Re: [unrev-II] XML limits

From: Eric Armstrong (
Date: Mon Apr 03 2000 - 21:15:17 PDT

  • Next message: Doug Engelbart - Bootstrap Institute : "[unrev-II] Interesting IC explicitly developing an UNREV-type DKR"

    Paul Fernhout wrote:
    > Eric Armstrong wrote:
    > > I'm interesting if *any* encoding system would solve the problems
    > > you mention.
    > No XML-ish scheme can....
    Ignoring XML and anything remotely like it. What would you use?

    > ...
    > The point is to create a DKR/OHS flexible enough to deal with this
    > issue of representations changing over time as users needs change.

    > And to take things further, why invent XML when one could instead just
    > use LISP to the same effect (and with less bytes)? Lisp is used all
    > the
    > time to define representations such as:
    > (user
    > (ID 100001)
    > (name "Grampa Muenster")
    > (address "13 Mockingbird Lane"))
    If we're only talking about data representations, this could easily
    be done in XML. One is not required to use DTD-validation when parsing
    an XML structure. So one can easily add other name/value pairs, without
    being constrained by a DTD. The only time a DTD comes into play is when
    you *want* to enforce restrictions. And there are times when you want

    > Lisp can easily parse this which defines a valid LISP list, and we can
    > define LISP programs with related data that validate such
    > representations. That is what AI programmers have been doing for
    > decades.
    Certainly. Validating the structure is always possible in the program,
    with Lisp, XML, or any other data representation. DTD-validation is only
    a convience that permits taking that burden off the programmer, when it
    is desirable. There is also an intermediate ground. An DTD can be
    written so that any number of pairs of name and value elements can
    occur, so what you see is
    <name>ID</name><value>100001</value><name>address</name>... etc.
    The DTD can then ensure that the name/value pair restriction is never
    violated, but the values can be anything we want. Again, validation is
    not required, so even this restriction does not have to be enforced.

    > However, in my opinion, the investment in learning and
    > using these other systems (Smalltalk, Lisp) is worth it.
    No argument there. Maybe some of the flexibility you desire comes from
    the ease of manipulation in those languages, rather than from the data
    structures themselves?

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