XML complexity, namespaces (was WG)

[David Megginson]

Rick Jelliffe writes:
 > 
 > From: David Megginson <david at megginson.com
 > 
 > >In SGML, you have to write a special program to act on the information
 > >in the data attributes (nothing does this out of the box); in XML, you
 > >have to write a special program to act on the PUA.
 > 
 > Huh? OmniMark allows access to data attributes just as easily as element
 > attributes (http://www.omnimark.com/develop/om40/doc/concept/646.htm),

Yes, so does SP.  But (with the exception you note below) you still
have to write an Omnimark or Perl or C++ program to act on the
information in the data attributes.

 > out of the box. Several CALS-aware tools understand the notations used
 > in data attributes, e.g.,  when used for graphics.

I agree that there are some tools already written that understand
specific data attributes in specific cases, but the general case, you
still have to write a specialised program (using Omnimark, Perl, or
whatever) to do something useful with the data attributes, just as you
have to write a specialised program (using Java, Perl, or whatever) to
do something useful with PUA characters in XML.

 > And I dont agree that elements and characters and attributes and
 > entities should be thought of as interconvertable: search routines
 > look for character codes--I don't know of any search routines which
 > allow grepping on data and elements.

Perhaps I misunderstood -- I thought that you were talking about the
problem of including specialised, non-canonical characters in
attribute values (say, to represent three variant 'd' graphemes in a
10th-century English manuscript or a customised Han character).  I
think that PUA characters provide a good solution for that problem --
the only difficulty is that all of the knowledge about those
characters has to be encoded in the processing software using a lookup
table, while the SGML data-attribute solution is slightly more modular
since you can pass on extra generic information.


All the best,


David

-- 
David Megginson                 david at megginson.com
           http://www.megginson.com/

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