Comparing Code between Python, Java, and Perl

Here are the overlaps:

  1. The languages are general purpose.
  2. Can do object oriented programming.
  3. Can run unit tests.
  4. Can be run at the command line

It should be possible to write and rewrite programs until they pass the same tests and run the same way at the command line.  It can be done, and these pair-wise match-ups provide the details.