[x3d-public] Agenda for X3D WG Open Meeting Wednesday 10th May 2017

[Yves Piguet]

Dick, what do you mean with "originally intended"? Which standard, or which informal proposal by which author?

My reaction was wrt Don Brutzman's suggestion to permit unquoted strings in XML Encoding MFString fields to be accepted as a single-element MFString. Then the empty XML attribute could be interpreted either as an MFString containing a single empty string (following Don) or as an MFString with zero element (following the current X3D XML Encoding standard).

You can add special cases to try and guess the intent of the author and remove any residual ambiguity, but then you end up with something like HTML5 where each "syntax error" has a well-defined outcome thanks to an utterly convoluted description of what a parser is supposed to do. I don't like that, I strongly object to that for X3D. XML provides a rigid framework which can still be easily edited by hand, not a loose format like HTML. But it's only my opinion.

Yves


> On 11 May 2017, at 21:24, Richard F. Puk <puk at igraphics.com> wrote:
> 
> Hi, Roy --
> 
> I think that [""] represents an MFString construct containing one element,
> an empty string. Then [] is an MFString construct that contains no elements.
> I think that this is what was originally intended.
> 
>  -- Dick
> 
> /******************************************
> | Richard F. Puk, Ph.D., President
> | Intelligraphics Incorporated
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> 
> 
> -----Original Message-----
> From: x3d-public [mailto:x3d-public-bounces at web3d.org] On Behalf Of Roy
> Walmsley
> Sent: Wednesday, May 10, 2017 3:58 PM
> To: 'Yves Piguet'; 'Don Brutzman'
> Cc: 'X3D Graphics public mailing list'
> Subject: Re: [x3d-public] Agenda for X3D WG Open Meeting Wednesday 10th May
> 2017
> 
> Hi Yves,
> 
> An empty MFString array would have no values. Now that is an interesting one
> we didn't discuss today!!!
> 
> According to the current standard it would be simply [''], i.e. two single
> quotes or apostrophes. However, if we accept the changes discussed today,
> one of which was that an MFString field with only one value could dispense
> with the outer set of quotes and be encoded as an SFString, then that could
> present a dilemma. It would mean that it could be interpreted as a single
> value, which was the empty string, or an empty MFString array. These are not
> the same things, and so this case would require specific wording in the
> text, for clarity.
> 
> Thanks again, Yves,
> 
> Roy
> 
> -----Original Message-----
> From: x3d-public [mailto:x3d-public-bounces at web3d.org] On Behalf Of Yves
> Piguet
> Sent: 10 May 2017 21:40
> To: Don Brutzman <brutzman at nps.edu>
> Cc: X3D Graphics public mailing list <x3d-public at web3d.org>
> Subject: Re: [x3d-public] Agenda for X3D WG Open Meeting Wednesday 10th May
> 2017
> 
> Excuse me if I've missed it, but how do you specify an empty MFString array?
> If double quotes are optional, '' (empty attribute value) would mean an
> empty SFString, i.e. [""] if an MFString is expected, not [].
> 
> Yves
> 
> 
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