ACTION-314 (Re: [TED] ACTION-294: Propose a treatment of sequences)

ACTION-314 [1]:


This action is closely related to the ACTION-294 [2], and there have been
extensive discussed during the last two telecons, as well as in the
mailing list.


The original intention of this action is about integrating RIF with XML
Schema list datatypes. In other words, we would like to have some RIF
constants as instances of some XML Schema list datatypes. To do this, we
can extend the current concrete syntax for Const

Const  ::= CONSTNAME | '"'CONSTNAME'"''^^'SORTNAME

into the following form:

Const  ::= CONSTNAME | '"'CONSTNAME'"''^^'SORTNAME |
'"'LEXICAL-FORM'"''^^'LIST-DATATYPES

Note that LEXICAL-FORM allows space. Here is an example list constant
(from [3]): Given the following XMLS list datatype sizes,

<simpleType name='sizes'>
  <list itemType='decimal'/>
</simpleType>

we can have the following list constant:

<cerealSizes xsi:type='sizes'> 8 10.5 12 </cerealSizes>.

In RIF concrete syntax, it is written as

"8 10.5 12"^^sizes.

The list constant can be translated into RDF as follows:

_:1 rdf:first "8"^^xsd:decimal .

_:1 rdf:rest _:2 .
_:2 rdf:first "10.5"^^xsd:decimal .
_:2 rdf:rest _:3 .
_:3 rdf:first "12"^^xsd:decimal .
_:3 rdf:rest rdf:nil .

Note that xsd:decimal is the itemType for the list datatype sizes.

Another point raised in the telecon [4] was on allowing variables in list.
To some extent, this has already in the RIF core:

Uniterm     ::= Const '(' TERM* ')'
TERM        ::= Const | Var | Uniterm

As far as I can see, this already covers most (if not all) cases on using
variables in list. If we don't have any specific use cases to require
extra expressive power, I prefer keeping it simple.

My two cents.

Jeff


[1] http://www.w3.org/2005/rules/wg/track/actions/314
[2] http://www.w3.org/2005/rules/wg/track/actions/294
[3] http://www.w3.org/TR/xmlschema-2/#dt-list
[4]
http://lists.w3.org/Archives/Public/public-rif-wg/2007Jun/att-0062/19-June-07-rif-minutes.html#item4b



-- 

Dr. Jeff Z. Pan (http://www.csd.abdn.ac.uk/~jpan/)
Department of Computing Science, The University of Aberdeen

Received on Tuesday, 3 July 2007 13:58:00 UTC