On Sep 8, 2009, at 12:39 , Simon Urbanek wrote:
On Sep 8, 2009, at 12:14 , Patrick Aboyoun wrote:
This is a reissue of a question I had asked a few weeks ago to see
if anyone had any thoughts on the matter.
I am looking to have slot in an S4 class definition that can take
any (S3 or S4) object. The ANY class seemed to be a good candidate,
but the is() function definition performs an S3Case test before
checking if methods:::.identC(class2, "ANY"). The result is the
is() function does not consider various S3 objects to be of class
ANY.
Yes, but how is that relevant to your question? A slot defined as
"ANY" will accept any type in R:
> setClass("foo",representation(a="ANY"))
[1] "foo"
> new("foo",a=factor())
An object of class "foo"
Slot "a":
factor(0)
Levels:
"ANY" is not an S4 class (and neither are various other types in R),
so is() correctly returns FALSE.
Ok, sorry, the last sentence is false - "ANY" is a virtual S4 class,
so it will return TRUE for S4 classes and FALSE for any other object.
Cheers,
Simon
> is(factor(), "ANY")
[1] FALSE
> is(lm(I(1:10) ~ rnorm(10)), "ANY")
[1] FALSE
> sessionInfo()
R version 2.10.0 Under development (unstable) (2009-09-07 r49613)
i386-apple-darwin9.8.0
locale:
[1] en_US.UTF-8/en_US.UTF-8/C/C/en_US.UTF-8/en_US.UTF-8
attached base packages:
[1] stats graphics grDevices utils datasets methods base
What is the recommended base "Object" class I should define my slot
to be so it can accept any object?
Patrick
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