[Rd] Help for methods

[hadley wickham]

> > Well, I know that, and you know that, but how is anyone supposed to
> > figure it out?  It means that you need to have a working knowledge of
> > the S3 and S4 class systems before you can use the help to reliably
> > get the documentation you need.
>
> For S3 you do to understand that there are different methods, and it
> is in `An Introduction to R'.  And ?summary reminds you.

But you also have to be able to identify if it is a S3 function or an
S4 method (or an ordinary function).

The reason I find this so much of a problem is that when you are
teaching R, one of the first things you want to do is teach your
students how to use help.  However, you can't teach them to use it
effectively until they know an awful lot about how the call semantics
of R.

Hadley