R/get_obj.R

In shug0131/cctu: In-house Functions for Report Writing at Cambridge Clinical Trials Unit

#' Gets copies of objects from parent environments, or returns alternative if not found
#'
#' @param name text string of an object to find
#' @param alt an alternative to return if the object is not found
#'
#' @return either a copy of the object \code{name} or an alternative if it does not exist
#' @details this is designed to use within functions in the library to access global objects,
#' but provide a route to avoid hard-coding specific variable names in. It is not exported.
#'
#' @keywords internal
#' @examples
#' library(cctu)
#' rm(PATH)
#' cctu:::get_obj("PATH")
#' cctu:::get_obj("PATH", alt=getwd())
#' PATH <- "C:/MyFile"
#' cctu:::get_obj("PATH")
#' cctu:::get_obj("PATH", alt=getwd())



get_obj <- function(name, frame=parent.frame(), alt=NULL){

  if(exists(name,where=frame)){
    #this searches upwards into enclosing frames
    get(name, pos=frame)
  } else{
    warning(paste(name, "not found"))
    alt
  }
}