The passes options causes Interscript to process files more than once. This is sometimes necessary to get cross reference information right. The default is currently 1.
  python iscr.py --weaver=text --passes=2 example.pak
Interscript may stop before running the specified number of passes. It will do this if, and only if, every buffered disk file ("named_file_sink") would write an output the same as the existing file. In that case, it assumes further passes wouldn't change anything, and stops. This is called convergence.