RE: ESIS, Groves and XML

["Frank A. Christoph" <christo@xxxxxxxxxxxxxxxxxx>]

I think this is essentially correct. I don't know about the OO methodology
stuff.

Daniel Mahler wrote:
> 1 A grove is a lableled directed graph.
>   There a specified subgraph, which is a tree.
>   This is the parse tree of the document.
>   Remaining arcs are put in by subsequent processing.

Actually, it is a multigraph, not just a graph.

I don't think it is accurate to relate the notion of parse tree with trees
in the grove.

> 2 The arcs are called attributes.
>   However, there are also attributes which are not arcs,
>   that specify scalar values for a node.
>   This is vaguely similar to entity-relation modelling
>
> 3 A property set specifies a set node and attribute kinds that go with
> them.
>   Basically this is a schema for labelled graphs.
>   It plays the role of an ER model.
>   (It can be thought of as a DTD for a class of graphs.
>    Although a single property set specifies the class of groves for many
> DTDs)
>
> 4 There is a property set, the SGML property set, to which all groves
>   of SGML documents conform, regardless of the documents DTD.
>   One can specify property sets for groves that are not derved from SGML
> documents.
>   (There are extremely few of these. :) )
>
> 5 A grove plan is a subset of a given property set
>   (ie it specifies a subset of node and attribute kinds)
>   Given a grove conforming to the property set,
>   the grove plan specifies a subgraph, or 'view', of the grove
> consisting
>   only of the nodes and attributes of kinds included in the grove plan.

Yes. Strictly speaking, though, a plan is more than a set, since there is a
partial order on them expressing dependencies between the subsets.

> 6 ESIS is (or correponds to?) a grove plan,
>   which retains approximately as much information
>   as is available through DOM or SAX

ESIS is not a grove plan. It is not a formal thing, just a notion. But is
approximately corresponds to a particular grove plan, yes.

I don't know if the level of information is comparable or not, although I
suspect it is.

> 7 An ESIS stream is a machine oriented data format for serialising the
> ESIS view
>   of a grove. I am not sure if this is a part of the spec or something
> Jade/SP specific.

It is SP-specific. It really has no formal relation to ESIS. I usually just
think of it as "SP's output format."

-- FC


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