Another look at namespaces

James Tauber jtauber at
Mon Sep 20 14:11:04 BST 1999

> This distinction, that the Document Type Definition is not the same as the
markup declarations, is as old as

SGML makes the distinction and I think it is a good one but I don't think
XML does. In XML a DTD is the (formal)grammar defined by the markup
declarations and no more.

In SGML, Document Type Definition = names + syntax + semantics
In XML, Document Type Definition = names + syntax

(NOTE: I'm separating names and syntax to emphasis the distinction between a
choice of name for an element type and a choice of syntactic contraint.
Arbitrariness of the linguistic sign and all that)

Perhaps we need a word for names + syntax + semantics in XML.

Some people use "XML vocabulary" for this and others use "XML vocabulary" to
mean a set of element and attribute names along with their semantics (ie
little or no syntax).

Whether one views:

    vocabulary = names + semantics
    vocabulary = names + syntax + semantics

possible determines their standing on the number of namespaces XHTML 1.0
should have.


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