c166d750 |
import functools
def memoize(func):
_cache = {}
class NULL:pass
NULL = NULL()
@functools.wraps(func)
def _inner(*args, **kwargs):
_kwargs = tuple(
(k, tuple(v) if hasattr(v, '__iter__') else v) for k,v in kwargs
)
value = _cache.get((args, _kwargs), NULL)
if value is NULL:
value = func(*args, **kwargs)
_cache[(args,_kwargs)] = value
return value
_inner.__enter__ = lambda *_: _inner
_inner.__exit__ = lambda *_: _cache.clear()
_inner.reset = _cache.clear
_inner.cache = _cache
_inner.orig = func
return _inner
class return_if(object):
def __init__(self, map):
self._map = dict(
(tuple(k) if hasattr(k, '__iter__') else (k,),v) for k,v in map.iteritems()
)
self._func = lambda x:x
def _inner(self, *args):
if args in self._map: return self._map[args]
else: return self._func(*args)
def __call__(self, func):
self._func = func
return self._inner
@memoize
@return_if({1: 1})
def fact(n):
return n*fact(n-1)
@return_if({(1,1): 2, (2,2): 3, (3,3):4})
def sum(a,b):
return a+b
@memoize
@return_if({1: 1,2: 1})
def fib(n):
if n < 1: raise ValueError, "not n >= 1"
else:
return fib(n-1) + fib(n-2)
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