plainleaf/website/Object.md

SilverBullet automatically builds and maintains an index of objects extracted from all Markdown Page in your Space. It subsequently allows you to use Space Lua/Lua Integrated Query to query this database in (potentially) useful ways.

By design, the truth remains in the markdown: all data indexed as objects will have a representation in markdown text as well. This index can be flushed at any time and be rebuilt from its source markdown files kept in your space (and you can do so on demand if you like using the Space: Reindex command).

Object representation

Every object has a set of Attribute, some predefined, but you can add any additional custom attributes that you like.

The following attributes are predefined, and you can expect all objects to have them:

• ref: a globally unique identifier, often represented as a pointer to the place (page, position) in your space where the object is defined. For instance, a page object will use the page name as its ref attribute, and a task will use page@pos (where pos is the location the task appears in page).
• tag: the main type, or “tag” of the object, usually a built-in type (see below for a list).

In addition, many objects will also contain:

• tags: an optional set of additional, explicitly assigned tags.
• itags: a set of implicit or inherited tags: including the object’s tag, tags as well as any tags assigned to its containing page. This is useful to answer queries like, “give me all tasks on pages where that page is tagged with person“, which would be expressed as query[[from index.tag "task" where table.includes(_.itags, "person")]] (although technically that would also match any tags that have the #person explicitly assigned).

Beside these, any number of additional tag-specific and custom Attribute can be defined (see below).

Tags

Every object has a main tag, which signifies the type of object being described. If you’re familiar with SQL databases, you can think of these as tables, or in object-oriented parlance you can think of them as classes. In addition, any number of additional tags can be assigned as well via the tags attribute. You can use either the main tag or any of the tags as query sources in Space Lua/Lua Integrated Query — examples below. ${index.}

Built-in tags

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