Eric's Literate Programming (elp) is a system for doing Literate Programming. In other words, from a single source file (or set of files) it can produce both a formatted document describing a program and the actual source code files for that program. The aim is for the document to explain the program to humans, with each piece of code being kept with the text that explains it, in an order chosen to make the explanation understandable rather than in an order determined by the rules of the source code language.