SGML: Grove and Grove Plan

Subject: Re: Mainstream SGML (was: Re: Tim Berners-Lee on the SGML origins of HTML from IEEE Computer)

Date: Fri, 01 Nov 1996 02:17:20 GMT

From: Charles@SGMLsource.com (Charles F. Goldfarb)

Newsgroup: comp.text.sgml


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On Thu, 31 Oct 1996 10:30:57 -0800, Lee Althen <lalthen@erinet.com> wrote:

>Sorry to be so unaware, but just what is a "grove plan"?

This answer is informal; the formal stuff can be found in the DSSSL standard and
the forthcoming HyTime TC. It's also compressed, so read it slowly.

A parsed SGML document is usually called a tree. Actually, it can be a
collection of trees because the value of an attribute, for example, can be a
tree and that tree isn't a "child" of the element. The DSSSL, HyTime, and SGML97
standards call that collection a "grove". 

The set of things that a notation such as SGML can represent is called its
"property set". The property set governs the construction of the grove when an
object conforming to the notation is parsed. A grove that includes every object
class and property defined in the property set is called a "complete grove." For
SGML, that would not only include the abstract information (the ESIS), but also
information about the original markup.

Since not every application will need to deal with a complete grove, a "grove
plan" can be specified that will limit the object classes and properties that
will appear in the grove. For example, you could choose to include comments and
PIs in an SGML grove plan, or you could omit them. It is possible for user or
vendor groups to define useful grove plans for interworking. (ESIS would be an
example of such a grove plan.)
--
Charles F. Goldfarb * Information Management Consulting * +1(408)867-5553
           13075 Paramount Drive * Saratoga CA 95070 * USA
  International Standards Editor * ISO 8879 SGML * ISO/IEC 10744 HyTime
 Prentice-Hall Series Editor * CFG Series on Open Information Management
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