chapter.of: Extending the Store
created: 20140710184959721
modified: 20140715084818289
sub.num: 3
tags: doc new
title: System Tiddlers

The core plug-in introduces a segregation of tiddlers.
The tiddler model is central in the whole TiddlyWiki application and can be used in various roles.
Because of the fact that a TiddlyWiki user works with tiddlers (taking the role of a wiki page) and tiddlers are the building blocks of the whole application (including modules, UI elements, etc.) we need to identify the internal tiddlers.

The core plug-in introduces the concept of system tiddlers. It builds on the convention that application internal tiddler names start with ``$:/``.
Then the core plug-in introduces a set of new functions to the wiki store which are used to retrieve tiddlers like ``getTiddlers(options)`` and ``forEachTiddler(callback, options)``.
These functions work with all tiddlers in the store but the options parameter provides the ability to sort tiddlers by a field-name and exclude tiddlers with a specific tag.
By default it doesn't return system tiddlers. To get a list of all tiddlers including system tiddlers, this must be requested explicitly via the options.
If a function wants to present a list of tiddlers to the user it can use this new functions so that internal application tiddlers wouldn't clutter the resulting list.
These functions are added via the [[wikimethod module type]].