pushd / popd for R

Hi Folks,

I haven't gotten around to putting my R code in nice objects yet. So, my code is procedural, and it's nasty. It sources one script to the next, processing data, analyzing data, etc. As the scripts get run around the codebase, they often change their working directory. So, I wanted access to a bash-equivalent pushd and popd. I'll run these at the beginning and end of each script.

These are not battle-tested yet, and there's really no error-checking or redundancy in them. So, use with care, and they'll probably evolve over time. Feel free to add to them in the comments!

Enjoy!

#  push getwd() strings into a FIFO vector

dir_fifo = c()

pushd <- function(cd) {

    # usage: pushd("directory to change to")
    dir_fifo = append(dir_fifo, getwd(), 0)
    assign("dir_fifo", dir_fifo, envir = .GlobalEnv)
    setwd(cd)
}

popd <- function() {

    # usage: popd()
    setwd(dir_fifo[1])
    dir_fifo = dir_fifo[-1]
    assign("dir_fifo", dir_fifo, envir = .GlobalEnv)
}