Just require URLs

Carl Hage carl at chage.com
Mon May 31 19:02:42 BST 1999

From:           	"Jonathan Borden" <jborden at mediaone.net>

> Paul Hunter wrote:
> > Using HTTP for URIs sounds intrinsically <em>bad</em> to me.  ...
> No one has offered a hard or
> practical example of an actual problem this creates, aside from offending
> of the sensibilities.

Turn it around-- it would be intrinsically <em>good</em> to require
all namespaces to reference a retrievable document. Any existing 
namespace registry can be mapped into a backwards compatible 
HTTP URL, returning something, e.g. http://isbn.org/isbn/1-57595-
180-0B could return the USMARC data (card catalog) formatted in 
HTML with a link to an XML representation. It serves as a URI as 
well as a source of documentation.

Software that maps hytime namespaces can just as easily map 
http://hytime.org/ namespaces, and software that knows nothing of 
hytime namespaces could follow a URL to find needed info. (Maybe 
manually, but better than nothing.)

I think the URI identifying namespaces and DTDs should be URLs 
not URNs. An XML document without retrievable documentation on 
the DTD should be considered non-compliant. The biggest problem 
isn't syntax-- it's the semantics. XML validators based on DTDs will 
only identify an insignificant percentage of errors-- hardly worth it if 
you ask me unless debugging software. (Though considering how 
Microsoft and Netscape callously violate HTML standards, I may 
need to recant.)

Likewise, a DTD->HTML converter doesn't produce human readable 
documentation, because the most important part (semantics) is 

If you ask me, XML will really work only when XML-Schema (or 
whatever) is enhanced to include human-readable detailed 
documentation (with all code-values defined in an XML thesaurus),
and the URIs in XML/DTD headers lead to a retreivable version of 
this. Putting the semantics and code-value definitions in separate 
paper documents (the norm today) must be abandoned. Instead 
everything needed should be accessable at the other end of the 
namespace URL.

Carl Hage                                              C. Hage Associates
<mailto:carl at chage.com> Voice/Fax: 1-408-244-8410      1180 Reed Ave #51
<http://www.chage.com/chage/>                          Sunnyvale, CA 94086

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