Chapter 4. Patterns and Structures Common to All TAN Encoding Formats

Table of Contents

Common Patterns
IRI + name Pattern
Digital Entity Metadata Pattern
Edit Stamp
Overall Structure
@id and a TAN file's IRI Name
Metadata (<head>)
Rights and Licenses
Keys and Inclusions
Distinguishing <source>s and <see-also>s
Attribute inheritability and priority
Defining Words and Tokens

This chapter provides general background to the elements and attributes that are common to all TAN files. For detailed discussion of individual elements and attributes, see Chapter 8, TAN patterns, elements, and attributes defined.

This chapter has no relevance for TAN catalog files. For an explanation of that format, see the section called “TAN Catalog Files (collection)”.

Some entities identified by the the section called “IRI + name Pattern” will be digital resources. In those cases, the IRI + name Pattern is extended in two different ways, according to whether the entity is a TAN file or not.

If the entity is a TAN file, then <IRI> (one and only one) must be a valid tag URN that matches the @id value of the TAN file being referred to. This may seem excessive, since in other contexts (HTML, TEI), one need only the @href or @src. This extra measure has been introduced because TAN files are meant to be valid long after their creation, when they may be separated from their original context, or when a server no longer has the files referred to. Without the @id value, recovering the referred to file would be difficult or impossible; with it, easier, and perhaps possible.

If the entity is not a TAN file, then any IRI may be used. If you choose to use the digital resource's URL as its name (and as its location; see below), then it will be inferred that you mean to identify the digital resource that appeared at that URL at the date or time you accessed it.

In either case, the pattern adds to the IRI + name pattern one or more <location>s and an optional <checksum>.

Most TAN elements allow for an optional edit stamp, an @ed-who and an @ed-when, stating who created or edited the enclosed data and when. Neither attribute is allowed without the other.

@ed-when, along with @when and @when-accessed, are the attributes through which a TAN file's version is calculated. The latest date serves as the version number.

An edit stamp performs the same function as <change>, except that no description can be provided, and it points precisely to the element where a change has been made. If a description of the alteration is necessary, <change> should be used.