Another variant of what is probably the same issue:
> setClass("foo", representation(a = "numeric"))
[1] "foo"
> f <- function() x at a <<- 2
> x <- new("foo",a=1)
> y <- x
> f()
> x
An object of class ???foo???
Slot "a":
[1] 2
> y
An object of class ???foo???
Slot "a":
[1] 2
luke
On Wed, 31 Aug 2005, murdoch at stats.uwo.ca wrote:
> If I have an S4 object, and I make a copy, changes to the original
> aren't reflected in the copy:
>
> > setClass("foo", representation(slot="numeric"))
> > x <- new("foo", slot=1)
> > y <- x
> > x at slot <- 2
> > y
> An object of class "foo"
> Slot "slot":
> [1] 1
>
> This is as it should be. However, if I call the slot assignment
> function in a funny way, y *does* receive the changes:
>
> > x <- new("foo", slot=1)
> > y <- x
> > assign("x", "@<-"(x, "slot", 2))
> > y
> An object of class "foo"
> Slot "slot":
> [1] 2
>
> This happens in the current R-devel in Windows, and R-patched too.
>
> > version
> _
> platform i386-pc-mingw32
> arch i386
> os mingw32
> system i386, mingw32
> status Under development (unstable)
> major 2
> minor 2.0
> year 2005
> month 08
> day 31
> svn rev 35467
> language R
>
> Duncan Murdoch
>
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>
--
Luke Tierney
Chair, Statistics and Actuarial Science
Ralph E. Wareham Professor of Mathematical Sciences
University of Iowa Phone: 319-335-3386
Department of Statistics and Fax: 319-335-3017
Actuarial Science
241 Schaeffer Hall email: luke at stat.uiowa.edu
Iowa City, IA 52242 WWW: http://www.stat.uiowa.edu