On 13/05/06, Anne van Kesteren <ann...@opera.com> wrote:

Not quite. NodeList are, in some ways, array-like. But StaticNodeList is more array-like, for several reasons:

- First of all, I think StaticNodeList would be implemented as an actual list or hash table, not as filters used on the live node tree. This specifically because it's not supposed to be affected by changes in the node tree. This means they are considerably different under the hood.

- Second, manipulating the DOM using elements gotten from looping through a NodeList will have effects on that NodeList during the loop. Removals, reparentings, insertions etc, may affect the NodeList. StaticNodeList will not be affected by changes to the DOM. This means the different mapping functions may have very bizzarre side effects on NodeLists that they would not have on StaticNodeLists.

- Third, NodeLists being live means you cannot manually manipulate them. StaticNodeLists don't have this problem. Since they are not live, manipulation of them should not be a problem. This means array functionality such as sort, push, pop that would simply not make sense on a NodeList would make perfect sense on a StaticNodeList.

I do see two notable differences between StaticNodeList and ECMAScript Array though:

- NodeList is naturally dense, so StaticNodeList would have to force denseness too. Array is sparse. This means that what happens when the user tries assigning to random indices larger than the length; or removing elements in the middle of the StaticNodeList; or setting the length to a value larger than the current length; would need to be defined in a way that makes sense in the ECMAScript bindings.

- NodeLists only contain Node objects, so the same would have to be true for StaticNodeList. Arrays may contain any type of JavaScript object. This means what happens if the user tries to add a non-Node object to the StaticNodeList would have to be defined in the ECMAScript bindings.

One possible solution to these problems: - If trying to insert a non-Node in the StaticNodeList, throw the appropriate RunTime error. - If trying to delete any index smaller than the length of the StaticNodeList, throw the appropriate RunTime error. (might have to be length-1, to allow for removing the last element in StaticNodeList) - If trying to assign to an index larger than the length of the StaticNodeList, thow the appropriate RunTime arror. - If trying to assign a value larger than the current length of the StaticNodeList to the length property, throw the appropriate RunTime error. -- David "liorean" Andersson <uri:http://liorean.web-graphics.com/>