The first example for learning-r.tumblr.com This is an example to show nested sources. The function "load.fun" is loaded in example001Setup.R, loads (and installs if not installed) ggplot2. At the same time, all of example001Setup.R is called within example001Plotting.R, meaning the only thing you have to do to set up your entire project is just run the first line of example001Plotting.R. (Then of course, you run lines 3 and 4 to attach the ggplot to a name, then plot it.)