W3C home > Mailing lists > Public > www-rdf-comments@w3.org > July to September 1999

Question about the abbrev. RDF:Alternative grammar syntax

From: Renato Iannella <renato@dstc.edu.au>
Date: Fri, 06 Aug 1999 09:42:21 +1000
To: www-rdf-comments@w3.org
cc: Hoylen Sue <hoylen@dstc.edu.au>, Zhimin Zhan <zzhan@dstc.edu.au>
Message-ID: <127174.3142921341@columbus.dstc.edu.au>
---------- Forwarded Message ----------
Date: Fri, 6 Aug 1999 9:29 AM +1000
From: Zhimin Zhan <zzhan@dstc.edu.au>

While I was developing a RDFParser based on the latest RDF syntax
specification ( REC-rdf-syntax-19990222, W3C Recommendation), I was
confused by the abbreviated  alternative grammar syntax in statement [6.27]:

  alternative ::='<rdf:Alt' idAttr? memberAttr? '/>'

Note: memberAttr? - 0 or 1 member.

My understanding of RDF, the alternative should have at least only
one member, like its non-abbreviated grammar ( using + ):

  alternative    ::= '<rdf:Alt' idAttr? '>' member+ '</rdf:Alt>'

Could you clarify this? thanks. 

Excerpt from REC-rdf-syntax-19990222:

  [6.26] bag         ::= '<rdf:Bag' idAttr? '>' member* '</rdf:Bag>'
                          | '<rdf:Bag' idAttr? memberAttr* '/>'
  [6.27] alternative ::= '<rdf:Alt' idAttr? '>' member+ '</rdf:Alt>'
                          | '<rdf:Alt' idAttr? memberAttr? '/>'
  [6.31] memberAttr  ::= ' rdf:_n="' string '"' (where n is an integer)


regards,
Zhimin Zhan

----------------------------------------------------------------
Zhimin Zhan (zzhan@dstc.edu.au)                             .
Software Engineer, Resource Discovery Unit              _--_|\
DSTC Pty Ltd, Level 7 General Purpose South	       /     DSTC 
The University of Queensland, QLD, AUSTRALIA 4072      \_.--._/
Phone: +61 7 3365 4537 Fax: + 61 7 3365 4311                v

---------- End Forwarded Message ----------
Received on Thursday, 5 August 1999 19:41:57 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Friday, 21 September 2012 14:16:27 GMT