Re: [Rd] Attributes of 1st argument in ...
Hi Hadley,
My actual goal is to have a cbind method in the mondate package that behaves
just like the base cbind function: class and shape of the result, names,
etc. Perhaps it's due to the fact that 'cbind' uses its own internal
dispatching, but I have not found a way to implement a "true" S3-style cbind
method. (This is probably ancient news to the development team.) An S4 cbind
method will utilize callNextMethod with just setGeneric("cbind"), which has
no 'x' in the formal arguments. With no 'x', there's no "first argument" on
which to dispatch a "mondate" method. I can make the cbind of mondates also
be a mondate with an all-encompassing setMethod("cbind","ANY", etc) method,
but that wrests dispatch control from cbind which makes no sense whatsoever.
So, to make a long story even longer, I settled for a "cbindmondate
function" that utilizes the speed of base::cbind and (with one exception)
gives me the hoped-for "base cbind behavior."
I can send examples of my trial-and-error attempts under separate email if
you're interested.
Best regards,
Dan
On Sat, Jul 3, 2010 at 9:17 AM, Hadley Wickham wrote:
> Hi Dan,
>
> Is there a reason you can't change the function to
>
> f <- function(x, ...) {}
>
> ?
>
> Hadley
>
> On Fri, Jul 2, 2010 at 4:26 PM, Daniel Murphy
> wrote:
> > R-Devel:
> >
> > I am trying to get an attribute of the first argument in a call to a
> > function whose formal arguments consist of dots only and do something,
> e.g.,
> > call 'cbind', based on the attribute
> > f<- function(...) {get first attribute; maybe or maybe not call 'cbind'}
> >
> > I thought of (ignoring "deparse.level" for the moment)
> >
> > f<-function(...) {x <- attr(list(...)[[1L]], "foo"); if (x=="bar")
> > cbind(...) else x}
> >
> > but I feared my solution might do some extra copying, with a performance
> > penalty if the dotted objects in the actual call to "f' are very large.
> >
> > I thought the following alternative might avoid a potential performance
> hit
> > by evaluating the attribute in the parent.frame (and therefore avoid
> extra
> > copying?):
> >
> > f<-function(...)
> > {
> > L<-match.call(expand.dots=FALSE)[[2L]]
> > x <- eval(substitute(attr(x,"foo"), list(x=L[[1L]])))
> > if (x=="bar") cbind(...) else x
> > }
> >
> > system.time tests showed this second form to be only marginally faster.
> >
> > Is my fear about extra copying unwarranted? If not, is there a better way
> to
> > get the "foo" attribute of the first argument other than my two
> > alternatives?
> >
> > Thanks,
> > Dan Murphy
> >
> >[[alternative HTML version deleted]]
> >
> > __
> > R-devel@r-project.org mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-devel
> >
>
>
>
> --
> Assistant Professor / Dobelman Family Junior Chair
> Department of Statistics / Rice University
> http://had.co.nz/
>
[[alternative HTML version deleted]]
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Re: [Rd] Attributes of 1st argument in ...
Hi Dan,
Is there a reason you can't change the function to
f <- function(x, ...) {}
?
Hadley
On Fri, Jul 2, 2010 at 4:26 PM, Daniel Murphy wrote:
> R-Devel:
>
> I am trying to get an attribute of the first argument in a call to a
> function whose formal arguments consist of dots only and do something, e.g.,
> call 'cbind', based on the attribute
> f<- function(...) {get first attribute; maybe or maybe not call 'cbind'}
>
> I thought of (ignoring "deparse.level" for the moment)
>
> f<-function(...) {x <- attr(list(...)[[1L]], "foo"); if (x=="bar")
> cbind(...) else x}
>
> but I feared my solution might do some extra copying, with a performance
> penalty if the dotted objects in the actual call to "f' are very large.
>
> I thought the following alternative might avoid a potential performance hit
> by evaluating the attribute in the parent.frame (and therefore avoid extra
> copying?):
>
> f<-function(...)
> {
> L<-match.call(expand.dots=FALSE)[[2L]]
> x <- eval(substitute(attr(x,"foo"), list(x=L[[1L]])))
> if (x=="bar") cbind(...) else x
> }
>
> system.time tests showed this second form to be only marginally faster.
>
> Is my fear about extra copying unwarranted? If not, is there a better way to
> get the "foo" attribute of the first argument other than my two
> alternatives?
>
> Thanks,
> Dan Murphy
>
> [[alternative HTML version deleted]]
>
> __
> R-devel@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>
--
Assistant Professor / Dobelman Family Junior Chair
Department of Statistics / Rice University
http://had.co.nz/
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[Rd] bug in devPS.c
Hi there, I have filed a bug report at: https://bugs.r-project.org/bugzilla3/show_bug.cgi?id=14326. And the related patch is at: https://bugs.r-project.org/bugzilla3/attachment.cgi?id=1113 which will do: 1) correct the binary comment (the second line of PDF file) 2) remove a strange ^M in the PDF file 3) give correct font number for CID fonts when were used with default fonts. Regards, Jinsong __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
Re: [Rd] Attributes of 1st argument in ...
Hi Daniel,
On 02.07.2010, at 23:26, Daniel Murphy wrote:
> I am trying to get an attribute of the first argument in a call to a
> function whose formal arguments consist of dots only and do something, e.g.,
> call 'cbind', based on the attribute
> f<- function(...) {get first attribute; maybe or maybe not call 'cbind'}
>
> I thought of (ignoring "deparse.level" for the moment)
>
> f<-function(...) {x <- attr(list(...)[[1L]], "foo"); if (x=="bar")
> cbind(...) else x}
what about using the somewhat obscure ..1 syntax? This version runs quite a bit
faster for me:
g <- function(...) {
x <- attr(..1, "foo")
if (x == "bar")
cbind(...)
else
x
}
but it will be hard to quantify how this pans out for your unless we know how
many and what size and type the arguments are.
Cheers,
Olaf
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