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Annexes
For the first instance with id equal "iOI" we can use the implied default value of
dirn to indicate that this point is two dimensional and do not have to give this explicitly. The second instance has all attributes filled in.
The tokenised attribute types has special restrictions on the allowed characters and
theyare:
Table c.l. DTD attribute types
XMLType
ID
IDREF
IDREFS
ENTITY
ENTITIES
NMTOKEN
NMTOKENS
Semantics
An identifier for the element that, if specified, must be unique within the
XML document. The value ofthe identifier must always start with a letter,
"_" or ": ". An XML element can only have one attribute oftype ID.
A reference to an XML element in the XML document. The value must correspond to an attribute value oftype ID in an existing XML element.
A reference to one or more XML elements. The values must be separated by
spaces and must correspond to existing XML element ID's.
A reference to an extemal entity. The value must be a legal entity name.
A reference to any number of entity names, where the entity names are
separated by spaces.
A NMTOKEN (Name Token) is any mixture of characters.
Any number ofNMTOKENs separated by spaces.
Some attributes are specific for XML and have reserved names and well-defined
semantics. The xrnl:lang attribute can be used to indicate the language used in XML
elements and xrnl:space can be used to indicate how to handle whitespace within
elements.