This section is intended for users with programming skills.
Sublime Text can be extended through Python plugins. Plugins build features by reusing existing commands or creating new ones. Plugins are a logical entity, rather than a physical one.
In order to write plugins, you must be able to program in Python. At the time of this writing, Sublime Text used Python 3.
Where to Store Plugins¶
Sublime Text will look for plugins only in these places:
- Installed Packages (only .sublime-package files)
As a consequence, any plugin nested deeper in Packages won’t be loaded.
Keeping plugins directly under Packages is discouraged. Sublime Text sorts packages in a predefined way before loading them, so if you save plugin files directly under Packages you might get confusing results.
Your First Plugin¶
Let’s write a “Hello, World!” plugin for Sublime Text:
- Select Tools | New Plugin... in the menu.
- Save to Packages/User/hello_world.py.
You’ve just written your first plugin! Let’s put it to use:
- Create a new buffer (Ctrl+n).
- Open the Python console (Ctrl+`).
- Type: view.run_command("example") and press enter.
You should see the text “Hello, World!” in the newly created buffer.
Analyzing Your First Plugin¶
The plugin created in the previous section should look roughly like this:
import sublime, sublime_plugin class ExampleCommand(sublime_plugin.TextCommand): def run(self, edit): self.view.insert(edit, 0, "Hello, World!")
Both the sublime and sublime_plugin modules are provided by Sublime Text; they are not part of the Python standard library.
As we mentioned earlier, plugins reuse or create commands. Commands are an essential building block in Sublime Text. They are simply Python classes that can be called in similar ways from different Sublime Text facilities, like the plugin API, menu files, macros, etc.
Sublime Text Commands derive from the *Command classes defined in sublime_plugin (more on this later).
The rest of the code in our example is concerned with particulars of TextCommand or with the API. We’ll discuss those topics in later sections.
Before moving on, though, we’ll look at how we invoked the new command: first we opened the Python console and then we issued a call to view.run_command(). This is a rather inconvenient way of calling commands, but it’s often useful when you’re in the development phase of a plugin. For now, keep in mind that your commands can be accessed through key bindings and by other means, just like other commands.
Conventions for Command Names¶
You may have noticed that our command is named ExampleCommand, but we passed the string example to the API call instead. This is necessary because Sublime Text standardizes command names by stripping the Command suffix and separating PhrasesLikeThis with underscores, like so: phrases_like_this.
New commands should follow the same naming pattern.
Types of Commands¶
You can create the following types of commands:
- Window commands (sublime_plugin.WindowCommand)
- Text commands (sublime_plugin.TextCommand)
When writing plugins, consider your goal and choose the appropriate type of commands.
Window commands operate at the window level. This doesn’t mean that you can’t manipulate views from window commands, but rather that you don’t need views in order for window commands to be available. For instance, the built-in command new_file is defined as a WindowCommand so it works even when no view is open. Requiring a view to exist in that case wouldn’t make sense.
Window command instances have a .window attribute to point to the window instance that created them.
The .run() method of a window command doesn’t require any positional parameter.
Window commands are able to route text commands to their window’s active view.
Text commands operate at the view level, so they require a view to exist in order to be available.
Text command instances have a .view attribute pointing to the view instance that created them.
The .run() method of text commands requires an edit instance as its first positional argument.
Text Commands and the edit Object¶
The edit object groups modifications to the view so that undo and macros work sensibly.
Note: Contrary to older versions, Sublime Text 3 doesn’t allow programmatic control over edit objects. The API is in charge of managing their life cycle. Plugin creators must ensure that all modifying operations occur inside the .run method of new text commands. To call existing commands, you can use view.run_command(<cmd_name>, <args>) or similar API calls.
Responding to Events¶
Any command deriving from EventListener will be able to respond to events.
Another Plugin Example: Feeding the Completions List¶
Let’s create a plugin that fetches data from Google’s Autocomplete service and then feeds it to the Sublime Text completions list. Please note that, as ideas for plugins go, this a very bad one.
import sublime, sublime_plugin from xml.etree import ElementTree as ET from urllib.request import urlopen GOOGLE_AC = r"http://google.com/complete/search?output=toolbar&q=%s" class GoogleAutocomplete(sublime_plugin.EventListener): def on_query_completions(self, view, prefix, locations): elements = ET.parse( urlopen(GOOGLE_AC % prefix) ).getroot().findall("./CompleteSuggestion/suggestion") sugs = [(x.attrib["data"],) * 2 for x in elements] return sugs
Make sure you don’t keep this plugin around after trying it or it will interfere with Sublime Text’s autocompletion.
Learning the API¶
In order to create plugins, you need to get acquainted with the Sublime Text API and the available commands. Documentation on both is scarce at the time of this writing, but you can read existing code and learn from it.
In particular, the $PATH_TO_SUBLIME/Packages/Default.sublime-package contains many examples of undocumented commands and API calls. Note that you will first have to extract its content to a folder if you want to take a look at the code within. As an exercise, you can try creating a build system to do that on demand, and a project file to be able to peek at the sample code easily.