WebCGMNodeList

[Benoit Bezaire <benoit@itedo.com>]

Hi guys,

I'm unclear about something... that is, how are users going to use
WebCGMNodeList!? 

We have the following methods which return WebCGMNodeList:
  WebCGMNodeList WebCGMNode.childNodes;
  WebCGMNodeList WebCGMNode.attributes;
  WebCGMNodeList WebCGMNode.getElementsByTagNameNS()
  WebCGMNodeList WebCGMPicture.getAppsStructureByName()
  WebCGMNodeList WebCGMPicture.createWebCGMNodeList()

And the following which requires one as input:
                 WebCGMPicture.hightlight(in WebCGMNodeList)

The WebCGMNodeList interface is as follows:
interface WebCGMNodeList {
  readonly   attribute unsigned long count;
  WebCGMNode           item(in unsigned long index);
  WebCGMNode           removeItem ( in unsigned long index )
                                         raises( WebCGMException );
  WebCGMNode           appendItem ( in WebCGMNode newItem )
                                         raises( WebCGMException );
  void                 clear()
                                         raises( WebCGMException );
};

My concerns are related to a node list of APS nodes and a node list of
Attr nodes. It is pretty clear that 'count' and 'item' have value;
they are required to walk through a list of nodes regardless if they
are APS or Attr.

In a previous email, I said that there are technical reasons why
'clear' shouldn't be present. So that leaves 'removeItem' and
'appendItem' as questionable... Let's start with 'appendItem', it is
needed for adding WebCGMNodes to a list of objects to be highlighted.
But what happens if someone does:

WebCGMNode.childNodes.appendItem() // this adds a new child

I thought we wanted to forbid the 'addition' and 'deletion' of APS in
the DOM. If that is true, I don't see a use case for 'removeItem',
except maybe to remove an item from a node list which shouldn't be
highlighted.

'removeItem' and 'appendItem' on Attr node list also have some issues.
'removeItem' could be seen as an equivalent to removeAppStructureAttr,
and 'appendItem' as setAppStructureAttrList. The problem is that we
don't have a createAttrNode method to feed into appendItem. Should we
add such a method?

I'm not sure if people are following me, I may not be very clear. But
here's my proposal.

Proposal:
All methods returning a WebCGMNodeList, with the exception of
createWebCGMNodeList, must return 'readonly' node lists. With this
approach 'appendItem' and 'removeItem' can remain on the interface and
will only work for node lists aimed at being used with the highlight()
method.

Thoughts?

-- 
 Benoit                 mailto:benoit@itedo.com