RE: [xmlChunk-44] Chunk of XML - Canonicalization and equality

>Personally, I suspect no one notion of deep equality will satisfy
everyone.

I pointed this out in [1].   

/paulc

[1] http://lists.w3.org/Archives/Public/www-tag/2004Jan/0015.html 

Paul Cotton, Microsoft Canada 
17 Eleanor Drive, Nepean, Ontario K2E 6A3 
Tel: (613) 225-5445 Fax: (425) 936-7329 
mailto:pcotton@microsoft.com

  

> -----Original Message-----
> From: www-tag-request@w3.org [mailto:www-tag-request@w3.org] On Behalf
Of
> Elliotte Rusty Harold
> Sent: February 3, 2004 12:22 PM
> To: Williams, Stuart
> Cc: 'www-tag@w3.org'
> Subject: RE: [xmlChunk-44] Chunk of XML - Canonicalization and
equality
> 
> 
> At 3:21 PM +0000 2/3/04, Williams, Stuart wrote:
> >There seems to be some question as to whether xml:lang (and maybe
> xml:base)
> >survive the canonicalisation process. See [1] and thread.
> >
> 
> I don't think there are any questions about this. If I recall
> correctly, they don't unless they're a part of the canonicalized
> chunk in which case they do.
> 
> Perhaps what's being asked is really whether canonicalization
> invented the right semantics for equality. Personally, I suspect no
> one notion of deep equality will satisfy everyone. For instance, in
> my XOM work I do test base URIs for equality (which XML
> canonicalization does not) but consider two bases to be equal if one
> might be a relative form of the other. That's necessary for my unit
> tests to work, but it may well be not what everyone needs all the
> time. Similarly I compare document type declarations when comparing
> documents, which canonicalization doesn't do.
> 
> I don't think the xml:lang and xml:base cases are particularly
> special. As long as you have less than a complete document being
> singed, there could always be ancestor attributes that have meaning
> in a particular local context and which are not signed. For instance,
> imagine a process which uses verified, approved, or confirmed
> attributes to describe the content of an element. If the elements
> descendants are signed without their ancestor it would be easy to
> change any of these from false to true or vice versa. I'm sure you
> can conceive of many similar cases.
> 
> I don't think the predefined semantics of xml:base and xml:lang are
> so special that they are justified in being treated in a different
> way than any other attribute.
> --
> 
>    Elliotte Rusty Harold
>    elharo@metalab.unc.edu
>    Effective XML (Addison-Wesley, 2003)
>    http://www.cafeconleche.org/books/effectivexml
> 
>
http://www.amazon.com/exec/obidos/ISBN%3D0321150406/ref%3Dnosim/cafeaula
it
> A

Received on Tuesday, 3 February 2004 13:42:20 UTC