Re: IMRs again (was Re: Comments on the baboon plugin spec)

[sopwith redhat com (Elliot Lee)]

On Tue, 15 Sep 1998 20:29:19 +0100 (BST), Felix Bellaby
<felix@pooh.u-net.com> wrote: 

>Phil Dawes writes:
> > I still think that this functionality is part of corba though. All the
> > top corba vendors support shared library objects - the spec even
> > mentions them. 
> > 
> > If orbit is to support persistent objects activated transparently from
> > shared libraries then it must have a bootstrapping
> > activation/deactivation API embedded in the shared library. I believe
> > this is exactly what you have defined in the gnome-plugin specification.
>
>Phil is exactly right here. CORBA was designed to implement the OMG 
>object model. Hidden implementations are the sine qua non of object
>models. How can GNOME miss this point ?

Perhaps you miss the point... The Implementation Repository is not an
implementation, it is an object that has both an interface and an
implementation. I am merely suggesting that any IMR that is implemented
needs an interface to make it useful. Since the OMG has not deigned to
make any specific requirements at all of the implementation repository,
let alone give us .idl for it, it not worth the time to bother arguing
about what we think they intended by their one paragraph in the spec.

>The IMR will NEVER be specified by OMG because that would break the 
>object model itself!! The IMR is essential so that the ORB knows the 
>implementations it is hiding from the object clients!!

The two are not at all exclusive, and are in fact contradictory. If the
IMR is so essential, why will it never be specified, and why hasn't it
already been specified?

>One advantage of plug-ins defined as CORBA objects is the language
>independence of IDL. Put together a means of accessing IDL dynamically 
>from guile and every user can use every plug-in from within every
>gnome app without the app programmer knowing anything about it. Put 
>together a decent IMR and the user does not even have to install the 
>plug-in: the ORB can fetch it when it is needed.

And how do you expect the ORB to find out about this plugin, by using
dowsing rods on your filesystem? Until the OMG gives everyone an imr.idl
file, that's about the best way to do it.

>The visiblity of implementations has left us with huge collections of
>modules for all our interpreted languages (python, perl, etc.). Hide
>the implementations behind the ORB and you only need one module:
>the module to access IDL!!

This doesn't have anything to do with the IMR. You are confusing the word
"implementation" in "Implementation Repository" with clients having the
ability to manipulate the details of an object implementation.  The latter
is not what was being referred to at all.

-- Elliot "relevant signatures rule" Lee
Progress (n.): The process through which Usenet has evolved from smart
people in front of dumb terminals to dumb people in front of smart
terminals.  -- obs@burnout.demon.co.uk