please define "a white space separated list" in the RDFa Core spec

Please consider this a formal comment on the RDFa Core spec at
http://www.w3.org/TR/2013/PER-rdfa-core-20130625/

Comment:
Please add to the spec an unambiguous definition of exactly what the term
"white space separated list" means, and change the places in the spec that
use that term into hyperlinks to the definition.

Context:
I've implemented support for validating RDFa in HTML in the W3C validator
and found that the spec is unclear about whether or not particular
attribute values are allowed to contain leading/trailing whitespace; that
is, whether values containing leading and/or trailing whitespace are valid
or instead should be reported as errors.

The specific cases I mean are the datatypes for the values of several
attributes defined in the RDFa Core spec that make reference to the term "a
white space separated list"; e.g., "a white space separated list of
prefix-name IRI pairs". The problem is that the spec never actually clearly
defines what a valid "white space separated list" is.

It appears from reading other parts of the spec that what the spec refers
to as "a white space separated list" is intended to mean not just that the
list items are separated by whitespace but also that the list can have
leading and/or trailing whitespace. But if so the fact that it's intended
to mean a list that can have leading/trailing whitespace is not obvious
from just the term "a white space separated list".

The part of the spec that makes me assume it's intended to mean there can
be leading/trailing whitespace is the "White space within attribute values"
section at http://www.w3.org/TR/rdfa-syntax/#white_space

But that section just says, "When attributes accept a white space separated
list of tokens, an RDFa Processor must ignore any leading or trailing white
space." So it's not defining whether leading/trailing whitespace are
actually allowed/valid in "a white space separated list" -- it's only
specifying how one particular conformance class (an RDFa Processor) must
process such a list.

But for the purpose of providing RDFa-in-HTML validation, I'm not
implementing a fully conforming RDFa Processor in my application, and don't
need to. And from the current spec, I can't tell whether or not I should
have my application report the leading/trailing whitespace as an error.
What's more, any RDFa authors reading the spec are also not going to be
able to tell whether or not it's OK to put leading/trailing whitespace in
those attribute values in their documents.

For the sake of comparison, the HTML spec seems to me to do good job of
very clearly specifying syntax for a case like this. It defines something
similar, "a set of space-separated tokens":

  http://www.w3.org/html/wg/drafts/html/master/infrastructure.html#space-separated-tokens

It would be really nice to have a similarly clear definition for "white
space separated list" in the RDFa Core spec.

  --Mike

-- 
Michael[tm] Smith http://people.w3.org/mike

Received on Wednesday, 26 June 2013 16:56:57 UTC