> I think the most important point this paper states (and
> demonstrates) is:
>
> >human beings will find them [XSchemas] painful to write by
> hand, due to their great redundancy compared to DTDs.
>
> This conflicts directly with design goal 5, which states:
>
> >XSchema documents shall be easy to create, read, and
> modify, and shall
> provide authoring support.
The emphasis here should be on "by hand". Writing XML documents
of any sort without machine support is painful. XED, to take
the lowest common denominator, makes a big difference here.
> When I first looked at the idea of encoding DTDs in XML a
> couple of months ago, one of my motivations was that I find
> the current DTD syntax very ugly, and I came to the same
> conclusion: whatever the merits of an XML encoding, it would
> not be user-friendly. (My feelings about XSL are the same).
> XML works well as a markup language for text; it also works
> well as a markup language for data; but it is very poor as a
> human-readable lexical encoding of a language with rich
> syntax.
I agree, if for "readable" you substitute "writable". Proper
indentation conventions and other such things can make reading
easier. But then, syntax-coloring editors can make writing
easier, too.
> * we can imagine a "pre-parser" which takes an RXML document
> and automatically generates additional XML markup so that
> all the syntax is now fully accessible as elements and
> attributes. This pre-parsed document would no longer be
> easily readable, but it would be easily processable using
> standard XML tools
Actually, I think XML-DTD syntax is fine for the purpose.
Write DTDs, translate to XSchemas; that's what I did when writing
the draft itself to produce the Meta-XSchema.
> * We could encode both the current DTD information and the
> additional constraints in RXML
Unfortunately it's hard to know how far to go. There is
a trivial XML encoding of DTDs something like this:
<DTD><![CDATA] insert the DTD here ]]></DTD>
and there is a slippery slope of just how much to encode as
elements and attributes, and how much to leave in DTD format.
-- John Cowan http://www.ccil.org/~cowan cowan@ccil.org You tollerday donsk? N. You tolkatiff scowegian? Nn. You spigotty anglease? Nnn. You phonio saxo? Nnnn. Clear all so! 'Tis a Jute.... (Finnegans Wake 16.5)