Re: [RIF] homework for 10/17 telecon

> On Mon, 2006-10-16 at 09:39 -0400, Michael Kifer wrote:
> > 
> > > However, it was the example itself which left me with the (apparently 
> > > mis-)understanding that this was still work in progress since the 
> > > terminals in there don't meet our needs. For example, we require that 
> > > functions and relations be identifiable with URIs - I see no URIs, 
> > > qnames or curis in that example. We need typed literals of some form and 
> > > whilst there has been some discussion on that as a result of DanC's 
> > > questions I see nothing those pages that suggests what the final 
> > > proposed approach is. That example includes a constant "$49" which I 
> > > have assuming is a place holder for some structured value mean to be a 
> > > integer with an associated currency tag. The variables will need meet 
> > > W3C i18n standards and I see no part of that sketch which explains the 
> > > i18n approach.
> > 
> > Yes, you are right. The original syntax had IRIs, but several weeks ago
> > there was a decision at a telecon to first specify an unsorted logic.
> 
> Was that a WG decision, or just advice to the editors? If it was
> a WG decision, I'd appreciate a pointer to the record.

It was not voted on as far as I remember. So, you can call it an advise to
the editors.

> > Data types (IRIs being one of them) will be later introduced as sorts.
> 
> I don't understand how sorted/unsorted is relevant to the syntax
> of identifiers.
> 
> I see...
> 
> "In the present version, variables are not sorted and thus can range
> over all constants, Data or Ind."
>  -- http://www.w3.org/2005/rules/wg/wiki/A.1_Basis%
> 253A_Positive_Conditions
> 
> Dave, I suggest that <Ind> is what you're after if you want to
> use URIs for names. I find it a little awkward that not all names
> are URIs, but I can perhaps live with that; I'll probably treat
> the non-uri names as local fragment identifiers or something.
> 
> The constant "$49" is just a string, as far as I can tell
> from Harold's explanation of Fri, 13 Oct 2006 23:29:51 -0400 .
> http://lists.w3.org/Archives/Public/public-rif-wg/2006Oct/0044.html

Sorts in a logic always imply some special syntax.
Formally, this just means that one or more sorts are attached
to every symbol. But in a concrete KR language it means that
literals, vars, functions, and predicates that belong to different sorts
should be somehow identified syntactically.
This is easy in XML, but is typically more cumbersome in human-oriented
(or, as you called it, programmer-oriented) syntax. So, languages for
symbolic manipulation are often unsorted or sorted only partially.


	--michael  

> 
> As to URIs for functions or relations, I'm not sure; so far,
> I have only found a need for URIs as constant symbols.
> 
> > You should realize that this is just a first step. There are many more
> > details to be worked out, such as builtins, data types, etc.
> > 
> > 
> > 
> > 	regards
> > 	  --michael  
> -- 
> Dan Connolly, W3C http://www.w3.org/People/Connolly/
> D3C2 887B 0F92 6005 C541  0875 0F91 96DE 6E52 C29E
> 
>

Received on Monday, 16 October 2006 14:15:33 UTC