Python number-like class that remembers arithmetic operations?

Question

I\'m wondering if there exists a python module that would allow me to do something like this:

x = MagicNumber()
x.value = 3
y = 2 * (x + 2) ** 2 - 8
print y          


        

Answer 1

>>> magic = lambda x: eval('2 * (x + 2) ** 2 - 8')
>>> magic(2)
24
>>> magic(3)
42
>>> magic = lambda x: eval('x ** 4')
>>> magic(2)
16
>>> magic(3)
81