Hadley Wickham

You only need to know that attributes are pairlists when working with them in C, so I'd rather remove the backlink that try and explain here.

Sure, a PR would be great

Why not just do this? ```R assert_that( any(c(1,2,3,4,5)

I don't understand why you are making this sort of assertion at all, let alone so many of them. Do you mind providing some additional context?

I'd recommend using the functions in fs

That's because `NA` is logical: cf. `NA_character_`, `NA_real_`, `NA_integer_`.

What about `is.flag(x, naok = FALSE)` ? Or `is.flag(x, nona = TRUE)`

Should also be parameters of the autoplot methods.

And `sign(x) * bc(abs(x), lambda)` ?

Or better the modulus transformation: `sign(x) * if (lambda == 0) log(abs(x) + 1) else ((abs(x) + 1)^lambda - 1)/lambda` (http://www.jstor.org/stable/2986305)