The javacc parser (or more specifically the JavaCharStream class) has changed since bsh-2.0b5 and it appears that it can no longer handle arbitrarily sized input tokens. Previously the JavaCharStream implementation had working code that would expand the internal buffer as required, thus supporting arbitrarily sized tokens found in the input stream. It appears that in the switch from JavaCC to ParserGeneratorCC this capability no longer works. There is code in the class to increase the size of the internal buffer, however here is an example of a long string assignment that the current parser cannot handle:
parser1.bsh.txt