12.5. Datatypes
A data type defines what counts as a valid value for an attribute. For example, a data type might specify that an attribute value is plain text, a single token (no spaces), a list of tokens, a number, a reference (pointer) to something else, or one choice from a controlled list (an enumeration). Data types are one of the ways TEI Lex-0 turns ‘good advice’ into something a validator or editor can actually check.
Some data types will expect a single token, as in <sense xml:id="s1"/> because the value of @xml:id must be a single, white-space token); while others will accept a space-separated list of tokens, as in <cit type="example" corresp="#s1 #s2"/>, because the data type of @corresp, which is defined in the attribute class att.global.linking, expects one or more references separated by spaces, not commas or semicolons.
Because Lex-0 is based on TEI P5, many data types come from TEI’s general infrastructure. Lex-0 may also narrow or recommend particular value patterns for dictionary-specific interoperability.
You will usually encounter a data type indirectly: when you look up an element and its attributes or via an attribute's membership in an attribute class.
