* Aryeh Gregor Simetrical+wikilist@gmail.com [Sun, 25 Apr 2010 20:46:14 -0400]:
In XML, named entity references like and • (with the special exceptions of < > & " ') can be treated as well-formedness errors across the board by conformant XML processors. (Yes, this means that *any* XML document that uses *any* named entity reference except the special five is not well-formed, if you ask these XML processors.) Alternatively, if a DTD is provided, conformant XML processors can retrieve the DTD, parse it, and treat the reference as a well-formedness error if it doesn't occur in the DTD, otherwise parse it as you'd expect. (Yes, processors can really pick whichever behavior they want, as far as I understand it. As we all know, the great thing about standards is how many there are to choose from.)
Wouldn't it be enough just to define an entity? http://www.criticism.com/dita/dtd2.html#section-ENTITIES I used such definition for nbsp once in XSL sheet. Don't know how well it works alone in XML. Dmitriy