[xml] Realx NG support with libxml2

[Sylvain Hellegouarch <sh defuze org>]

Hi guys,

I've been playing around with libxml2 and its Relax NG support and I've 
been really pleased it worked so nicely :)

But (yes there is a but) it looks like if I use xmlRelaxNGValidateDoc to 
validate my document against my Relax NG schema, I can only get "0 if 
the document is valid, a positive error code number otherwise and -1 in 
case of internal or API error".

Then I can report to xmlRelaxNGValidErr and have a better understanding 
of the meaning of the returned code.

It s nice but it is not enough sadly.

I mean, basically it tells me that my XML document is or not valid, it 
even tells me why but it doesn't tell me WHERE.

Which means that I cannot report that error at a higher level saying for 
instance "on that particular node your document was not correct". I can 
only say "we detected an error".

I don't know if I'm clear. Anyhow, I have erad the doc, searched on 
google but couldn't found anything to help me out.

Eventually I found the function xmlRelaxNGValidateFullElement and I 
though I could then read my XML document node by node and use that 
function to test each node. So I would be able to find which node is 
corrupted.

Would it be the correct way to do it?

Thanks for any help.
- Sylvain