RE: Issues with uDOM IDL and multiple inheritance


We have faced the same problem in Adobe SVG Viewer development. There are various ways to solve it, the easiest is to just skip doing custom COM interfaces and implement IDispatchEx directly. Normally you'd implement custom interfaces and implement IDispatchEx through the type library, but you don't have to do it this way. Scripting engine only uses IDispatchEx anyway. And I remember that there are subtle reasons (e.g. JavaScript "expando" implementation and parameter type conversions) why custom IDispatchEx is needed to be fully blend into JavaScript - so doing it through type library is suboptimal in any case.

Feel free to contact me directly if you have further questions in this area.


-----Original Message-----
From: [] On Behalf Of Alexander Adam
Sent: Sunday, November 26, 2006 4:17 PM
Subject: Issues with uDOM IDL and multiple inheritance


During the implementation of the Renesis SVG Player ( we've
discovered that the uDOM is making heavy use of multiple interface
inheritance. This is just fine for Java but for other languages and
implementations this is not possible. As an example, we're hooking into the
IE ActiveScript Engine for the new release to provide a HTML<>SVG
communication level and we cannot implement the uDOM IDL as it is proposed
due violating the Windows COM Rules (inherit from one interface only) so
this is giving us quite a hard time.

You might give some thoughts on this,

Alexander Adam
Geschäftsführer / CEO  
Phone: +49 (0) 9401 60570-0
Mobil: +49 (0) 170 3073827             
E- Mail:

Emia Systems           
Dorfstrasse 3
D-93083 Obertraubling

Received on Tuesday, 28 November 2006 15:41:47 UTC