- From: Thomas B. Passin <tpassin@home.com>
- Date: Tue, 16 Oct 2001 00:13:41 -0400
- To: <www-rdf-interest@w3.org>
[Peter F. Patel-Schneider] > Edge-labelled models cannot handle things like > > <foo> > 7 > <bar>5</bar> > </foo> > > which are allowed in XML. > You can make a perfectly good edge-labeled graph from arbitrary XML, even with mixed content. Just imagine that all continuous fragments of character content are wrapped in imaginary <text> elements. Each element name maps to an edge label. Child element order maps to clockwise (or counter-clockwise) placement of the edges. Node are unlabeled and have no content except for leaves at the end of "text" branches, which contain the corresponding character data. Thus all nodes are anonymous. A document starts with an implied (anonymous) root node. You may object that having all the nodes anonymous is pretty strange for RDF. I reply that for arbitrary XML, you do not know what the element names and so forth "mean", so you can't very well apply RDF-like assignments to them. Now obviously you can start adding specialized rules if you want to map certain structures differently. For example, you could give special treatment to xlink arcs and to elements in the rdf: namespace. I'm just pointing out that xml does map very nicely to edge-labeled graphs even though it is never presented this way in books and courses. The edge-labeled approach is a dual for the node-labeled (DOM) approach. The node-labeled approach gives you unlabeled edges, the edge-labeled approach gives you unlabeled nodes. RDF gives you labels for both edges and nodes, but only because of a set of conventions as to how to interpret certain xml structures. Cheers, Tom P
Received on Tuesday, 16 October 2001 00:08:33 UTC