Swoop is a library of Python objects for representing and manipulating Autodesk Eagle board, schematic, and library files used in designing printed circuit boards (PCBs). It parses an input Eagle file, creates a internal representation data structure that represents the file's contents, provides accessors and mutators to query, read, and modify those contents, and generates valid Eagle files as output.
Documentation is available here: http://nvsl.ucsd.edu/Swoop