[R] Documentation for library() and how to specify missing arguments

[Jeffrey J. Hallman]

Gabor Grothendieck <ggrothendieck at gmail.com> writes:
> Try this:
>
>> mx <- formals(identity)$x
>> missing(mx)
> [1] TRUE
>> sin(mx)
> Error in sin(mx) : 'mx' is missing

Neat. There's no way to look at 'mx' because calling any function
with it as an argument gives that same error message, including the auto
print function. What exactly is 'mx' here?

-- 
Jeff