Comments on this specification may be sent to email@example.com.
- Section 5.5 step 6 - The text of step 6 reads "If in any of the previous steps a [new subject] was set to a non-null value, it is now used to provide a subject for type values;". This is somewhat misleading. By the time step 6 is reached, there will ALWAYS be a [new subject]. What this step is really about is that if there is an @typeof attribute, it is used to define the types for the [new subject]. This is clearly described in the explanatory text.
- Section 4.1. Document Conformance - In the future it is
possible that RDFa will also be defined in the context of HTML.
Consequently document authors SHOULD use lower-case prefix names
in order to be compatible with current and potential future
- Section 5.5 step 9 - The text of step 9 reads in part "The
value of the [XML literal] is a string created by serializing to
text, all nodes that are descendants of the [current element],
i.e., not including the element itself, and giving it a datatype
of rdf:XMLLiteral.". For the avoidance of doubt, this means in
part that the current default namespace of each descendant
element MUST also be included in the emitted XML literal.
- Sections 5.4.5 and 7 - The text indicates that the
prefix '_' is reserved and is used to create / reference blank nodes
(bnodes). Because this prefix is reserved, authors SHOULD NOT declare a
mapping for the prefix '_' and conforming processors MUST NOT incorporate
such a prefix mapping into the 'list of URI mappings' as defined in
- Section 5.5, step 9 reads in part "The value of the [XML
literal] is a
string created by serializing to text, all nodes that are
the [current element], i.e., not including the element itself, and
giving it a datatype of |rdf:XMLLiteral|." Unfortunately, the
requirements for such a serialized string are not completely clear
it comes to XML Namespaces. For the avoidance of doubt, in future
versions of the RDFa Syntax Recommendation, we expect to indicate
the value of the XML literal SHOULD be serialized Exclusive
XML as defined in [XMLEXC14N].
We advise current implementations
start supporting this use model now, since other participants in
XML tool chain may expect consistent, canonical XML.
Rules for evaluating CURIEs and SafeCURIEs are defined throughout the
Recommendation. For the avoidance of doubt, these rules require at
least the following:
The set of prefix mappings to use when expanding CURIEs to IRIs
provided by the current in-scope prefix declarations of the
element on which the CURIEs are found (see section 7 and section
5.5 step 2).
The URI to use when the 'default' prefix is referenced from a
CURIE (e.g., ':next') is '|http://www.w3.org/1999/xhtml/vocab#'
(see section 7). An RDFa Processor MUST expand CURIEs prefixed
with only a colon using this prefix mapping.
There is no mapping defined when there is no prefix AND no colon
specified (see section 7). Therefore, an RDFa processor MUST
expand non-prefixed CURIEs (however, see reserved terms below).
The prefix '_' is reserved and is used to refer to
blank nodes (bnodes) - see sections 5.4.5 and 7. RDFa
MUST ignore any declaration of a mapping for that prefix.
The reserved terms (defined in section 9.3) are ONLY processed
the attributes rel and rev. All other attributes that take
or SafeCURIEs as values MUST NOT treat reserved words specially.
The datatype definitions are in section 9.1, and the attribute
datatype mappings are in section 9.2.
Prefix declarations are subject to the syntactic restrictions
defined in the Namespaces in XML Recommendation (see section 5.5
step 2). These restrictions include prohibiting the declaration
of a prefix mapping for the special prefix 'xmlns' and limiting
the declaration of the special prefix 'xml' to map to its
pre-defined namespace URI (see the Namespaces in XML
Recommendation, section 3). RDFa Processors MUST behave as if
these restrictions are enforced.
Section 9.3 defines a collection of "reserved word" values. These
values are only interpreted in the context of @rel and @rev. @rel and
@rev have been historically defined to be case-insensitive. Section
does not indicate whether the reserved words are case-sensitive or
case-insensitive. However, Section 5.4.4 does mandate that the use of
these values are required to be mapped to URIs in the XHTML Vocabulary
via fragment identifiers, and fragment identifiers are by definition
case-sensitive. For the avoidance of doubt, a Conforming RDFa
MUST treat the reserved word values as case-insensitive on input, and
MUST transform the values to lower-case when mapping them to URIs in
XML Canonicalization - Version 1.0", W3C Recommendation,
J. Boyer et al.,
eds., 18 July 2002.
Available at: http://www.w3.org/TR/2002/REC-xml-exc-c14n-20020718/