Hullo all,
[***recap of the question: passing bar=harry fails when bar is among
the ... args.]
callTimes <- function(tom, harry) {
timesDefineInside(foo=tom, bar=harry
}
timesDefineInside <- function(foo, ...) {
foo * bar
}
callTimes(3, 4)
# Error: object "bar" not found
[***end recap]
On 20/10/2008, hadley wickham <[EMAIL PROTECTED]> wrote:
> Why don't you want to do this?
>
> timesDefineInside <- function(foo, bar...) {
> foo * bar
> }
You're right that's it the obvious solution — the thing is, I'm
hacking on somebody else's function, and in the interim I want to
maintain backward compatibility. Part of that is expecting the same
set of formals, so any extra arguments (in this case, 'bar' is
actually 'experimentalMode') have to come throught the dots.
Kaom Te wrote:
> Try this for timesDefineInside:
> timesDefineInside <- function(foo, ...) {
> extra.args <- list(...)
> bar <- extra.args$bar
> foo * bar
> }
Ah, that works! Apparently, there's a difference between
list(...) and
match.call(expand.dots=FALSE)$... # wrapped in eval() or not.
That makes sense, though, as the first will have evaluated bar=harry
at the moment of calling, within the calling function, while the
second will evaluated bar=harry within the called function. I think.
Thank you both very much; and thanks, too, to Martin Morgan, who
replied off-list pointing me at
bar <- eval.parent(match.call()$bar)
.
Grateful regards,
Sietse
Sietse Brouwer
--
Sietse Brouwer -- [EMAIL PROTECTED] -- +31 6 13456848
Wildekamp 32 -- 6721 JD Bennekom -- the Netherlands
MSN: [EMAIL PROTECTED] -- ICQ: 341232104
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