reflect.py

import math
class reflect(object):
    def __init__(self, fn=None, step = 0.01, start = 0, limit = None, threshold = 10.**(-3), args = []):
        self.fn = fn
        self.step = step
        self.n = start
        self.limit = limit
        self.threshold = threshold
        self.initial = args
        self.call = True if fn else False
    def __call__(self, fn=None):
        def __(fn=fn, once = False, args = []):
            if once:
                return fn(*(args+self.initial))
            n = self.n
            closest = (self.limit, fn(self.limit, *self.initial)) if self.limit else (0,0)
            while n<self.limit or not self.limit:
                k = fn(n, *self.initial)
                if abs(k-n) < closest[1]: closest = (n, abs(k-n))
                if abs(float(n) -float(k)) < self.threshold: return n
                n+=self.step
            return None, closest
        if self.call:
            return __(self.fn)
        return __
        

@reflect(start=0.01, step=0.00001, limit = 1.1)
def sin(n):
    return math.sin(n*2*math.pi)

print sin(), sin(once=True, args=[sin()]) #0.42922 0.430208613409

@reflect(start = 0.01, step = 0.00001, limit = 10, args = [3], threshold = 10.**-5)
def parabola(x, a):
    return a*x*(1-x)

print parabola(), parabola(args = [parabola()],once = True) #0.66667 0.6666633333