Re: XML and GNOME community

[Tom Tromey <tromey cygnus com>]

Andrew> Well, drag-and-drop and communication with the panel could be
Andrew> implemented by sending chunks of XML back and forth, instead
Andrew> of using CORBA.

DnD probably should use some X-based mechanism.  I don't have a really
deep reason; it just feels right.

Andrew> I can't think of any really strong arguments either way,
Andrew> assuming that ORBit actually gets implemented.

My experience has been this:

* Specifying interfaces solely in terms of protocols leads to
  incorrect implementations, and interoperability problems.
  (E.g., there are lots of programs that think they speak HTTP,
  whereas they actually speak some broken variant.)

* Using extremely free-format protocols leads to long term maintenance
  problems.  (In my case the problem involved programs communicating
  by sending Tcl messages around.  After a few years, it became hard
  for new programmers on the project to get a good feeling for what
  was going on.)

* Specifying APIs and hiding the protocol seems to work fairly well.
  Using an API gives you plenty of flexibility when you need it (you
  can always just use string arguments, or alists, or whatever), but
  also allows tighter specification.  Hiding the protocol means it can
  be implemented more carefully, by experts.

So in my view there are strong reasons to prefer CORBA over something
less structured.

Last, CORBA is likely to have much better performance than sending XML
around.  That's because, for compiled languages, the CORBA stubs can
be optimized to marshall and unmarshall arguments in a more
intelligent way.

Tom