# Community Data Science Collective R Utilities
#
# Copyright (c) 2010-2016 Benjamin Mako Hill and Aaron Shaw 
# mako@atdot.cc, aaronshaw@northwestern.edu

# load a file if a variable is missing
load.if.missing <- function (var.name, file.name) {
  if (!exists(var.name)) {
    load(file.name, parent.frame())

    # check to see if we're dealing with a data.table because, if we
    # are, we need to do some nasty back and forth
    if (class(eval(as.name(var.name)))[1] == "data.table") {

      # gnarly function that loads resorts things within the parent
      # frame to get around the bug in data.table
      assign(var.name,
             data.table(as.data.frame(eval(as.name(var.name))),
                        key=attr(eval(as.name(var.name)), "sorted")),
             parent.frame())
    }
  }
}