[R] Checking for and adding "..." arguments to a function...

[Rui Barradas]

Hello,

Use ?formals.

 > formals(myfunction)
$a


$b


$c


$...


Hope this helps,

Rui Barradas

Em 17-02-2014 21:22, Jonathan Greenberg escreveu:
> R-helpers:
>
> I'm guessing this is an easy one for some of you, but I'm a bit
> stumped.  Given some arbitrary function (doesn't matter what it does):
>
> myfunction <- function(a,b,c)
> {
> return(a+b+c)
> }
>
> I want to test this function for the presence of the ellipses ("...")
> and, if they are missing, create a new function that has them:
>
> myfunction <- function(a,b,c,...)
> {
> return(a+b+c)
> }
>
> So, 1) how do I test for whether a function has an ellipses argument
> and, 2) how do I "append" the ellipses to the argument list if they do
> exist?
>
> Note that the test/modification should be done without invoking the
> function, e.g. I'm not asking how to test for this WITHIN the
> function, I'm asking how to test "myfunction" directly as an R object.
>
> Thanks!
>
> --j
>
>