[Rd] Putting an object in a data farme

[Duncan Murdoch]

I'd like to use the modelling functions, in particular  model.frame,
with the S4 orientation objects I'm writing.  However, these use
data.frames, and data.frames object to having my objects put in them.
model.frame checks the mode of the object before it puts it in;
data.frame seems to be trying to coerce my class to data.frame, and
it's failing.

What's necessary to put a nonstandard object into a data.frame?

Duncan Murdoch