I think it would help as well to list languages that have various levels of 'real repl' implementations. Wonder what modern (systems you can 'make money with') there are that support this. I know common lisp + smalltalk and worked with both and really liked them for these reasons. I miss this functionality all the time as it was far more efficient (to me!) than modern debuggers.
The article specifically stated that Python does not have a real Read-Eval-Print-Loop mechanism like Lisp or Smalltalk. For example, the Python REPL doesn’t go into a breakloop mechanism for undefined functions.
It's not about whether they make money. It's about whether you can do absolutely everything needed to build your program interactively by talking to it while it's while it's running.
