- From: <keshlam@us.ibm.com>
- Date: Mon, 28 Feb 2000 18:25:49 -0500
- To: David Brownell <david-b@pacbell.net>
- cc: Thomas Ashe <Thomas.Ashe@Blackbaud.com>, www-dom@w3.org
>> Given two nodes of a common parent, identify which node precedes the other >> in the parent's ChildNodes nodelist. >> Is there such a creature in the current specs? > >You'd basically look at the nodelist yourself. Takes a few lines >of code -- would you seriously expect DOM to save you the work of >writing such a simple subroutine? If so, why? I've heard one strong case where an ordering query would be useful -- not on NodeLists, but on lists of nodes generated in other ways. That case is XSLT. It's not uncommon there to want to take the union of several seperately executed searches and present it as a single list of nodes, in document order. In that situation, convolving the lists to interleave them correctly can be a significantly expensive operation. We've had periodic requests from XSLT developers to add a Node.isBefore(Node) operation, which they could invoke in the hope that a specific DOM might have an underlying representation which permits optimizing this operation. Given that some models _can_ answer this question much more quickly via their internal representations than via their DOM API, I think it's worth considering. Statement of bias: I wrote one such model; that fast-ordering feature is one of several reasons LotusXSL/Xalan prefers to read the input document from DTM rather than from a "normal" DOM. ______________________________________ Joe Kesselman / IBM Research
Received on Monday, 28 February 2000 18:30:46 UTC