ipython has a killer autoreload function: http://ipython.org/ipython-doc/stable/config/extensions/autoreload.html#module-IPython.extensions.autoreload http://ip

ipython has a killer autoreload function: http://ipython.org/ipython-doc/stable/config/extensions/autoreload.html#module-IPython.extensions.autoreload http://ipython.org/ipython-doc/stable/config/extensions/auto... In [1]: %load_ext autoreload In [2]: %autoreload 2 In [3]: from foo import some_function In [4]: some_function() Out[4]: 42 In [5]: # open foo.py in an editor and change some_function to return 43 In [6]: some_function() Out[6]: 43 It's nothing like a proper lisp repl, but you can sorta do this in vanilla python too, if you don't mind some annoyances. `reload` reloads a module: >>> import mymodule >>> print mymodule.myfunction() 3 >>> reload(mymodule) >>> print mymodule.myfunction() 5 Downside is you have to use the module, `from mymodule import function` won't reload.