentation and automatic removal of trailing whitespaces, among other details. If you are interested to learn more, see this post for a gentle introduction to defining kakoune highlighters and the official reference document. k.kak uses the same structure used in other definitions that come bundled with kakoune.

Note: Syntax highlighting in k.kak does not attempt to be anywhere near perfect. It's more of a "looks sensible" kind of highlighting. Having said that, I'd very much welcome suggestions for improvement, so please feel free to raise issues or suggest changes.

Screenshot

This is a fragment from the the language imp (from the K tutorials here) highlighted by k-kak:

Installation

There are generally two options to install k-kak:

Option 1: Copy the file k.kak to your kakoune's directory of syntax highlighting definitions, and kakoune will load it automatically. The exact location of this directory depends on your system and how kakoune was installed. In my case (a Ubuntu machine with kakoune compiled from source), that directory is ~/.local/share/kak/autoload/filetype.

Option 2: If you don't want to mess with your kakoune's installation (or don't have write access priviledges to where kakoune is installed), you may copy k.kak to the current user's kakoune config directory located at ~/.config/kak/autoload. You may create this directory if it doesn't exist, and then copy k.kak there.

Note: If you are creating this directory ~/.config/kak/autoload, kakoune will only load the definitions listed in this new directory, unless the directory contains a symlink to the system-wide autoload directory mentioned at Option 1 above (which in my case is ~/.local/share/kak/autoload). So, here are the steps in detail:

1. create the user-level configuration directory, and change to it:

mkdir ~/.config/kak/autoload
cd ~/.config/kak/autoload

2. Create a symlink inside this directory that points to the system-wide autoload folder. In my case, the command was:

ln -s ~/.local/share/kak/autoload autoload

3. Finally, copy over k.kak from this repo to the current directory. Kakoune will now load all the definitions that come bundled with it, along with our new addition k.kak.

Pro Tip!

Kakoune's markdown syntax highlighting supports highlighting code snippets within code blocks, and this includes external definitions like k.kak. To enable it, the only thing the you need to do is add k to the list of languages supported by the markdown highlighter (assuming you have write access to it), as follows:

1. Locate your system-wide syntax highlighting definitions bundled with kakoune (in my case, it's the directory ~/.local/share/kak/autoload/filetype).

2. Open up the file ~/.local/share/kak/autoload/filetype/markdown.kak for editing.

3. Look for the line defining a variable named languages=.... You will see it's a string of space-delimited list of languages supported. Just add k to this string and save your changes.

Below is screenshot of K definitions being highlighted inside various k code blocks in K's builtin domains.md file markdown file:

Note: automatic removal of trailing whitespace does not seem to work inside markdown code blocks for some reason.

Feedback and Suggestions

Feel free to report problems by raising Github issues, or suggest improvements by making Github pull requests, at the K Editor Support Github repository.