Proposed N-Triples changes for datatypes & (untidy) literals

I've bunched these up. There are still some decisions pending, since
these depend on what the abstract syntax will say.

Dave


Adding datatyped literals
=========================
Change 1

FROM
literal ::= langstring | xmlString
TO
literal ::= langstring | xmlString | datatypeString


Change 2

ADD
datatypeString ::= uriref '"' string '"'

OR

Change 3 (if datatypes can have language)

ADD
datatypeString ::= uriref '"' string '"' ( '-' language )?


Adding untidy literals (and bnodes are required)
================================================

Change 4

FROM
langString ::= '"' string '"' ( '-' language )?
TO
langString ::= ( nodeID )* '"' string '"' ( '-' language )?


Change 5

FROM
xmlString ::= 'xml' langString
TO
xmlString ::= ( nodeID )* 'xml' langString


Restricting xml language to 1+ characters
=========================================

No change needed, existing definition is correct:

language  ::=  ( character - ( '.' | ws  ) )+
  and containing any allowed xml:lang content as defined in
 http://www.w3.org/TR/REC-xml#sec-lang-tag