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RIF lists question referring to ourt last telecon discussion

From: Axel Polleres <axel.polleres@deri.org>
Date: Sun, 20 Sep 2009 08:40:33 +0100
Message-Id: <E918097A-0E62-449A-B451-72D92A8DF04F@deri.org>
Cc: Sandro Hawke <sandro@w3.org>
To: "RIF (E-mail)" <public-rif-wg@w3.org>
Started to clean up DTB wrt. List functions and predicates... cf.  
ACTION-920

Question: Is

  External( pred: is-list( List ( 1 | 2 ) ) )

true or false or undefined? From the current informal definition this  
is not clear.

I adapted the definition of
   http://www.w3.org/2005/rules/wiki/DTB#pred:is-list
assuming the former.
Further, I added the following examples to the definition of is-list  
in DTB:

    is-list(List(0 1 2 | List(3 4))) = True
    is-list(List(1 | 2)) = True

BTW, this is not RIF syntax, so the examples for lists in the document  
need to be
in proper RIF presentation syntax,  ie. instead it should be:

   External(pred:is-list(List(0 1 2 | List(3 4)))) will evaluate to t  
in any interpretation.
   External(pred:is-list(List(1 | 2))) will evaluate to t in any  
interpretation.


I am not sure whether I manage to clean up all list functions, but I  
think we cannot have
examples in the document which aren't valid for any syntax we support,  
so at least the examples should be cleaned up.
Given ambiguities of the informal mappings like thes further convinces  
me that it we
probably don't want the informal mappings in the spec. Opinions?
(I am still not sure how far I get with the cleaning...)


Axel



-- 
Dr. Axel Polleres
Digital Enterprise Research Institute, National University of Ireland,  
Galway
email: axel.polleres@deri.org  url: http://www.polleres.net/
Received on Sunday, 20 September 2009 07:41:15 GMT

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