- From: Tim Bray <tbray@textuality.com>
- Date: Sun, 15 Dec 2002 18:42:19 -0800
- To: Norman Walsh <Norman.Walsh@Sun.COM>
- Cc: www-tag@w3.org
Norman Walsh wrote: > I would wager that almost every significant document that I've ever > written has included at least a few entities. By my crude grep|wc -l > estimate, there are more than 2800 entity declarations (transitively) > in the internal subset of book.xml for "DocBook: The Definitive > Guide". I think we'll be talking about this Monday. Granted that significant publication-oriented XML apps, particularly with an SGML heritage, make heavy use of entities. Let's ignore the issue of parameter entities because they are a necessary function but are isolated off in the DTD not in the instance. I think that the use of entities has worked reasonably well for the cases where they're simple macros of zero arguments. I think it has fallen down miserably whenever you've tried to use them for their ostensible purpose (cf the SGML Handbook) as some sort of storage/content management infrastructure; to start with the ID/IDREFs break instantly. > There are ten or fifteen in the sources for most W3C specs that I've > seen. For (a) naming odd characters and (b) simple boilerplate. Hardly showstoppers. > It might be useful to have a standard for "Prescriptive Standalone > XML" that people could point at in those applications where such a > prescription is necessary, but removing entities from XML in general > is just not something I'm willing to consider. Nothing we can do will take entities out of XML 1.* at this point in time. I've proposed XML-SW which has no entities or DTD at all (but does have a DOCTYPE declaration so you can use XML 1.* validation on it just fine). There are various intermediate points you could think of, such as: (a) entities, internal only (b) (a) + internal subset only (c) (b) + no recursion (d) (c) + replacement text has to be shorter than name (e) (b) + names for character references only I do think we can agree that no existing or proposed schema effort is apt to re-invent the entity mechanism, so I could be persuaded that in something like XML-SW, we could live with one of (a) through (e) or a variation. As for the DTD's other role, sticking something right in the document that lets it point at the schema that it claims you ought to validate with, I have no patience with that at all any more, for a variety of reasons. -Tim
Received on Sunday, 15 December 2002 21:42:20 UTC