perfsonar development work

[maxim <>]

Hi Jason, 

 
> 
> The tooling I regularly use claims warning on this, which I 
> have always interpreted as being usable for our 
> [non-validated] purposes.  We could of course re-write the 
> various fragments so the validator is happy, but we loose a 
> little bit of power (i.e. a single 'endPoint' with roles that 
> can be 'src' or 'dst' can lead us to something that has two 
> of either). 
> 
Interestingly enough, the nmtopo.xsd schema at
http://viewvc.internet2.edu/viewvc.py/perl/server/xsd/nmtopo.xsd
uses src/dst elements declaration. Basicaly, what I am asking for is a
single and trusted location 
of the stable and valid RNG(C) and schema instances so it could be utilized
for XML -> API kind of development.
Otherwise, I dont know how different people will agree on what metadata
version to support.I thought having a
schema should server this the best.
 
> 
> The usual problem that will violate this is the choice 
> between attribute and element:
> 
> <element name="foo" value="bar"> vs. <element name="foo">bar</element>
> 
> The 'anyElement' trick also probably allows for an ambigous 
> parse (i.e. 
> an element like <subject> can enter into it's specified 
> pattern, or be picked up by 'anyElement'.
> 
> Because we have never forced strict validation at the code 
> level this hasn't been an issue, but if anyone has 
> suggestions to tighten this up it would be great.  In my 
> opinion it is important to have 'legal' XML more than 
> completely validated XML, the individual implementations know 
> exactly what they need and do a great deal of the rejection. 
> 
> -jason
> 
> 
  The problem is that any more or less modern parser ( Xerces ) will report
this as error and
make any XML binding or for example, the  real time validation  under
xmlbeans java framework  kind of impossible.
Of course some parsers with quasi-xml validation will be fine but  its much
cleaner to start with already valid schema.
I am not arguing to "tighten up" every underlying schema but may be to make
it cleaner. Anyway, the goal of using the 
XML schema is to apply some constraints on the data and without presence of
constraints in the schema one can avoid using schema at all or just use
anyElement everywhere.

--Maxim