[Nmc-wg] Review of documents

[Jason Zurawski]

>> Now relaxng can be transformed but the transformation isn't
>> formal/unambiguous/two-way, or differently put if you transform from
>> relaxng to xsd and back you are not guaranteed to end up with the
>> same relaxng document.
>
> I was not aware of this. I thought the RELAXNG ->  XSD translation was
> unambiguous.
>
> In case someone later wants to add XSD, perhaps it is useful to note
> this differences and perhaps even suggest how the translation should be
> done.

There are specific cases where the translation program that we were 
using at the time (Sun's MSV - I thought development stopped in 2007 but 
I now see some updates: https://msv.dev.java.net/) could not handle 
conversion properly.  Specifically it is possible in RELAX to construct 
an 'or' type relationship between an attribute and a child element, ex:

   <parent type="something" />

vs

   <parent>
     <type>something</type>
   </parent>

The subsequent XSD document produced by conversion was ambiguous to most 
syntax checkers, but a manual change made the syntax/structure made 
things correct and unambiguous.  This is a tool problem, not a language 
problem.

As for a conversion back to RELAX, I have never attempted to do this so 
Michael is probably more experienced in this area than I am.

-jason