And keeping it all in one text file. org-mode allows you to easily enough set up a structure so that it remains easy to edit.
# memoized fibonacci function
fibtable = {1:1, 0:1}
def fib (n):
global fibtable
if n in fibtable.keys():
return fibtable [n]
val = fib (n-1) + fib (n-2)
fibtable [n] = val
return val