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    <p>Something like this?</p> <pre><code>import operator MAKE_BINARY = lambda opfn : lambda self,other : BinaryOp(self, asMagicNumber(other), opfn) MAKE_RBINARY = lambda opfn : lambda self,other : BinaryOp(asMagicNumber(other), self, opfn) class MagicNumber(object): __add__ = MAKE_BINARY(operator.add) __sub__ = MAKE_BINARY(operator.sub) __mul__ = MAKE_BINARY(operator.mul) __div__ = MAKE_BINARY(operator.div) __radd__ = MAKE_RBINARY(operator.add) __rsub__ = MAKE_RBINARY(operator.sub) __rmul__ = MAKE_RBINARY(operator.mul) __rdiv__ = MAKE_RBINARY(operator.div) def __neg__(self, other): return UnaryOp(self, lambda x : -x) @property def value(self): return self.eval() class Constant(MagicNumber): def __init__(self, value): self.value_ = value def eval(self): return self.value_ class Parameter(Constant): def __init__(self): super(Parameter, self).__init__(0.0) def setValue(self, v): self.value_ = v value = property(fset=setValue, fget=lambda self: self.value_) class BinaryOp(MagicNumber): def __init__(self, op1, op2, operation): self.op1 = op1 self.op2 = op2 self.opn = operation def eval(self): return self.opn(self.op1.eval(), self.op2.eval()) class UnaryOp(MagicNumber): def __init__(self, op1, operation): self.op1 = op1 self.operation = operation def eval(self): return self.opn(self.op1.eval()) asMagicNumber = lambda x : x if isinstance(x, MagicNumber) else Constant(x) </code></pre> <p>And here it is in action:</p> <pre><code>x = Parameter() y = 2*x*x + 3*x - x/2 x.value = 10 print y.value # prints 225 x.value = 20 print y.value # prints 850 # compute a series of x-y values for the function print [(x.value, y.value) for x.value in range(5)] # prints [(0, 0), (1, 5), (2, 13), (3, 26), (4, 42)] </code></pre>
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    1. POPython number-like class that remembers arithmetic operations?
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    1. COIs there such a class? Paul: "Now there is!". I wish I had more upvotes.
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    2. COAmazing solution!
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    3. COI stand on the shoulders of a giant, er, Python? (Do Pythons have shoulders?)
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