[Rd] Private Variables in R5-Classes possible?

Claus Jonathan Fritzemeier ClausJonathan.Fritzemeier at uni-duesseldorf.de
Tue Feb 21 12:07:24 CET 2012

Hi list,

is there a way to define some kind of private Variable?

I would like to prevent the user from manipulating fields on his own, in 
order to not destroy data structures.

The problem is, that as soon as the variable exists in the environment 
it is accessible via t$secret_value.

test <- setRefClass("test", fields=list(
secret = function(value){
cat("the function was called\n")
if(exists("secret_value", envir=.self at .xData)){
return(get("secret_value", envir=.self at .xData, inherits = F))
assign("secret_value", value=value, , envir=.self at .xData)
) )

 > t <- test$new()
 > t$secret
the function was called
 > t$secret_value
Error in envRefInferField(x, what, getClass(class(x)), selfEnv) :
"secret_value" is not a valid field or method name for reference class 
 > t$secret <- "Blub"
the function was called
 > t$secret_value
[1] "Blub"

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