DOM node are 'live'

[Benoit Bezaire <benoit@itedo.com>]

Hi,

  I'm not sure if other implementers dealt with this issue already,
  but we recently did, and the spec should really be clarified. The
  issue has to do with the nodes being 'live' or not. The DOM level 3
  specification clearly specifies that DOM nodes are live:

  "The DOM also specifies a NodeList interface to handle ordered lists
  of Nodes, such as the children of a Node, or the elements returned
  by the Element.getElementsByTagNameNS(namespaceURI, localName)
  method, and also a NamedNodeMap interface to handle unordered sets
  of nodes referenced by their name attribute, such as the attributes
  of an Element. NodeList and NamedNodeMap objects in the DOM are
  live; that is, changes to the underlying document structure are
  reflected in all relevant NodeList and NamedNodeMap objects. For
  example, if a DOM user gets a NodeList object containing the
  children of an Element, then subsequently adds more children to that
  element (or removes children, or modifies them), those changes are
  automatically reflected in the NodeList, without further action on
  the user's part. Likewise, changes to a Node in the tree are
  reflected in all references to that Node in NodeList and
  NamedNodeMap objects."

  The wording in our specification is not that clear, but I think it
  should be.

  On a related matter... I earlier proposed that WebCGMStringList be
  added a clear() method and that WebCGMNodeList have the same. Based
  on implementation feedback, I made a mistake.  Sorry.  It is fine for
  WebCGMStringList to have a clear() method, but not for
  WebCGMNodeList. Instead, the removeItem method should be used to
  clear a node list.  Here's why:

  var aps = cgmPic.getAppStructureById("_1"); // returns an APS
  var a   = aps1.attributes; // returns a node list
  var i   = a.item(0); // return a attr node
  a.clear(); // a is empty and aps1 doesn't have any attributes
  // what's the state of i?
  
  The method removeItem returns the deleted node, so it is still
  accessible: WebCGMNode removeItem ( in unsigned long index ). The
  same is not applicable for clear().
  
  WebCGMStringLists do not contain interface pointers and are
  therefore not live, the problem is not existent in this case.

  Thoughts?

  I'm willing to take one action item:
  1) To propose wording with regards to DOM nodes being live.

  Could Lofton take one:
  2) To remove the clear() method on WebCGMNodeList.

-- 
 Benoit                 mailto:benoit@itedo.com