Code Snippets
Wing Pro's Snippets tool makes it easy to write code that contains commonly reused fragments required by coding standards or commenting and documentation conventions.
Snippets may contain arguments to collect when they are placed into the editor and they may be defined for specific file types or even specific contexts within a file, for example within a class definition or inside a string.
Snippets are invoked by name from the editor's auto-completer or from the key bindings assigned in the Snippets tool. If a snippet contains arguments, they are collected inline in the editor, in a data entry mode.
Although Wing comes with example snippets, in most cases you will want to define your own, to match your coding conventions and preferences.
Snippets Tool
The Snippets tool in the Tools menu is used to create, edit, delete, and manage snippets.
The option drop down in the top right of the Snippets tool (also accessible by right-clicking on the tab area) provides items for adding, removing, and renaming file types into which to organize snippets. The name of the file type is the file extension that Wing should use by default when creating a new file based on a snippet, for example py for Python. The file extension is converted to a mime type internally so that its snippets can also be used in files that use a different valid file extension for the same mime type. The * file type, which is always present, allows defining snippets that can be applied to all file types.
To add, edit, rename, copy, and remove snippets, use the items in the context menu that appears when you right-click on the Snippets tool.
When a snippet is created, it is added to the currently selected file type, and the snippet definition file will be opened into the editor. See Snippet Syntax for details on how to write snippets.
Contexts
Variants of snippets may be defined for different contexts. For example, def may omit or include self depending on whether it is defining a function or a method in a class. The default set of snippets that ship with Wing illustrate this feature with the def and class snippet variants for Python.
The set of valid contexts depends on file type. For Python files the valid context names are module, class, method, function, comment, and string. For HTML and XML, files are divided into content, code (within < and >), comment, and string. Other files only distinguish code, comment, and string. The context all is used for all file types to indicate any context.
The context for a snippet is changed by right-clicking on the item or clicking on the Context column to select a different value.
Key Bindings
The right-click context menu menu on the Snippets tool also allows assigning key bindings to snippets. To enter a key binding, just press the desired binding while focus is in the Key binding field. Bindings can consist of multiple parts, such as Ctrl-H B. Pressing multiple keys will create a key binding sequence, unless too much time elapses between the key presses. To reset the value to blank (no key binding), select all text and press Backspace or Delete.
Key bindings are assigned to the snippet by name and not to a particular snippet file. If multiple like-named snippets exists for different file types or contexts, the snippet that matches the current editor context is chosen.
Execution and Data Entry
The easiest way to invoke snippets is from the auto-completer. Alternatively, they can be invoked by their assigned key bindings (if any), by double clicking on the Snippets tool, or from the right-click context menu in the Snippets tool.
When snippets are invoked, Wing chooses the snippet by name and places the correct variant according to the file type and the context within the current editor. If no context is matched, the snippet for context all is used. The caret position on the editor is used to determine the context, so altering the position of the caret within leading indentation may alter which snippet variant Wing selects.
When placing a snippet into the editor, Wing will insert any default arguments, convert indentation and line endings to match the target file, and place the editor into inline data entry mode to collect additional arguments for the snippet.
In data entry mode, Wing moves between the fields in the snippet when Tab or BackTab are pressed. The position within the snippet's fields will be displayed in the status area at the bottom of the editor window.
While in data entry mode, the Indent and Outdent commands in the Indentation sub-group of Wing's Source menu (and their key equivalents) can be used to increase or decrease the indentation of the whole snippet within the editor. However, the same snippet variant that was used initially will be used regardless of whether changes in indentation also change the context in the editor, for example from method to function.
To exit data entry mode, press Esc (or Ctrl-G in Emacs mode) or move the caret outside of the pasted snippet. To undo the snippet insertion, use Undo in the Edit menu or its key binding.
Scripting Snippets
Wing's extension API exposes the editor's data entry mode and snippet processing capabilities. This can be used to write Python scripts that generate snippets and paste them into the editor for user data entry. This approach allows for more complex logic than Snippet Syntax supports.
For details, see the PasteSnippet and StartDataEntry methods in wingapi.py and refer to Scripting and Extending Wing.
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