Sorry guys,
but I chose a really stupid name before (no "reference classes").
Hope it's okay to re-post.
Cheers,
Janko
>>> ORIGINAL MESSAGE <<<
Dear list,
Is it possible to update or reassign '.self' with an image of '.self'
(e.g. a locally stored .Rda file) from within a method?
I know that this might sound akward, but here's the use case:
1) Ref Class Definition
setRefClass(Class="Test",
fields=list(A="character", B="character"),
methods=list(importImage=function(path){
variable <- load(path)
expr <- paste("assign('", variable, "',", variable, ",
envir=.self)", sep="")
eval(parse(text=expr))
}
)
2) Initialize Method Definition
setMethod(
f="initialize",
signature=signature(.Object="Test"),
definition=function(
.Object,
path=NULL
){
obj <- callNextMethod(.Object)
if(!is.null(path){
obj$importImage(path=path)
}
return(obj)
}
3) Intended and "Extended" Use
Method 'importImage' was originally intended to read either an
object of name 'A' or 'B' from a respective path and overwrite the
respective fields in an obj of class 'Test'.
Now I wondered how I could "reassign"/update the object of class
'Test' itself by reading a respective .Rda image of an object of class
'Test' from within 'obj$importImage()'.
The way I've written 'importImage()', it did not work. Yet I wonder
if it's possible.
4) My Workaround (but I'm looking for something more elegantly)
In the class definition:
[...]
methods=list(importImage=function(path){
variable <- load(path)
if(variable != ".self"){
expr <- paste("assign('", variable, "',", variable, ",
envir=.self)", sep="")
eval(parse(text=expr))
return(TRUE)
} else {
return(.self)
}
})
[...]
In the initialize method:
setMethod(
f="initialize",
signature=signature(.Object="Test"),
definition=function(
.Object,
path=NULL
){
obj <- callNextMethod(.Object)
if(!is.null(path){
rslt <- obj$importImage(path=path)
if(!is.logical(rslt)){
obj <- rslt
}
}
return(obj)
}
Thanks for any comments,
Janko
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