R/mv.R

In mrdwab/mrdwabmisc: Miscellaneous R functions, mostly for data processing

#' Rename an Object in the Workspace
#' 
#' Renames an object in the workspace, "removing" the orinal object. This does
#' so without creating a copy of the original object. If an object in the
#' workspace currently exists with the new name specified, the function prompts
#' the user to verify that they want to overwrite that object before
#' proceeding.
#' 
#' 
#' @param currentName The current name of the object
#' @param newName The new name for the object
#' @author Rolf Turner
#' @references A good amount of discussion on when R makes a copy in memory in
#' this discussion thread:
#' \url{https://stat.ethz.ch/pipermail/r-help/2008-March/156028.html}.
#' @examples
#' 
#' x <- runif(1e7)
#' ls()
#' x.add <- tracemem(x)
#' mv(x, y)
#' identical(x.add, tracemem(y))
#' ls()
#' \dontshow{rm(x.add, y)}
#' 
#' @export mv
mv <- function (currentName, newName) {
  cnm <- deparse(substitute(currentName))
  nnm <- deparse(substitute(newName))
  if (!exists(cnm, where = 1, inherits = FALSE))
    stop(paste(cnm, "does not exist.\n"))
  if (exists(nnm, where = 1,inherits = FALSE)) {
    ans = readline(paste("Overwrite ", nnm, "? (y/n) ", sep =  ""))
    if (ans != "y") return(invisible())
  }
  assign(nnm, currentName, pos = 1)
  rm(list = cnm, pos = 1)
  invisible()
}