[X3D-Public] [X3D] containerField is should or must ?

[Joe D Williams]

> point of information:  it is generally not possible to be strict 
> about allowed containerField values in the X3D DTD or X3D Schema. 
> if i recall correctly, that is because it was difficult to do this 
> properly with inheritance.

That is fine, Don. dtd would not do it.
I would just like to look at this as if the allowed containerField 
value is already given explicitly in the structure and organization of 
the schema. That is, much in the same way an advanced xml schema 
processor is probably capable of producing something similar to

http://www.web3d.org/x3d/specifications/ISO-IEC-19775-1.2-X3D-AbstractSpecification/Part01/concepts.html#f-Objecthierarchy

the object hierarchy diagram from the schema input, an advanced xml 
schema processor could read the schema (finding allowed containers 
without containerField) to find the allowed container node(s) by 
examination without need for the containerField and enumerated allowed 
value(s). I think (hopefully rather than from perfect current 
knowledge) the xml schema structure has enough info about this item 
(sort of like reverse inheritance?) is available without the need for 
containerField.

But, since xml processors were not smart enough then and maybe not 
even now about this type of inference for validation, and due to proto 
first node needs, we got ahead using containerField. Still, not as bad 
as if we would have been stuck with something like:

...
<geometry>
  <Box />
</geometry>
...

or whatever the old nickname of that container node structure 
suggestion was.

Thanks Again and Best Regards,
Joe