[Libxmlplusplus-general] Multiple Node types

[murrayc t-online de (Murray Cumming)]

On Mon, 2002-12-09 at 20:56, Christophe de Vienne wrote:
> I'm thinking of doing a base Node class, from which will herit ElementNode, 
> CommentNode, TextNode, and the 4 other possible node types.

Yes, that's what other parsers do, though it will require tedious use of
dynamic_cast<> or get_node_type().

> For the get_content and set_content accessors, I have 2 alternatives :

It's not clear where these 2 alternatives begin and end in this
paragraph:

> 	- put them in the Node base class, and implement it differently in TextNode / 
> CommentNode (here the meaning is obvious) and in ElementNode (here they would 
> set/get the content of a child TextNode, and eventually create one if it 
> doesn't exists).

That sounds fine. It would allow generic examination of nodes, with
convenience functions for common uses.

>  It is the behavior of libxml (see xmlNodeSetContent 
> implementation in tree.c).
> 	- put them only in TextNode and CommentNode.
> 
> The first one give the possibility to manipulate Nodes with content without 
> having to know about the TextNodes in a basic utilisation.
> The second one avoid the possible mistakes because of mixing the different 
> accessor behavior...
> 
> A third one would be to do the second one, plus adding another accessor on 
> ElementNode with a different name. But which one ?

I'm not sure what you mean here.

> 
> I think I prefer the first solution, with a good documentation. For now...
> I'm going to have a closer look to Xerces before making a decision.
> 
> Any comment/advise is welcome !
> 
> > I noticed that get_content() doesn't seem to work.
> 
> ? well in the current CVS version, the dom_parser example shows me some 
> contents. What did you mean exactly ?

I think the dom_parser shows comment nodes, not comments from
get_contents(). If get_contents() returned the child text node's data
then it might work. I could be wrong about this analysis - I haven't
looked in detail, and my problem is in a separate app.

-- 
Murray Cumming
murray usa net
www.murrayc.com