[Rd] ggplot2: Add '+' operator for aes (uneval) objects

[Brian G. Peterson]

This seems like a conversation to have with the package's maintainer 
(Hadley), as suggested by the posting guide:

http://www.r-project.org/posting-guide.html
"If the question relates to a contributed package , e.g., one downloaded 
from CRAN, try contacting the package maintainer first."

and not R-devel.

Regards,

Brian

On 11/04/2013 03:54 AM, Thaler,Thorn,LAUSANNE,Applied Mathematics wrote:
> Dear all,
>
> Is there a reason, why there is no +-operator for aes (i.e. uneval) objects (as there is for themes and gg objects)? I had a couple of cases where such an operator would be useful, for instance to combine the result of aes and aes_string in functions. Any flaws with the following proposition:
>
>   `+.uneval` <- function(e1, e2) {
>    dup <- names(e1) %in% names(e2)
>    if (any(dup)) {
>      duplist <- paste(sQuote(names(e1)[dup]), collapse = ", ")
>      msg <- sprintf(ngettext(length(dup),
>                     "element %s occurs in both summands - second one gets precedence",
>                     "elements %s occur in both summands - second one gets precedence"),
>                     duplist)
>      warning(msg, domain = NA)
>    }
>    res <- c(e1[!dup], e2)
>    class(res) <- "uneval"
>    res
> }
>
> Any thoughts on that?
>
> Kind Regards,
>
> Thorn Thaler
> NRC Lausanne
> Applied Mathematics