Making symbols available for AsciiDoc syntax in Sublime Text 3

Sublime Text has become my favorite editor on Mac. It is fast, flexible, has tons of useful plugins and I can open any file or directory from the command line using subl. There are many blog post out there describing the strength of Sublime, so today I just wanted to focus on a problem for which I could not find a solution out of the box.

Sublime has become my default editor for Markdown and AsciiDoc. Whereas the symbol navigation via <ctrl+r> works just fine for the Markdown plugin, it is not working for AsciiDoc. This is especially painful when editing long documents where the symbol list gives a fast overview over the file. In fact the missing symbols were nagging me so much, that I decided to embark into a discovery journey into the inner workings of Sublime Text.

In Sublime Text 3 language support (syntax highlighting, snippets, etc) is bundled in a file with the postfix sublime-package. Effectively it is just a zip file which you can expand to view its contents. The main file is .tmLanguage. It contains a whole bunch of regular expressions which capture and name different parts of the syntax of the language in question. To make symbols work you also need a file called *Symbol List.tmPreferences* (the name is not relevant I think), which tells Sublime which of the named syntax parts should be made available via symbols. Exactly this symbol list is missing in the AsciiDoc plugin (http://github.com/SublimeText/AsciiDoc). After looking at *AsciiDoc.tmLanguage*, I thought the following should work:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
   <string>Symbol List</string>

markup.heading.asciidoc is one of the named elements from the tmLanguage file matching a heading line (including the ‘=’ signs). That was good enough for me.

The remaining question was, how to add this symbol list to the existing AsciiDoc sublime-package? Did I have to re-package the zip? Turns out I don’t have to. Zipped packages are installed under

~/Library/Application Support/Sublime Text 3/Installed Packages/\<Package Name\>*

To override a file in any of these zip files or add a new file, create

~/Library/Application Support/Sublime Text 3/Packages/\<Package Name\>

and place your file in there. In case of AsciiDoc this means

~/Library/Application Support/Sublime Text 3/Packages/AsciiDoc/Symbol List.tmPreferences

This is all very well explained here.