fperez

#!/usr/bin/env python
"""
Interactive execution with automatic history, tries to mimic Mathematica's
prompt system. This environment's main features are:

- Numbered prompts (In/Out) similar to Mathematica. Only actions that produce
  output (NOT assingments, for example) affect the counter and cache.

- The following GLOBAL variables always exist (so don't overwrite them!):
  _p: stores previous result which generated printable output.