Call by reference: Was: Object orientation?
On 22 Mar 2001, Peter Dalgaard BSA wrote:
"Henrik Bengtsson" <henrikb at braju.com> writes:
To reply to Yves Gauvreau question (Jan 24, 2001) about how to set values within function, it is possible to do without without using the "<<-" assignment operator or other nasty tricks. I had the same problem and I did a nasty workaround two weeks ago implementing the functionality of reference variables, but today I "ran into" the [R] help page for ".Alias". With .Alias one can immitate call by reference! Here is an example that shows how it works:
.....
set <- function(object, value) {
this <- .Alias(object);
this$value <- value;
return (invisible());
}
It may work, but I wouldn't think it is documented to do so and could easily get blown away by an internal change (and *I'm* not going to put checks in to ensure that it keeps working)!
Some of us talked about putting Usage: this function should not be used in the .Alias help page. It doesn't seem to have happened, but you get the idea. -thomas -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._