[x3d-public] ProtoInstance USE without name

[Andreas Plesch]

Adding the name ProtoInstance attribute to the joint, segment and site USE
ProtoInstances would be really straightforward since it would mean just
adding name="Joint" etc. This is more similar to regular nodes since for
those the type of the regular node is also given (by the name of the tag):

<ProtoInstance name="Joint" USE="rightElbowJoint" />
<Transform USE='rightElbowTrafo" />

If X_ITE does not like name and USE attributes together, that is ok since
the spec does not require it. I just thought the spec. should explicitly
allow _omitting_ the name attribute since it otherwise but implicitly
implies that the name attribute is generally required. Remember that
"ProtoInstance" is not a node, it is just a statement. "<ProtoInstance
name='theNode' ..>" could be considered a x3d node.

In the meantime I added a workaround to x3dom to digest USE ProtoInstances
without name values fairly sensibly.

-Andreas

On Sun, Nov 22, 2020 at 8:23 PM John Carlson <yottzumm at gmail.com> wrote:

> That's okay if you're generating XML from an authoring tool, but adding
> name to the ProtoInstances in the segment, joint and site containerField
> HAnim sub-objects by hand would be a pain in the neck (it's already a pain
> in the neck to add containerField for every node in XML). So probably, one
> shouldn't require a name.  What I can do is look up the name in X3DJSONLD
> perhaps, and add the name to the right nodes?   So JSON wouldn't require
> names, and X3DOM would be provided with names by X3DJSONLD?  So that would
> save X3DOM the lookup?   We'll either have to do the USE->DEF lookup to
> find names in either JSONParser.js (X3DJSONLD) or some other place in
> X3DOM. What's the best place?  We need to do JSON schema processing in
> X3DJSONLD. I believe that there are a few cases where having a USE does not
> exclude.
>
> On the other hand, if USE implies the code does not create a duplicate
> data structure, why are we worrying about putting in a name when it should
> be already present in the node?  Does creating a single node for DEFs and
> USEs with the same value mean there's more than one reference to the name
> in X3DOM?
>
> Perhaps we should write a real JSON parser for X3DOM instead of
> translating to XML/DOM?  Something to think. about, however, perhaps VRML
> is higher on the stack of things to do?
>
> John
>
> On Sun, Nov 22, 2020 at 6:46 PM Andreas Plesch <andreasplesch at gmail.com>
> wrote:
>
>> Yes. I was saying these are the only Proto examples I came across which
>> do have USE without a name. To me it would be clearer and more similar to
>> regular nodes if name would be always added, perhaps even required (even
>> though not strictly necessary).
>>
>> Andreas
>>
>> On Sun, Nov 22, 2020 at 6:21 PM John Carlson <yottzumm at gmail.com> wrote:
>>
>>> I'm not finding any name's and USE's together in ProtoInstance node in
>>> the LOA*.x3d examples from the HAnim 2 part 1 spec.
>>>
>>> grep ProtoInstance LOA*x3d|grep USE|grep name
>>>
>>> John
>>>
>>> On Sun, Nov 22, 2020 at 5:02 PM Andreas Plesch <andreasplesch at gmail.com>
>>> wrote:
>>>
>>>> Looking at why the old Prototypes for HAnim did not work properly for
>>>> x3dom, I found that the xml examples typically have a ProtoInstance
>>>> statement with a USE attribute but without the corresponding name attribute
>>>> defining the actual node type. However, x3dom expects a name attribute with
>>>> every ProtoInstance statement, even USE ones, to be able to insert the
>>>> appropriate node.
>>>>
>>>> The xml spec  at
>>>>
>>>>
>>>> https://www.web3d.org/documents/specifications/19776-1/V3.3/Part01/concepts.html#ProtoInstanceAndFieldValueStatement
>>>>
>>>> does not address USE of ProtoInstances but all examples always have a
>>>> name attribute.
>>>>
>>>> Also, in my quite extensive testing of Protos, I did not come across
>>>> other examples of ProtoInstance elements without a name attribute.
>>>>
>>>> To be fair, the name attribute is not strictly necessary for USE
>>>> ProtoInstances since the type of the inserted node can be determined from
>>>> the referenced DEF node. But having the name attribute makes ProtoInstance
>>>> elements more similar to regular nodes. So I think not requiring the name
>>>> attribute for USE ProtoInstances should be explicitly allowed in the xml
>>>> spec., but still be encouraged.
>>>>
>>>> I do not think the xml spec. would be otherwise affected by V.4 ?
>>>>
>>>> Best, Andreas
>>>>
>>>> --
>>>> Andreas Plesch
>>>> Waltham, MA 02453
>>>> _______________________________________________
>>>> x3d-public mailing list
>>>> x3d-public at web3d.org
>>>> http://web3d.org/mailman/listinfo/x3d-public_web3d.org
>>>>
>>>
>>
>> --
>> Andreas Plesch
>> Waltham, MA 02453
>>
>

-- 
Andreas Plesch
Waltham, MA 02453
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