From: hal@finney.org
Date: Thu Dec 07 2000 - 00:47:16 MST
Michael M. Buttler quotes Ted Nelson at
http://www.sfc.keio.ac.jp/~ted/TN/WRITINGS/TCOMPARADIGM/tedCompOneLiners.html
> "The Xanadu® project did not 'fail to invent HTML'. HTML is precisely
> what we were trying to PREVENT-- ever-breaking links, links going
> outward only, quotes you can't follow to their origins, no version
> management, no rights management."
I've been reading the ideas of Tim Berners-Lee, the man who can rightly be
said to have invented the web. The World Wide Web Consortium (W3C) he
founded is now promoting XML as a lingua franca for the web. Lee sees
XML as a way to promote automated web reading, so that web pages can
present data in machine-readable XML which is automatically translated
to nice looking HTML for humans. The result will be that both humans
and their software agents can browse the web with ease. Lee calls this
the "Semantic Web" and describes it as an important part of his initial
vision of what the web could become.
Associated with XML is the linking spec, XLink, which lets you set up
hyperlinks between XML documents. This is intended to address many of
the deficiencies with HTML linking. The XLink Design Principles have
a number of interesting points. Some excerpts:
1.1 XLink Shall Be Straightforwardly Usable Over the Internet
It is a requirement to allow for "open systems" of linking where
not all resources are under the control of a single person or
organization (along with easier "closed systems"). For example,
broken links must be tolerated.
Both unidirectional links (common on the Web today) and
multidirectional links (commonly used in commercial hypermedia
systems) must be supported.
1.2 XLink Shall Be Usable by a Wide Variety of Link Usage Domains
and of Classes of Linking Application Software
XLink should not favor particular domains over others. For example,
it should be usable in scholarly annotation, cross-referencing in
technical publications, and other domains of link usage.
1.3 The XLink Expression Language Shall Be XML
1.4 The XLink Design Shall Be Prepared Quickly
1.5 The XLink Design Shall Be Formal and Concise
1.6 XLinks Shall Be Human-Readable
1.7 XLinks May Reside Outside the Documents in Which the Participating
Resources Reside
It is a requirement that XLink provide a means to do sophisticated
out-of-line linking, in order for it to offer scalability and relief
from HTML linking problems. This does not mean that all links must
be out-of-line; on the contrary, the "Straightforwardly Usable Over
the Internet" principle demands that simple in-line linking also
be accounted for.
1.8 XLink Shall Represent the Abstract Structure and Significance
of Links
1.9 XLink Must Be Feasible to Implement
It is a nongoal for XLink to be easy to implement because we
recognize that certain functionality, in particular out-of-line link
handling with extended document groups, is inherently difficult. Our
goal is to make implementation at least tractable; that is, we must
consider implementability in our deliberations.
For more information on these new technologies, see www.w3.org. I have
found the tutorials at www.xml.com to be useful as well.
Hal
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