[Rd] get ...

[Luke Tierney]

On Sat, 28 Jun 2008, Peter Dalgaard wrote:

> Gabor Grothendieck wrote:
>> Suppose we do this:
>>
>> 
>>> f <- function(...) environment()
>>> e <- f(a = 1, b = 2)
>>> ls(e, all = TRUE)
>>> 
>> [1] "..."
>> 
>>> e$...
>>> 
>> <...>
>> 
>>> class(e$...)
>>> 
>> [1] "..."
>> 
>> Is there any way of getting a and b given e without
>> modifying f?
>> 
>> evalq(list(...),e)
> $a
> [1] 1
>
> $b
> [1] 2
>
>

I'm wondering though whether we should allow the internal DOTSXP value
of "..." to escape to the user level.  Might be more appropriate for
get(e,"..."), e$... (and as.list.environment and maybe a few other
things) to give the "Error: '...' used in an incorrect context" error
if the value is a DOTSXP.

luke

-- 
Luke Tierney
Chair, Statistics and Actuarial Science
Ralph E. Wareham Professor of Mathematical Sciences
University of Iowa                  Phone:             319-335-3386
Department of Statistics and        Fax:               319-335-3017
    Actuarial Science
241 Schaeffer Hall                  email:      luke at stat.uiowa.edu
Iowa City, IA 52242                 WWW:  http://www.stat.uiowa.edu