[R] Making an S3 object act like a data.frame

[hadley wickham]

> If your class is a subclass of data.frame then I think
> it ought to be a special sort of data frame so all you
> need to do is the following in which case you get subscripting
> for free by inheritance:

My class is actually an external pointer to a data set stored in
ggobi, so I don't think this will work.  as.data.frame.ggobiDataset
retrieves the whole dataset out of ggobi and in to R.

Hadley