Span is metadata which indicates the start and end positions.
A wrapper type that attaches a Span to a value
The set of metadata that can be associated with a value
A wrapper type that attaches a Tag to a value
A “Text” is like a string except that it can be cheaply cloned.
You can also “extract” subtexts quite cheaply. You can also deref
&Text into a
&str for interoperability.
Anchors represent a location that a value originated from. The value may have been loaded from a file, fetched from a website, or parsed from some text