[Rd] Help for methods

[hadley wickham]

> In the alpha of 2.4.0, both suggestions above work, as do ?summary and
> ?summary(data.frame()).  ?summary(lm()) gives the same man page, rather
> than the summary.lm page (but the page does have a link to that page).

That's great.

The fact that summary includes a link to summary.lm is relevant for
this specific example, but not in general.

This is also related to my distaste for having multiple methods
documented in one function.  As a developer of R packages, I
understand why people do it (and do it myself), but as a user of help,
it makes the documentation harder to read.

> The problem with S3 methods is that it's pretty difficult for R to know
> that a particular object is an S3 generic.  The only sign is that it has
> a call to UseMethod() in it.  I think this is one of the motivations for S4.

Well, it is even more difficult for a human to know!

Hadley