XML Inclusions

[untereiner]

Describe the issue
For now inclusions are handled by an ad hoc xml element. There is need of a special treatment to use included files.

Proposed cleanup
XML Inclusions (XInclude) is a W3C specification that defines a way to include XML fragments from different sources into a single document. We could use this official mechanism instead of an ad hoc one. What do you think ?

Additional context
n.a.

[cssherman]

This is do-able, but I have a few concerns:

1. Our xml interpreter (pugixml) does not support xi:include natively, so we would have to do this all ourselves
2. The syntax of xi:include isn't as user friendly as our current implementation
3. Validating the included xml files is a bit harder using xinclude, as they aren't required to conform to the parent schema

[untereiner]

This is do-able, but I have a few concerns:

1. Our xml interpreter (pugixml) does not support xi:include natively, so we would have to do this all ourselves

I just saw that: zeux/pugixml#338
It seems weird but yes, we would have to to it

2. The syntax of xi:include isn't as user friendly as our current implementation

aside from the xi: not sure it is very different

<Included>
  <File name="./FieldCaseTutorial3_base.xml" />
</Included>

vs

<xi:include href="./FieldCaseTutorial3_base.xml"/> 

3. Validating the included xml files is a bit harder using xinclude, as they aren't required to conform to the parent schema

I don't understand this concern. Do you have an example ?

[untereiner]

For me a schema makes a whole. There is not parent or child schemas.
Using xinclude in xml files is just a way to break down the complexity of a large document.