<content>
 <dataRef name="token"/>
</content>

tei_teidata.pattern = token

: A regular expression, often called a pattern, is an expression that describes a set of strings. They are usually used to give a concise description of a set, without having to list all elements. For example, the set containing the three strings Handel, Händel, and Haendel can be described by the pattern H(ä|ae?)ndel (or alternatively, it is said that the pattern H(ä|ae?)ndel matches each of the three strings)

This TEI datatype is mapped to the XSD token datatype, and may therefore contain any string of characters. However, it is recommended that the value used conform to the particular flavour of regular expression syntax supported by XSD Schema.