Whitespace as a constraining facet?

Hi all,
The Candidate Recommendation added in a new constraining facet called
whitespace, but it doesn't appear to be a facet that does any
constraining.  I'm not even sure if it is a facet (but I'm not an english
language expert by any means).  The whitespace functionality is a lot more
like a processing instruction than a constraining facet.

Having it as a facet introduces problems such as when do you apply it?
Ie, I have a string " dog" (with a leading space).  Is this valid against
the following facets (constraining a string) appearing in this order?
<length value="3"/>
<whitespace value="collapse"/>

What if we now have (excusing the improper Namespace handling):
<simpleType name="B">
  <restriction base = "string">
    <length value = "3"/>
  </restriction>
</simpleType>
<simpleType name = "D" >
  <restriction base = "B">
    <whitespace value = "collapse"/>
  </restriction>
</simpleType>
A text InfoItem that satisfies D must also satisfy B as D is restricting B,
but this is not the case with our example of " dog".

Other problems could possibly arise with the use of the value constraint.
The specs sometimes specify the un-normalized value should be used and at
other times the normalized value.

My main problem is that facets change the _value_space_ that defines valid
values, while a whitespace facet changes the _value_ to test in the value
space.

Is there any pointer to W3C discussions concerning this issue?

cheers,
mick.

Received on Tuesday, 6 February 2001 21:31:00 UTC