similar to: the difference between UseMethod and NextMehod?

Hi, The 2 man pages give inconsistent description of class(): Found in ?class: If the object does not have a class attribute, it has an implicit class, ?"matrix"?, ?"array"? or the result of ?mode(x)? (except that integer vectors have implicit class ?"integer"?). Found in ?UseMethod: Matrices and arrays have class ?"matrix"?

(opening new bug report thread, on suggestion of BDR ..) I said on vaguely related topic: MM> There's another long-standing MM> UseMethod / NextMethod / Dispatch problem that I've never traced/solved.. MM> MM> Look at the $RHOME/tests/mode-methods.R file ! Peter Dalgaard already remarked : PD> ..i.e. this: PD> abc <- function(x, ...) { PD> if

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) }

>> 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, 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(...)

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

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

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

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

Dear, I'm looking for some examples on OO programming in R. I have the programming manual with explanation on UseMethod and NextMethod but I miss some practical examples to get me going (I hope). I searched the web but could not find a good independent tutorial on this. Any suggestions are welcome, Kris -- ------------------------------------------------------------------------

Hi! I have implemented class specific behaviour of "[[<-.myclass"<-function(). How it is posible to call the "[[.default" on an object of myclass? Eryk Dipl. bio-chem. Eryk Witold Wolski @ MPI-MG Dep. Vertebrate Genomics Ihnestrasse 73 14195 Berlin 'v' tel: 0049-30-84131285 / \ mail: wolski@molgen.mpg.de ---W-W----

Consider: foo <- function(x, y, ...) { UseMethod("foo") } foo.default <- function(x, y = 0, ...) { cat(sprintf("%s: x=%s, y=%s\n", as.character(match.call()[[1L]]), x, y)) if (...length()) str(list(...)) } foo.C <- function(x, y = 3, ...) { cat(sprintf("%s: x=%s, y=%s\n", as.character(match.call()[[1L]]), x, y)) if (...length())

On Tue, 14 May 2019 at 12:31, Pavel Krivitsky <pavel at uow.edu.au> wrote: > > > Note that disabling name-based dispatch implies two things: 1) the > > inability to override your method by defining gen.formula in the > > global environment, and 2) another package can break yours (i.e., > > internal calls to gen()) by registering an S3 method for gen() after >

Dear all, I have define a function and its methods as follows: ######## beginning of code fn <- function(x,...){ UseMethod("fn") } fn.foo1 <- function(x, commonA=1, ...){ print("fn.foo1 is called.") } fn.foo2 <- function(x, uniqueFoo2, common=1, ...){ ## uniqueFoo2 is a unique argument in fn.foo2 x <- uniqueFoo2; class(x) <- "foo1" ## use uniqueFoo2

Dear R developers, I will ask a very straightforward question concerning UseMethod's future, because people depending on my code wonder what will happen to it next. In R v2.0.1 NEWS it says o The undocumented use of UseMethod() with no argument is now formally deprecated. and in the R v2.0.1 help(UseMethod) it says 'UseMethod' accepts a call with no arguments and tries to

On Sat, 18 May 2019 at 23:34, Pavel Krivitsky <pavel at uow.edu.au> wrote: > > > The issue here is that you are registering a non-standard name > > (.gen.formula) for that generic and then defining what would be the > > standard name (gen.formula) for... what purpose? IMHO, this is a bad > > practice and should be avoided. > > The situation initially arose

I don't think there's any valid reason for this behaviour, i.e. it's a bug. For those who haven't read closely, the bug is that in the `foo(c)` call, within foo.default() the value of `c` is bound to both x and to the first element of ... . The 2012 thread you link to started with a slightly different setup and arguments were made by Simon that the behaviour is documented, but

match the argument 'x' if there is another argument with prefix 'x' Full_Name: Henrik Bengtsson Version: 1.3.1 OS: Sun Solaris 8 Submission from: (NULL) (130.235.3.49) I ran into a strange problem with UseMethod(). Run the following code: foo.Bar <- function(this, x=0, xidx=0) { cat("In foo.Bar(): ", this, ", x=", x, ", xidx=", xidx,

If I do > example(lm) ... > mycoef <- function(object, ...) UseMethod("coef", object) > mycoef(lm.D9) Error in mycoef(lm.D9) : no applicable method for "coef" which is pretty surprising, as coef has a default method. After a bit of digging, this comes from do_usemethod having defenv = environment where the generic was defined */ defenv =

tl;dr: S3 lookup no longer works in custom non-namespace environments as of R 3.6.1. Is this a bug? I am implementing S3 dispatch for generic methods in environments that are not packages. I am trying to emulate the R package namespace mechanism by having a ?namespace? environment that defines generics and methods, but only exposes the generics themselves, not the methods. To make S3 lookup work