Define an attribute to be used by extensions to mark their elements as following the rules of a Construct defined in the Atom specification.





Add the an appropriate point in the Atom format specification:

X.X.X. atom:construct attribute

This attribute MAY be used by extension elements to indicate that they follow the
rules defined in this specification for some type of Construct. The value of this
attribute MUST be one of "link", "date", or "person". The value MUST be lowercase.
Elements containing this attribute MUST include all of the attributes and child
content required by this specification for the named Construct type. They MUST NOT
contain additional attributes or child content which is required in order to
process the element in an acceptable manner.

Example: The following indicates that myext:mylink is a Link Construct, as defined
by this specification:

<myext:mylink atom:construct="link" rel="my-rel-value" href="" />



If @rel is required for Link Constructs, and the list of acceptable values is closed, an extension Link Construct wouldn't be able to add @rel values. If this proposal is adopted and we decide to close the @rel value list, we should close this @rel value list for the atom:link element, but not for Link Constructs.