http://norman.walsh.name/2005/11/05/dbtiny 8 142 2005-11-05T16:19:31-05:00 $Date: 2005-11-05 16:56:05 -0500 (Sat, 05 Nov 2005) $ Norman Walsh 2005 Norman Walsh Want DocBook with just five elements? You got it. RELAX NG lends itself to more modular schema designs than DTDs ever did. The DocBook V5.0 grammar is built from modules and it would be fairly easy to construct a new top-level driver file that didn't include some modules. For example, if you didn't want msgset, you could just leave out msgset.rnc. But an even simpler answer occurred to me the other day. It's a little bit “brute force”, but that's ok. Construct a grammar that includes the base grammar, sets the start, and sets to notAllowed all the elements you want to exclude: include "http://docbook.org/xml/5.0b1/rng/docbook.rnc" { start = db.book|db.chapter|db.article db.abbrev = notAllowed db.abstract = notAllowed db.accel = notAllowed db.ackno = notAllowed … } That's DocBook with just five elements. Want to allow emphasis? Just delete the line that makes it not allowed. You can add any other elements the same way until you have just the DocBook you always wanted. Any document that's valid according to your “tiny” grammar will also be valid according to full DocBook. The only thing you have to watch out for is constructing a grammar that won't validate any document at all. For example, if you allowed book but not title, you could never validate a book because a title is required.