predicting function calls?

[Mike Meyer]

roy at panix.com (Roy Smith) writes:
> Objects can have attributes (data) and operations associated with
> them.  It would be very convenient to use the "." syntax to access
> both of these, i.e. be able to say:
>
> print handle.someAttribute
> print handle.someOperation (arg1, arg2)
>
> I'm using __getattr__() to process both of these constructs, and
> herein lies the rub; I need to do different things depending on
> whether the name is an attribute or an operation.  I can ask the DB
> for a list of the names of all the operations supported by a given
> object, but that's a fairly expensive thing to do, so I'd rather avoid
> it if possible.  It would be really nice if I had some way to find
> out, from inside __getattr__(), if the value I'm about to return will
> get called as a function (i.e., the name is followed by an open
> paren).  I can't see any way to do that, but maybe I'm missing
> something?
>
> Any ideas?

Fnorb (a pure-Python CORBA orb) dealt with this by not allowing
attributes per se. Instead, it provided _get_AttributeName and
_set_AttributeName as appropriate for each attribute in the IDL. Doing
this means that *everything* you hand back from __getattr__ is going
to be a callable, and presumably called at some point.

Properties postdate Fnorb, so weren't considered in it's design. You
might be able to do something with them as well.

      <mike
-- 
Mike Meyer <mwm at mired.org>			http://www.mired.org/home/mwm/
Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information.