Function to make reusing R scripts easier

import.R

#' Imports a python style module.  These are just files with .R/r extensions.
#' 
#' If src is an R file, it is used directly.  Otherwise the directories in searchDirs are searched for an R file named as \code{src}.  The file is loaded into an environment that is stored in the callers environment.
#'
#' @param src File to load or name of module in search path.
#' @param as What to name the loaded module.
#' @param all Load all entries into parent namespace.  Use with caution.
#' @param searchDirs Directories to search for module.
#' @param reattach If module is already loaded with all=TRUE, re-attach it.
import = function(src,as=NULL,all=FALSE,searchDirs=.modPaths,reattach=TRUE){
  #Force it to be a character
  src = as.character(substitute(src))
  #Make a new environment for the src file
  module = new.env()
  #Get the thing
  if(!file.exists(src)){
    #Try and find the thing in each of the search paths
    found=FALSE
    for(searchDir in searchDirs){
      if(file.exists(file.path(searchDir,sprintf('%s.r',src)))){
        src = file.path(searchDir,sprintf('%s.r',src))
        found=TRUE
        break
      }else if(file.exists(file.path(searchDir,sprintf('%s.R',src)))){
        src = file.path(searchDir,sprintf('%s.R',src))
        found=TRUE
        break
      }
    }
    if(!found)
      stop(sprintf("Could not find module %s on search path.",src))
  }
  #Load it into our new environment
  sys.source(src,envir=module,keep.source=interactive())
  #Work out what to call it
  if(is.null(as))
    as=gsub('\\.[Rr]$','',basename(src))
  #Now do the assignment
  if(all){
    nom = sprintf("module:%s",as)
    if(nom %in% search()){
      if(reattach){
        detach(pos=match(nom,search()))
      }else{
        stop(sprintf("A module named %s is already attached.",as))
      }
    }
    attach(module,pos=2,name=nom)
  }else{
    penv = parent.frame()
    assign(as,module,envir=penv)
  }
  invisible(NULL)
}