PackageDev is a Sublime Text 2 and 3 package that helps create and edit syntax definitions, snippets, completions files, build systems and other Sublime Text extension files.

The general workflow looks like this:

• run new_* command (new_raw_snippet, new_completions, new_yaml_syntax_def...)
• edit file (with specific snippets, completions, higlighting, build systems...)
• save file

PackageDev commands are typically accessible through the Command Palette (Ctrl+Shift+P) and prefixed by PackageDev:.

1. After installing Package Control, use the Command Palette (Ctrl+Shift+P) to select Install Package and then search for PackageDev.
2. Access commands from Tools | Packages | Package Development or the Command Palette.

In PackageDev, syntax definitions are written in YAML (previously JSON). Sublime Text uses Plist XML files with the .tmLanguage extension, so they need to be converted before use or when you want to modify an already existing syntax definition.

1. Create new template (through Tools | Packages | Package Development) or the Command Palette
2. Select Convert to ... build system from Tools | Build System or leave as Automatic
3. Press Ctrl+B or F7

Other included resources for syntax definition development:

• Syntax highlighting, including Oniguruma regular expressions
• A command to rearrange unsorted (or alphabetically sorted) syntax definitions in YAML. See the command's detailed docstring in file_conversion.py for parameters and more.
• Static and dynamic completions
  • All basic keys like name and captures.
  • Numbers will be turned into capture group elements. This means that typing 4<tab> results in '4': {name: }.
  • Scope names are completed as per TextMate naming conventions, with the last section being the base scope name.
  • Includes are completed as per defined repository keys.

For a good example definition (as to why using YAML is way better than the plain Plist), see the syntax definition for YAML-tmLanguage files and compare it to the converted .tmLanuage equivalent.

You can convert JSON or Plist files to YAML any time (using the Convert to... build system or command palette), but for convenience PackageDev provides a migration command that takes care of all that, and more.

This is highly recommended! Running Convert to YAML and Rearrange Syntax Definition will convert the JSON or Plist syntax definition at hand into YAML and additioally prettify it. To ensure proper markup of the syntax definition, explicitly convert indentation to spaces using the Indentation: Convert to Spaces command before converting.

You can also run the command Rearrange YAML Syntax Definition from the Command Palette manually to sort all lines reasonably, turn strings into their block representation, remove redundant mapping symbols and insert line breaks where they're useful.

The precise steps are thus as follows:

1. Open the *.JSON-tmLanguage or *.tmLanguage file you want to convert.
2. Open the Command Palette and run the Indentation: Convert to Spaces command.
3. Open the Command Palette and run the PackageDev: Convert to YAML and Rearrange Syntax Definition command.

The "Convert to..." build system can interchangably convert JSON, YAML and Plist files. The source format is automatically detected where possible, and you will then be prompted for the target file's format. While this is primarily used for syntax definition, it can be used for any file.

It will also adjust the target file's extension, following a few rules:

• I am json.json is parsed into I am json.plist (or .yaml).
• I am json.JSON-propertyList (or .YAML-propertyList) is parsed into I am json.propertyList.

You can override both, the target format and the extension, by providing an options dict in one of the first three lines of a file. An options dict is indicated by a line comment starting with [PackageDev]. Everything to the end of the line commend (or --> for Plist) will then be treated as a YAML dict.

Currently supported options are:

• target_format, options: plist, yaml and json
• ext, without leading .

Example (YAML): # [PackageDev] target_format: plist, ext: tmLanguage

Note: The JSON parser can handle JavaScript-like // and /* */ comments. For obvious reasons, comments are not preserved.

• Syntax definition for .build-system files.

• Syntax definition for .sublime-keymap files.
• Completions
• Snippets

PackageDev provides a means to edit snippets using snippets. These snippets are called raw snippets. You can use snippets and snippet-like syntax in many files, but if you want to create .sublime-snippet files, you need to convert raw snippets first. This converion is done with a command.

Inside Support you will find a .sublime-keymap file. The key bindings in it are included for reference. If you want them to work, you need to copy the contents over to your personal .sublime-keymap file under Packages/User.

1. Create new raw snippet with included commands (Tools | Packages | Package Development or Command Palette)
2. Edit snippet
3. If needed, convert to .sublime-snippet with included command

You can use raw snippets directly in some files, like .sublime-completions files.

• Syntax definition for .sublime-completions files
• Snippets

You can use raw snippets directly in the contents element of a trigger-based completion.

• Syntax definition for .sublime-settings files
• Snippets

The Snippets folder contains many snippets for all kinds of development mentioned above. These snippets follow memorable rules to make their use easy.

The snippets used more often have short tab triggers like f (field), c (completion), k (key binding), etc. In cases where increasingly complex items of a similar kind might exist (numbered fields, fields with place holders and fields with substitutions in the case of snippets), their tab triggers will consist in a repeated character, like f, ff and fff.

As a rule of thumb, the more complex the snippet, the longer its tab trigger.

Also, i (for item) is often a generic synonym for the most common snippet in a type of file. In such cases, ii and even longer tab triggers might work too, for consistency.

PackageDev previously included sublime_lib, a Python module with utilities for plugin developers. It will be made available as a Package Control dependency soon™.