Plugins

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See also

API Reference
More information on the Python API.

Plugins are Python scripts implementing *Command classes from sublime_plugin.

Where to Store Plugins

Sublime Text 2 will look for plugins in these places:

  • Packages
  • Packages/<pkg_name>

Any plugin nested deeper in Packages won’t be loaded.

All plugins should live inside a folder of their own and not directly under Packages.

Conventions for Command Names

By convention, Sublime Text 2 command class names are suffixed with Command and written as CamelCasedPhrases.

However, Sublime Text 2 transforms the class names from CamelCasedPhrases to snake_cased_phrases. So, ExampleCommand would turn into example and AnotherExampleCommand would turn into another_example.

For class definition names, use CamelCasedPhrasesCommand. To call a command from the API, use the normalized name (snake_cased_phrases).

Types of Commands

  • sublime_plugin.ApplicationCommand
  • sublime_plugin.WindowCommand
  • sublime_plugin.TextCommand
  • sublime_plugin.EventListener

Instances of WindowCommand have a .window attribute pointing to the window instance that created them. Similarly, instances of TextCommand have a .view attribute.

Shared Traits for Commands

All commands must implement a .run() method. All commands can receive an arbitrarily long number of keyword arguments, but they all must be valid JSON types.

How to Call Commands from the API

Use a reference to a View or a Window, or sublime depending on the type of command, and call object.run_command('command_name'). In addition, commands accept a dictionary whose keys are the names of valid parameters for them:

window.run_command("echo", {"Tempus": "Irreparabile", "Fugit": "."})

Command Arguments

All user-provided arguments to commands must be valid JSON types. Only Sublime Text itself can pass other types of arguments to commands (such as edit objects, view instances, etc.).

Text Commands and the edit Object

The two API functions of interest are view.begin_edit(), which takes an optional command name and an optional dictionary of arguments, and view.end_edit(), which finishes the edit.

All actions done within an edit are grouped as a single undo action. Callbacks such as on_modified() and on_selection_modified() are called when the edit is finished.

It’s important to call view.end_edit() after each view.begin_edit(), otherwise the buffer will be left in an inconsistent state. An attempt will be made to fix errors when the edit object gets collected, but often that doesn’t happen when you expect, and will result in a warning printed to the console. In other words, you should always bracket an edit in a try..finally block.

The command name passed to begin_edit() is used for repeat, macro recording, and for describing the action when undoing/redoing it. If you’re making an edit outside of a TextCommand, you should almost never supply a command name.

If you have created an edit object, and call a function that creates another one, that’s fine: the edit is considered finished only when the outermost call to end_edit() runs.

As well as for grouping modifications, you can use edit objects for grouping changes to the selection so that they’re undone in a single step.

Responding to Events

Any subclass of EventListener will be able to respond to events. You cannot make a class derive both from EventListener and from any other type of command.

A Word of Warning about EventListener

Expensive operations in event listeners can cause Sublime Text 2 to become unresponsive, especially in events triggered frequently, like on_modified and on_selection_modified. Be careful of how much work is done in these and don’t implement events you don’t need, even if they just pass.

Python and the Standard Library

Sublime Text ships with a trimmed down standard library. The Tkinter, multiprocessing and sqlite3 modules are among the missing ones.

Automatic Plugin Reload

Sublime Text will reload top-level Python modules from packages as they change (perhaps because you are editing a .py file). By contrast, Python subpackages won’t be reloaded automatically, and this can lead to confusion while you’re developing plugins. Generally speaking, it’s best to restart Sublime Text after you’ve made changes to plugin files, so all changes can take effect.

Multithreading

Only the .set_timeout() function is safe to call from different threads.