R devel - Nov 2013 - ggplot2: Add '+' operator for aes (uneval) objects

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

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