Ruby provides an automatic constant called DATA, which is an IO object that references all text in the current file under an __END__ token. I find it convenient to use the __END__ area to store all sorts of stuff, rather than have to worry about distributing separate files. The DATA constant is determined from whatever ruby believes $0 to be. It doesn't work inside of other required libraries, so you'll see stuff like this all the time: END = File.open( __FILE__ ).read.split( /^__END__/, 2 ).last It works, but it's more work than I want to do. Chunker solves this by parsing __END__ tokens for you, and making it available in the form of a 'DATA_END' constant. It installs this constant into the class that includes Chunker, so you can use it again and again, assuming you use a different file for each class. It also automatically parses out other things that look like tokens, so you can easily have multiple, distinct documents all embedded into the __END__ block.