Encoding of Sz Reference Values

A reference is encoded as the actual reference value, and a symbol describing the state of that actual reference value.

Reference = ( ReferenceState String ).

The string contains the actual reference value.

The meaning of the state symbols corresponds to that of the symbols used for the description of link references.

INVALID: The reference value is invalid.
ZETTEL: The reference value is a reference to a zettel. This value is only possible before evaluating the zettel.
SELF: The reference value is a reference to the same zettel, to a specific mark.
FOUND: The reference value is a valid reference to an existing zettel. This value is only possible after evaluating the zettel.
BROKEN: The reference value is a valid reference to an missing zettel. This value is only possible after evaluating the zettel.
HOSTED: The reference value starts with one slash character, denoting an absolute local reference.
BASED: The reference value starts with two slash characters, denoting a local reference interpreted relative to the Zettelstore base URL.
QUERY: The reference value contains a query expression.
EXTERNAL: The reference value contains a full URL, referencing a resource outside of the Zettelstore server.