Re: SVG12: DOMObject portability

Hi Boris,
I'm just replying to your last question since I don't know anything
about Gecko. The reason not to return a Node is because you can set
focus on an SVGElementInstance (like a use:d element) which isn't a Node
but an EventTarget.
/ola
 
From: Boris Zbarsky <bzbarsky@mit.edu
<mailto:bzbarsky@mit.edu?Subject=Re:%20SVG12:%20DOMObject%20portability&
In-Reply-To=%3C435E4623.101@mit.edu%3E&References=%3C435E4623.101@mit.ed
u%3E> > 
Date: Tue, 25 Oct 2005 09:50:11 -0500
Message-ID: <435E4623.101@mit.edu> 
To: Andrew Shellshear <Andrew.Shellshear@cisra.canon.com.au
<mailto:Andrew.Shellshear@cisra.canon.com.au?Subject=Re:%20SVG12:%20DOMO
bject%20portability&In-Reply-To=%3C435E4623.101@mit.edu%3E&References=%3
C435E4623.101@mit.edu%3E> > 
CC: www-svg@w3.org
<mailto:www-svg@w3.org?Subject=Re:%20SVG12:%20DOMObject%20portability&In
-Reply-To=%3C435E4623.101@mit.edu%3E&References=%3C435E4623.101@mit.edu%
3E> , SVG WG <w3c-svg-wg@w3.org
<mailto:w3c-svg-wg@w3.org?Subject=Re:%20SVG12:%20DOMObject%20portability
&In-Reply-To=%3C435E4623.101@mit.edu%3E&References=%3C435E4623.101@mit.e
du%3E> > 
 
Andrew Shellshear wrote:
> We have added the following explanitary text to the description of 
> getCurrentFocusedObject in
>
http://www.w3.org/TR/2005/WD-SVGMobile12-20050413/svgudom.html#svg::SVGS
VGElement 
> -
> 
> Returns a reference to the object which has the focus.  This returns a

> DOMObject because the currently focused object may be an object
outside 
> the SVG namespace.  If the currently focused object is in the SVG 
> namespace, it should be cast to events::EventTarget.
 
I'm trying to figure out how this would work in a strongly typed
language (C++, 
say).  Who's doing the casting?
 
For example, the C++ binding in Gecko for the IDL involved would look
like 
(unrolling some typedefs):
 
   int GetCurrentFocusedObject(ISupports **);
 
Now how is the suggested explanatory text supposed to be implemented in
this 
situation, exactly?
 
Is there a reason not to just return a Node to start with?  Then the
caller 
could actually check for the SVG namespace and cast to
events::EventTarget or 
EventTarget or whatever is appropriate as needed.  Or are there cases
when the 
"focused object" is not a Node?  If so, what does it mean for it to be
"in the 
SVG namespace"?
 
-Boris