use meta syntax in DTD

I think the DTD (section 5.2) for the where operators would be clearer if
it were expressed using a "meta" syntax.  Note that I am not calling for
any change in the actual DTD, but only in how we describe it.

The text would read as follows 

 5.2. The DAV:simplesearch DTD

In the DTD below, the string EXPR is to be understood as a notational
shorthand for
  (and | or | not |
   eq | lt | gt | lte | gte | 
   isnull | like | contentpassthrough)

We use this abbreviation to make the DTD easier to explain.  In the actual
DTD, EXPR does not occur.

...

<!ELEMENT where          EXPR >

<!ELEMENT and            EXPR + >
<!ELEMENT or             EXPR + >  
<!ELEMENT not            EXPR  >  

etc.

This makes the parallels among these elements much more easy to see.

Note also that the protocol draft did not allow "like" in "where", which I
assume was a typo.  The 'meta' syntax I propose would make that impossible.

I stress that this is only a notational covenience for the document, not
for the DTD.

Received on Monday, 14 September 1998 12:50:17 UTC