repeat over specified? data-attributes (of attribute-reference
     element-qualifier*)? as alias-name
     local-declaration*
     action*
  again

An action that can be used to iterate over all attributes that:

• are declared for a notation and,
• are specified in an external entity declaration.

repeat over data-attributes must specify an alias-name following as. This name is used to identify the attribute selected for each iteration within the repeat over action. Any name can be used.

Use of the keyword data-attribute followed by alias-name, without qualifiers, inside the repeat over data-attributesaction always refers to the attribute identified by the alias.