A generic dynamic programming decorator.

dynamic.py

#!/usr/bin/env python

# Generic Dynamic Programming Library
# Just throw @dynamic in front of any method
# to make it dynamic!

import hashlib

def dynamic(func):
    vals = {}
    
    def _dyn_func(*args, **kwargs):
        hashish = []
        for arg in args:
            hashish.append(hash(arg))
        for k,v in kwargs.iteritems():
            hash.append(hash(k))
            hash.append(hash(v))
        
        hashish_s = ''.join(str(h) for h in hashish)
        
        hash_s =  hashlib.sha256(hashish_s).hexdigest()
        
        if hash_s in vals:
            return vals[hash_s]
        else:
            value = func(*args, **kwargs)
            vals[hash_s] = value
            return value
    
    return _dyn_func

@dynamic
def fib(n):
    print "called on %d"  % n
    if n == 0 or n == 1:
        return 1
    else:
        return fib(n-1) + fib(n-2)
    

print fib(22)

# OUTPUT:
# called on 22
# called on 21
# called on 20
# called on 19
# called on 18
# called on 17
# called on 16
# called on 15
# called on 14
# called on 13
# called on 12
# called on 11
# called on 10
# called on 9
# called on 8
# called on 7
# called on 6
# called on 5
# called on 4
# called on 3
# called on 2
# called on 1
# called on 0
# 28657