[Rd] buglet in is.na?

[Nicholas Lewin-Koh]

Hi
the following example I think demonstrates the inconsistency
> f<-function(x) x
> length(f)
[1] 1
> is.na(f)
[1] FALSE
Warning message:
In is.na(f) : is.na() applied to non-(list or vector) of type 'closure'

The documentation states:
Arguments
x       an R object to be tested.
value   a suitable index vector for use with x.

And nowhere in the details was it implied (to me anyway) that x could
not be a function
or anything else in R for that matter. Did I miss something?

Nicholas