Hi,
On Tue, Sep 13, 2011 at 1:54 PM, Joseph Park <jpark...@att.net> wrote:
>
> Hi, I'm looking for some guidance on whether to use
> S4 or Reference Classes for an analysis application
> I'm developing.
> I'm a C++/Python developer, and like to 'think' in OOD.
> I started my app with S4, thinking that was the best
> set of OO features in R. However, it appears that one
> needs Reference Classes to allow object methods to assign
> values (other than the .Object in the initialize method)
> to slots of the object.
> This is typically what I prefer: creating an object, then
> operating on the object (reference) calling object methods
> to access/modify slots.
> So I'm wondering what (dis)advantages there are in
> developing with S4 vs Reference Classes.
> Things of interest:
> Performance (i.e. memory management)
> Integration compatibility with R packages
> ??? other issues
I actually don't have much experience with Reference Classes and
(most) all of my R OO(P|D) with S4 (since I'm generally playing w/
bioconductor stuff, which has an S4 mandate).
I'm not sure exactly what you are after, but the way I design many of
my classes to enable them to have *some* pass by reference semantics
is to add a slot of type `environment` to the class def, like so:
setClass("Something",
representation=representation(x='numeric', cache='environment'),
prototype=prototype(x=numeric(), cache=new.env()))
Anything that gets put in `cache` is "passed by ref" so to speak. Consider this:
R> s1 <- new("Something", x=10)
R> s1@cache$by.reference <- 'there can be only 1'
R> s2 <- s1
R> s2@x
[1] 10
R> s2@x <- 12
R> s2@x
[1] 12
R> s1@x
[1] 10
R> s1@cache$by.reference
[1] "there can be only 1"
R> s2@cache$by.reference <- 'and then there were 2'
R> s2@cache$by.reference
[1] "and then there were 2"
R> s1@cache$by.reference
[1] "and then there were 2"
Proceed with caution ...
HTH,
-steve
--
Steve Lianoglou
Graduate Student: Computational Systems Biology
| Memorial Sloan-Kettering Cancer Center
| Weill Medical College of Cornell University
Contact Info: http://cbio.mskcc.org/~lianos/contact
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