xml-dev - Re: On edge-labelled graphs in XML

[tpassin@home.com]

Wayne Steele asked -

> Why would someone prefer an edge-based model to a node-based one?
> or vice-versa?
>
> IMHO, the concepts of a "node" and a "tree" seem pretty straightforward;
> dealing with edge-based abstractions is about as comfortable as reading a
> book turned upside-down.

Well, I'm definitely no expert on this.  What I've seen so far is that a
node gives you a place to have branches.  That is, an edge comes in and many
edges can go out.  Also, a node seems like a good place to hold a value.  If
you like to make a distinction between a (abstract?) thing and its value,
then an edge can the the thing and the node can hold its value.  Now if you
were to say that a set or list of elements could also be the value of the
thing, it would make even more sense that a node is for holding a value.

This is a little different from simply reversing nodes and edges, because in
a normal graph, edges can only branch at nodes, not in the middle of an
edge.

When I did the playing around I mentioned in my previous post, I got the
impression that using an edge-labeled graph was very simple and clean.  I
can't make any other claims because I don't know enough about it.

Cheers,

Tom Passin