[R] "<<-" assignment no long work in class methods

[Witold Eryk Wolski]

Gang Liang wrote:

>Hi-
>
>I used to use "<<-" to do assignment inside a class method, and
>just found that now it is broken in R 2.0. For example, the
>following code
>
>-----------------------------------------------------------------------
>setClass( "myclass", representation(x="numeric") )
>setGeneric("incrXByOne", function(obj) standardGeneric("incrXByOne"))
>setMethod( "incrXByOne", "myclass", function(obj) obj at x <<- obj at x + 1 )
>
>  
>
Hi,

What (my guess) you want to define is:

setMethod( "incrXByOne", "myclass", function(obj) {obj at x <- obj at x + 1;obj})

You do not need "<<-" to assign to a function argument? Its in my view 
even erroneous.

This S code gives an error too.

test <- function(x)
{
x$bla<<-x$bla + 1
}
test(1)
Error in test(1) : Object "x" not found

/E

>incrXByOne( new("myclass") )
>-----------------------------------------------------------------------
>
>will give an error message like:
>
>   Error in incrXByOne(new("myclass")) : Object "obj" not found
>   ## R failed to trace the object back to the GlobalEnv...
>
>It used to work under R1.7 - 1.9. I don't know whether this is a
>bug or a new feature...
>
>Anyone can recommend a workaround?
>
>Thanks, Gang
>
>-----------------------------
>debian unstable, kernel 2.6.8
>
>  
>
>>version
>>    
>>
>
>platform i386-pc-linux-gnu
>arch     i386
>os       linux-gnu
>system   i386, linux-gnu
>status
>major    2
>minor    0.0
>year     2004
>month    10
>day      04
>language R
>
>______________________________________________
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>PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
>
>  
>


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Dipl. bio-chem. Witold Eryk Wolski
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