title: Modular pattern in Google Apps Scripting
body: <p>I am building a GAS library using a modular pattern approach.
  As the main object is growing in size, I would like to split the code in separate files, to maintain a simple overview of the project.
  In the web editor, I can create additional scripts within my main script via File > New > Script file.
  Can I cross reference methods and variables from file to file? Do they share namespace?
  Is there a better approach to address this problem?</p>