[R] ellipsis-related error: used in an incorrect context, no ... to look in

[Felix Andrews]

The problem is related to the processing of the 'groups' argument,
which is subject to non-standard evaluation. The groups argument is
substitute()d and evaluated in a special context ('data' etc). But
this gets messed up if you are not passing the symbol directly. The
work-around is to rewrite the call inside f.barchart (as is done in,
for example, lattice:::barchart.formula)

Example:

f.barchart <- function(...) {
    ccall <- match.call()
    ccall[[1]] <- quote(barchart)
    ccall$panel <- function(x, y, ...) {
               panel.barchart(x, y, ...)
           }
    eval.parent(ccall)
}

   x <- data.frame(a = c(1,1,2,2), b = c(1,2,3,4), c = c(1,2,2,1))
   f.barchart(a ~ b, data = x, groups = c)

It is also good practice to update the $call component of the trellis
object to reflect your high-level function:

    ans <- eval.parent(ccall)
    ans$call <- match.call()
    ans



On 19 February 2010 19:58, lith <minilith at gmail.com> wrote:
> Does nobody have an advice concerning that problem? If it is a FAQ,
> I'd appreciate a pointer to a discussion of this issue. With the docs
> accessible to me, I wasn't able to solve that problem.
>
>>     require(lattice)
>>     f.barchart <- function(...) {
>>         barchart(...,
>>             panel = function(x, y, ...) {
>>                 panel.barchart(x, y, ...)
>>             }
>>         )
>>     }
>>
>>     x <- data.frame(a = c(1,1,2,2), b = c(1,2,3,4), c = c(1,2,2,1))
>>     f.barchart(a ~ b, data = x, groups = c)
>>
>> Which results in the following error being thrown:
>>
>>     ..3 used in an incorrect context, no ... to look in
>
> Regards,
> Tom
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>



-- 
Felix Andrews / 安福立
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The Australian National University
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