similar to: Documentation of S3 and S4 classes, inheritance

I am sure that I do not have the answer to your question - but I would like to add to your views regarding the S4-issue. I've been involved in the gRbase package for graphical modelling in R. The first version was implemented in S4 but now we have made a roll-back to using S3 methods. While, I can see that S3 is not really comprehensive enough for 'proper' object oriented

"[.ggobiDataset" <- function(x, ..., drop=FALSE) { x <- as.data.frame(x) NextMethod("[", x) } "[[.ggobiDataset" <- function(x, ..., drop=FALSE) { x <- as.data.frame(x) NextMethod("[[", x) } "$.ggobiDataset" <- function(x, ..., drop=FALSE) { x <- as.data.frame(x) NextMethod("$", x) } > class(x) [1]

Hi, I'm new to OOP in R so please forgive the naiveness of some of the questions. Here are a couple of them. It would be great if you can contrast to OOP in Java. 1. R's S4 appears to centered around a dispatch mechanism which in my understanding is just a way to implement polymorphism. Now, here's the snag, I thought polymorphism was an aspect of OOP not by itself the definition of

Hello,   ###  I created two classes "A" and "B". "A" is the superclass of "B".   setClass("A", representation(s1="numeric"),prototype=prototype(s1=8)) setClass("B",contains="A",representation(s2="character"),prototype=list(s2="hi")) myA=new("A") myB=new("B")   ####  I created

Dear UseRs, A simple class inheritance example: > setClass("test",representation(a="numeric")) > setMethod("initialize","test", function(.Object,x,...){ print("Initialization!!!") callNextMethod(.Object,a=x,...) }) > new("test",x=23) [1] "Initialization!!!" An

Dear R developers, Motivated by discussion about checking inheritance of S3 and S4 objects (in head matrix/array topic) I would light to shed some light on a minor gap about that matter in R C API. Currently we are able to check inheritance for S3 class objects from C in a robust way (no allocation, thread safe). This is unfortunately not possible for S4 classes. I would kindly request new

Matt Nelson <MNelson at sequenom.com> reported a problem using the Hmisc library that did not occur with versions of R before 1.6. I am running platform i686-pc-linux-gnu arch i686 os linux-gnu system i686, linux-gnu status major 1 minor 6.0 year 2002 month 10 day 01 language R > library(Hmisc) > g <-

Hi, although I've done S3 dispatching for more than a decade now, I think I managed to overlook/avoid the following pitfall when using NextMethod(): If you explicitly pass argument '...' to NextMethod(), you will effectively pass those argument twice to the "next" method! EXAMPLE: foo0 <- function(...) UseMethod("foo0"); foo1 <- function(...)

I have another problem with NextMethod. Not sure if its related to the last problem. In this example, we have a generic called ff with methods for AsIs and test classes. We call the generic with an object of AsIs class. The corresponding method adds 1 to it and then changes the class to test followed by issuing a NextMethod. However, that results in this error (using R 2.0.0, 2004-10-04

S Programming by Venables and Ripley (page 78) has the example listed at the end of this email. However, I get the following error when I try the example. I don't understand the descriptions of NextMethod on its help page. Could somebody let me know how to fix the error of this example? > test(x) c1 c2 Error in NextMethod() : no method to invoke Calls: test -> test.c1 -> NextMethod

The example is invoking NextMethod via an anonymous function, which is not allowed (see documentation for NextMethod). Normally one gets a runtime error "'NextMethod' called from an anonymous function", but not here as the anonymous function is called via do.call. I will fix so that there is a runtime error in this case as well, thanks for uncovering this problem. I

On 02/22/2018 12:07 PM, I?aki ?car wrote: > 2018-02-22 10:29 GMT+01:00 Tomas Kalibera <tomas.kalibera at gmail.com>: >> The example is invoking NextMethod via an anonymous function, which is not >> allowed (see documentation for NextMethod). > Thanks for your response. I definitely missed that bit. > >> Normally one gets a runtime >> error

Thank you Luke. That is why I don't use Rf_inherits but INHERITS which does not allocate, provided in the email body. I cannot do similarly for S4 classes, thus asking for some API for that. On Fri, Nov 1, 2019 at 5:56 PM Tierney, Luke <luke-tierney at uiowa.edu> wrote: > > On Fri, 1 Nov 2019, Jan Gorecki wrote: > > > Dear R developers, > > > > Motivated by

>> One clear moral seems to be don't do anything more inside a >> generic function than you really need to do. Keep it *very* >> simple indeed. >> > I recall JMC saying something like, all generic functions > should be one line long; a call to the appropriate UseMethod. It certainly is encouraging to know that others also have been confused by aspects of

Hi the list, I define a class 'C' that inherit from two classes 'A' and 'B'. 'A' and 'B' have no slot with similar names. ---------------- setClass( Class="C", contains=c("A","B") ) To define the get operator '[' for class "C", I simply use the get of "A" or "B" (the constante

A general goal for the next version of R is to make S4 and S3 play better together. As mentioned in a previous thread, one limitation has been that S3 generic functions, specifically the UseMethod() call, did not make use of S4 inheritance when dispatching on general S4 objects. This has been fixed in a version committed today (updated to rev 52267). The code change is not large, but it

Hi all, I'd like to ask if the following behavior is a bug. To me it certainly feels surprising, at the very least. In this example, I would like to call NextMethod() from my `child` object, have `cols` be left untouched, and then substitute(cols) in the parent method. It works when you use a `parent` object (as expected), but I would have also expected to get `mpg` back when calling it from

Is there any good source of information on how S4 classes (and methods) work from C? E.g., for reading how to read a slot value how to invoke a method how to test if you have an s4 object For writing, how to make a new instance of an S4 object. I've found scattered hints in the archive, including a link to a talk on this subject "I am using C code to create an S4 object based on

Hi all, Not sure if this belongs to R-devel or R-package-devel. Anyways... Suppose we have objects of class c("foo", "bar"), and there are two S3 methods c.foo, c.bar. In c.foo, I'm trying to modify the dots and forward the dispatch using NextMethod without any success. This is what I've tried so far: c.foo <- function(..., recursive=FALSE) { dots <-

My question is when the object argument of NexthMethod be used? In the following example, weather object argument is used will not affects the result. ### foo=function(x) {UseMethod("foo")} foo.cls1=function(x) { x=x+1;class(x)<-"ncls" NextMethod() } foo.ncls=function(x) { cat("ncls\n") } foo.cls2=function(x) { cat("cls2\n");print(x) }