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

[Don Brutzman]

XML encoding examples

1. Empty string array:	

     <Text string=''/>
or
     <Text/>

The construct <Text/>also happens to be X3D XML Canonical Form.

2. String array with single element consisting of an empty string, rendered as a line break:

     <Text string='""'/>

     <Text string=""""/>

     <Text string='""'/>

... etc. for containing whitespace and character-entity variations.

On 5/12/2017 10:36 AM, Yves Piguet wrote:
> Hi Dick,
> 
> Ok, thanks. But that's more related to X3D types, or the Classic VRML encoding which is unambiguous, rather than the XML encoding.
> 
> Yves
> 
>> On 12 May 2017, at 18:13, Richard F. Puk <puk at igraphics.com> wrote:
>>
>> Hi, Yves --
>>
>> What I meant by "originally intended" was that it is consistent with other
>> data types. For example, an MFFloat expressed as [] represents an array with
>> no elements. Similarly, an MFString expressed as [] represents an array with
>> no elements (i.e., no strings). However, an MFString expressed as [""]
>> represents an array with on element consisting of an empty string. Since the
>> implementation of an MFString is often done by providing an array of
>> pointers to the strings in the array, an empty string would have a pointer
>> but no content. I believe that this is what is expressed in both VRML and
>> X3D. Since I participated in all of the discussions back when VRML and X3D
>> were each being designed, I know that consistency of field type was an
>> important factor.
>>
>>   -- Dick
> 


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