Re: PIDF - using xml schema

Graham, Adrian, and Wayne,

Thanks very much for your contributions to the PIDF draft. 
And sorry for joining the discussions late.  

I have a couple of comments. 

> > >* draft-ietf-impp-cpim-pidf-02.txt:Section 3.1
> > >
> > >I think we should change this to REQUIRE an XML declaration. We 
> > >should
> > >mandate the use of UTF-8 and recommend that the encoding attribute 
> > >SHOULD be used to explicitly note the use of UTF-8.
> > 
> > I'm not up to speed on the detail issues here, but the XML declaration
> > seems to me rather like excess baggage.  I have a (weak) preference to
> go 
> > the other way; i.e. prohibit it.  (xml-guidelines say to be explicit, 
> > IIRC.)  As for mandating UTF-8, I agree.
> 
> The text that suggested to me that we should have it is:
> 
>    In other cases, the XML is a larger component which may
>    find its way alone as an external entity body, transported as a MIME
>    message.  In those cases, the XML declaration is an important marker
>    and useful for reliability and extensibility.

What do you mean by "We should mandate the use of UTF-8"? 

Because PIDF is encoded in XML, all the processor for PIDF MUST be able to 
handle UTF-8.  Also, XML allows other encodings by specifying it explicitly.
So, I agree that we should be explicit that all the implementation is mandated to
understand UTF-8.  But, I you are saying other encoding should not be allowed,
I would object.  I hope hot. 

As for mandating the XML declarations, I would second Adrian's opnion because
it makes the XML document self-contained.  I think this is a desirable feature 
because presence information documents may be stored and reused by some 
implementations. 

> > >* draft-ietf-impp-cpim-pidf-02.txt:Section 4.4
> > >
> > >Rather than the DTD, we should use an XML schema and insist that PIDF
> > >documents MUST be valid according to the schema.
> > 
> > Again, I'm not up to speed on the subtleties.  But IIRC, XML schema 
> > handles
> > the extensibility more smoothly so might be a better choice.  I think
> it is 
> > worth leaving the DTD in as a (non-normative) appendix because many
> folks 
> > are more familiar with that.  If nothing else, it will help these
> folks to 
> > understand the schema.
> 
> That sounds fair enough. I sit in the other camp and have no real idea
> when it comes to DTD's :o).

Okay, I agree with this change.  

So, can we agree to go with the Wayne's contributions?   If yes, I will edit the 
draft based on his XML schema definitions and examples.  But, anyway, we 
should carefully look at them before the change.  


-- Hiroyasu Sugano



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