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RE: UPDATED: Pointers changes and issues

From: Carlos Iglesias <carlos.iglesias@fundacionctic.org>
Date: Wed, 18 Jul 2007 15:10:22 +0200
Message-ID: <09700B613C4DD84FA9F2FEA521882819023BDEFA@ayalga.fundacionctic.org>
To: "Johannes Koch" <johannes.koch@fit.fraunhofer.de>, <public-wai-ert@w3.org>


Hi again,

> >>> 2.3.4 CharOffsetPointer Class
> >> [...]
> >>> ISSUE #6: We can think about merging this one and the
> >> following ByteOffsetPointer Class into a single 
> OffsetPointer Class.
> >>> ptr:CharOffsetPointer (rdfs:subClassOf ptr:SinglePointer)
> >>>     // number of characters from the start of the reference
> >>>     ptr:charOffset (rdfs:range rdf:Literal)
> >> Which property/properties would the OffsetPointer have? If 
> it's only 
> >> a ptr:offset property, how to distinguish between a 
> character or byte 
> >> offset? 
> > 
> > Only ptr:offset and the inherited ptr:reference, so the distinction 
> > would come from the context (the scope within which the pointer 
> > operates)
> 
> Could you please elaborate?


ptr:OffsetPointer
|- ptr:reference (rdfs:range rdf:Resource)
|- ptr:offset (rdfs:range rdf:Literal)

Was thinking about infering the offset type from the Resource type, but may be quite restrictive and tricky.

 
> >>> 2.4.3 CharOffsetRangePointer Class
> >> [...]
> >>> ISSUE #13: We can think about replacing the Literal value
> >> with a CharOffsetPointer single Pointer (or a new generic 
> >> OffsetPointer as seen at issues #6 and #8) [...]
> >>> 2.4.5 ByteOffsetRangePointer Class
> >> [...]
> >>> ISSUE: #15: We can think about replacing the Literal value
> >> with a ByteOffsetPointer single Pointer (or a new generic 
> >> OffsetPointer as seen at issues #6 and #8)
> >>
> >> Wouldn't that make the CharOffsetRangePointer and 
> >> ByteOffsetRangePointer equal to the RangePointer?
> > 
> > I don't see your point here.
> 
> What is the difference then between
> ptr:CharOffsetRangePointer
> |- ptr:charOffset (rdfs:range ptr:ByteOffsetPointer)
> 
> and
> 
> ptr:RangePointer
> |- ptr:endPointer (rdfs:range ptr:SinglePointer)
> 
> ? Both are pointing to the end of the range.

Yes but in a different way: a start point and an end point or a start point and a length (offset).

> If you want to _point_ to the end of the range, you can use a 
> RangePointer. I though the intention of the 
> CharOffsetRangePointerByteSnippetRangePointer was to specify 
> the _length_ of the range.

I'm sorry but I don't get you yet. You'll still have a lenght (offset) from the start point (that may be the beginning of the document or other start point)

ptr:CharOffsetRangePointer
|- ptr:startPointer (rdfs:range ptr:SinglePointer)
|- ptr:charOffset (rdfs:range ptr:ByteOffsetPointer)
|--- ptr:reference (rdfs:range rdf:Resource)
|--- ptr:byteOffset (rdfs:range rdf:Literal)

ptr:RangePointer
|- ptr:startPointer (rdfs:range ptr:SinglePointer)
|- ptr:endPointer (rdfs:range ptr:SinglePointer)

In fact I've just realized that we "have" to use a ByteOffsetPointer instead of a Literal, because otherwise we don't have any ptr:reference and we need it.

Regards,
 CI.
 
--------------------------------------

Carlos Iglesias

CTIC Foundation
Science and Technology Park of Gijón
33203 - Gijón, Asturias, Spain 

phone: +34 984291212
fax: +34 984390612
email: carlos.iglesias@fundacionctic.org
URL: http://www.fundacionctic.org
Received on Wednesday, 18 July 2007 13:10:08 GMT

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