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Re: [Element Traversal LC] access to element by index

From: Henri Sivonen <hsivonen@iki.fi>
Date: Wed, 2 Apr 2008 12:27:43 +0300
Cc: "Web APIs WG (public)" <public-webapi@w3.org>
Message-Id: <2E7EC933-909E-4F6A-88C1-3EB7907DA5AD@iki.fi>
To: Boris Zbarsky <bzbarsky@mit.edu>

On Apr 2, 2008, at 00:48, Boris Zbarsky wrote:
> OK.  So item() would be available on Element after casting it to  
> NodeList in those implementations.  I guess you're saying that the  
> cast would not longer be unambiguous if there were multiple  
> NodeLists that might make sense?  So childElements couldn't be  
> implemented with a |return this;|?
>
> That doesn't seem like such a terrible implementation burden to me,  
> to be honest...


I'm not claiming it would be awfully hard, but it does change the  
impact of Element Traversal from adding four or five methods on an  
existing class (mere code footprint; super-simple) to adding more run- 
time object instances. And then, there are issues like should  
childElements return the same object every time. And if yes, then the  
implementor needs to add a new pointer to each element node or to add  
a hashtable on the owner document or something along those lines.  
Again, not awfully hard, but still more complex than just adding  
convenience methods on an existing class. And to what end? To use  
indexing instead of list-style iteration.

-- 
Henri Sivonen
hsivonen@iki.fi
http://hsivonen.iki.fi/
Received on Wednesday, 2 April 2008 09:28:30 GMT

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