Apps Messaging - Semantics of a Message

[Mike Fitzpatrick]

On 4/10/07, Mike Fitzpatrick <mjfitzpatrick at gmail.com> wrote:
> > I think I get the idea, but this is really rather strange.  We would
> > like to display an image (for example), so we broadcast a display
> > request to anyone who might be out there, and they all on their own
> > display the image, or do some other random thing which is similar?
>
> Of course it wouldn't be a random thing, we'd assume the developer
> would read the spec's definition of the 'display' class and do something
> along those lines in the context of his/her app.  But how is sending a
> display request to some anonymous process for handling that much
> different than IRAF using the image display without knowing specifically
> whether it's XImtool or DS9 on the other end.  Just as the only require-
> ment is an understanding of the IIS protocol, in the msg  system the
> only requirement is an understanding of a display.fits message (and
> implicit agreement that it does "the right thing").

Just to clarify:  The whole point of this is to reduce the chance that
Aladin, Mirage, DS9, XImtool, etc would all see fit to create their own
mtype specific to the app.  They can still do this of course, but if
display.whatever works for each of them the sender is free to use
any of them without change.

-Mike