FWIW, the "implementation of Earley parsing that handles the epsilon case as given by Aycock et al" was implemented Python, as the library "SPARK" -
http://pages.cpsc.ucalgary.ca/~aycock/spark/ . For a while it was in the Python distribution, though under Parser, not Lib.
SPARK embedded the grammar in the docstring, which influenced the PLY parser to do the same.