::scr Ramblings of a Classic Refugee or How I Learned To Stop Worrying and Love OS X

[Andy Wardley]

On Wed, Feb 06, 2002 at 10:03:15AM -0000, Simon Kinahan wrote:
> Err. No. And you were doing so well, too. Nothing on the other side of teh
> sceen *ever* ascribes human meaning to anything else. And XML Schema
> certainly don't. 

XML Schema defines concepts like year, month, timeDuration, etc., 
that intentionally represent the equivalent human concepts.

Here, let me quote from the spec:

XML Schema Part 2 : Datatypes

  3.3.27 date

  [Definition:] date represents a timePeriod that starts at midnight of a 
  specified day and lasts until midnight the following day.  The value space 
  of date is the set of Gregorian calendar dates as defined in 5.2.1 of
  ISO 8601.    ...etc...

It goes on to define month, year, day, etc., in the same terms.  These
explicitly state that if you use a 'year' datatype in an XML schema then
it equates to the human concept of a 'year'.  

Note the subtle but important difference between 'integer' and 'year'.  
The former is indeed an abstract number which has no human meaning.
But the latter, even though it may be encoded as an integer, has additional
human meaning prescribed by relevant definition in the XML Schema 
specification.

> All they do is define relationships between parts of
> documents, just like DTDs, but much more needlessly complicated and
> laborious. 

No, I'm afraid you've missed an important distinction between a DTD (which
can only describe structure) and an XML Schema (which can describe structure
*and* content).

> Humans ascribe meaning. Some animals might. Nothing else does.

Yep, that's right.  And a bunch of humans got together and said "we'll 
ascribe *this* meaning to *that* concept".  They did it once when calling
a collection of days a "year" (assigning an english word to a human concept)
and they did it again when they said that an XML Scheme 'year' datatype 
would indicate the same concept (assigning an XML word to a human concept).

So yes, it is *humans* that ascribe meanings, but it is also entirely valid
to state that an XML Schema can encode those human concepts in an unambiguous
manner.

A