[x3d-public] X3D minutes 5, and 12 March 2012: outreach activity, HAnim, metadata explorations, X3D Ontology, glTF examples

[vmarchetti at kshell.com]

The proposal is to relax the prohibition as described, but I think it would be useful to look at this in another way: A proposal to relax the requirements on a content author is equivalent to adding a requirement on X3D file parsers. In this case, I think the additional requirement on X3D XML encoding parsers/readers is something like:

When reading an MFString value, and the 'normalized value' of the attribute is non-empty, and does not begin and end with quote characters, then the parser is required to parse that value as a single SFString value, and treat the X3D field value as an MFString with one contained SFString.

We can see that this is a non-trivial requirement to express, and I am not convinced that even this has the desired effect.

I also argue that it will be necessary to clarify the specification on the backslash issue to properly make the change this proposal suggests. We will need to give unambiguous answers to how to address these edge cases :

<MetadataString name='test' value='"Hello' />
<MetadataString name='test' value='\"Hello"' />
<MetadataString name='test' value='"\"Hello"' />
<MetadataString name='test' value='"Hello"  ' />

Vince Marchetti



> On Mar 17, 2021, at 4:41 PM, Don Brutzman <brutzman at nps.edu> wrote:
> 
> Thanks Michalis.  Agreed this is important to sort out.
> 
> Difference of opinion:  I think we can safely relax the prohibition as follows
> 
> 	The construct "string3" *is* a valid single-array-value instance of an MFString. Such an MFString can also be properly specified as
> 	'"string3"'
> 	or
> 	'"string3"'
> 	or
> 	""string3""
> 
> This use of a singleton value is already the case for grammar in ClassicVRML encoding.
> 
> 	The construct "string3" is equivalent to [ "string3" ] or simply "string3" in ClassicVRML encoding.
> 
> Clarifications for backslash can always help, I don't have an opinion yet on what you've said.  We do have writeups in Mantis and perhaps-several example test scenes.
> Will continue preparations and put this on weekly agenda in near future, though likely not this week.
> 
> On 3/16/2021 1:16 AM, Michalis Kamburelis wrote:
>> The issue of quoting MFString and SFString in X3D XML encoding was
>> discussed many times on this mailing list :) I have a page with
>> conclusions on https://github.com/michaliskambi/x3d-tests/wiki/Clarify-the-usage-of-quotes-and-backslashes-for-MFString-and-SFString-in-XML-encoding
>> . Let us apply the fix to the spec, I have a ready prose on that page
>> that I believe was "agreed" by various parties a few years ago already
>> :)
>> Regards,
>> Michalis
>> wt., 16 mar 2021 o 07:21 Don Brutzman <brutzman at nps.edu> napisał(a):
>>> 
>>> Attendees  5 March 2021:  Vince Marchetti, Dick Puk, Don Brutzman
>>> 
>>> Attendees 12 March 2021:  Anita Havele, Vince Marchetti, Dick Puk, Don Brutzman
>>> 
>>> We continue to meet Fridays at regular time, 09-1000 pacific.
>>> [...]
> all the best, Don
> -- 
> Don Brutzman  Naval Postgraduate School, Code USW/Br       brutzman at nps.edu
> Watkins 270,  MOVES Institute, Monterey CA 93943-5000 USA   +1.831.656.2149
> X3D graphics, virtual worlds, navy robotics http://faculty.nps.edu/brutzman
> 
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