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RE: [xml-dev] "XML Schema specifies just syntax" versus "XML Schema specifies semantics"

I'll venture to assert that John is right and the rest of you (Sally,
Roger, and Liam) are both right and wrong.

To continue baldly asserting (all of this, of course, is IMO):

Roger is mistaken to define semantics as he does. Some significant bits
of semantics can be captured by his sort-of structuralist definition
(which seems to be shared by many in the "semantic"-web community), but
not the most useful bits, which involve irreducible concepts. (Liam is
more right to leave it at "imbue with meaning.")

Liam is wrong in several odd little ways: He says applications can imbue
languages with meanings; he says people are applications; and he implies
that grammars for languages that are semantically arbitrarily flexible
define more than syntax (when he says Sally is wrong--I'm really
nitpicking here). He also appears to confuse XML with XML Schema

But he (along with Sally) is wrong in a more important way. To see why,
consider an example:

<wallaby name='Henrietta'>

Suppose we use XML-S to define a grammar in which this is an acceptable
sequence (in some context[s]).

The best way to argue John is wrong w.r.t. this example is to observe
that one could imbue this fragment with meaning according to the
following interpretation:
* A 'wallaby' describes a specific instance of flooding.
* The wallaby's 'name' attribute specifies a date or date range.
* 'Henrietta' refers to September, 2011.
* A 'zipcode' element contains a US Postal Service Zip Code (either 5-
or 9-digit).
* A 'favorite-food' element identifies a river.
* Within a 'favorite-food' element, 'grass' refers to the Pompton River.

Voila! We have imbued our mini-language with meaning! John is wrong.

But the fact that no one in his right mind would ever assign such an
interpretation to this mini-language should tip us off that John is onto

Namely: When we define the syntax of an XML language, we generally
employ bits of natural languages along the way; we generally do so in
order to imbue our XML with some meaning (semantics) from the get-go;
and we generally do so in a way that leverages the meanings of the bits
of natural language that we employed (as opposed to working at
cross-purposes to those meanings).

Thus our XML schema definitions end up embodying both syntactical and
semantic information.

That is not to say that machines can do much with the semantic
information in the schema. They can't. They can only "check" those
elements of the semantics that inform syntactical relationships--e.g.,
that a wallaby can have a name, a zip code (if it resides in the US),
and a favorite food. (Hence the popularity among computer types of the
semi-structuralist definition of semantics that Roger used.)

FWIW, that's the view of this software engineer who was trained as an
analytic philosopher.

Norm Birkett

> -----Original Message-----
> From: Liam R E Quin [mailto:liam@w3.org]
> Sent: Wednesday, November 09, 2011 11:25 PM
> To: Costello, Roger L.
> Cc: xml-dev@lists.xml.org
> Subject: Re: [xml-dev] "XML Schema specifies just syntax" versus "XML
> Schema specifies semantics"
> On Wed, 2011-11-09 at 19:09 +0000, Costello, Roger L. wrote:
> > Hi Folks,
> >
> > Sally says, "XML Schema specifies just syntax."
> >
> > John says, "XML Schema specifies semantics."
> >
> > Who is correct?
> Neither.
> XML Schema Documents can define a grammar for a language that
> applications (including people) can imbue with meaning.
> The same is true for other syntaxes, such as RDF/Turtle, RDF/N3,
> RDF/XML.  The existence of the last of these is a proof that, if RDF
> can
> convey semantics, and if an RDF graph, once transmitted over RDF/XML,
> and reconstituted, still has the same semantics, RDF/XML can contain
> semantics, and therefore XML can contain semantics (and so can ASCII,
> and so can ethernet electrical signals...).
> Liam
> --
> Liam Quin - XML Activity Lead, W3C, http://www.w3.org/People/Quin/
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