R help - Nov 2004 - "<<-" assignment no long work in class methods

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 )

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

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
>
>______________________________________________
>R-help at stat.math.ethz.ch mailing list
>https://stat.ethz.ch/mailman/listinfo/r-help
>PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html
>
>  
>

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