This is a somewhat more advanced example, containing
bison and lex scripts for a java source code parser.

Note that there is no python file containing a Parser class. We
have to generate one.

To do this, run:

 $ bison2py javaparser.y javaparser.l javaparser.py

or just:

 $ bison2py javaparser

You should now see a file javaparser.py

Then, just run the run-javaparser.py script. The
script will instantiate a parser and run it on the
whatever source file you give as an argument.