Re: [xml-dev] The edge of chaos: where syntax ends and interpretation be

[Norman Gray <norman@astro.gla.ac.uk>]

Roger and all,
On 2012 Feb 29, at 14:59, Costello, Roger L. wrote:

> Norman Gray wrote:
> 
>    That application has almost complete freedom to 
>    decide what the meaning of those bits of information is.
> 
> Can different meanings be given to the same XML?
> 
> Is it necessary for all who consume an XML document to interpret it the same way? 
> 
> Is a uniform, global interpretation possible?
> 
> Is a uniform, global interpretation desirable?

I'll just throw in here that the word 'application', in this context, doesn't necessarily mean a bit of software.

The XML spec defines an application as a 'module', on behalf of which the 'XML processor' is doing its parsing, which does suggest a bit of software; the XML schema spec is consistent with a slightly broader sense of 'application'; and floating around in the XML genome is the SGML standard's definition of a 'text processing application' as "a related set of processes performed on documents of related types", which doesn't limit those processes to anything involving computers.  The DTD is part of the 'application'.

Saying "let's solve this problem with XML" could be taken to be, by itself, an 'application' of XML (at only a mild stretch).

All of that is a long way of saying that the DTD documentation is part of the application.  That documentation gives _a_ meaning to the elements that are defined: because this is the meaning attached to the elements by the person who made them up or 'owns the namespace', it certainly has some weight; but I don't think one can say that this is the _only_ true meaning.  If I send you a document which uses DTD foo.dtd, then it is certainly reasonable for you to take from that document the meanings indicated by the documentation for foo.dtd, but perhaps I'm mad, perhaps I'm confused, or perhaps one of us has forgotten an out-of-band agreement we made about how we'd cleverly repurpose the foo.dtd elements.  And, as others have said, this is the domain of agreements, contracts, and bitter recriminations.

And all of _that_ is a long way of saying that all of your questions are, I think, variants of a question to which the answer is "this is not XML's problem".

XML is just syntax; meanings are added by some completely separate human process.  Once you find a 'global interpretation', you can do world peace as an encore.

All the best,

Norman


-- 
Norman Gray  :  http://nxg.me.uk
SUPA School of Physics and Astronomy, University of Glasgow, UK