changing local namespace of a function

[Michael Spencer]

> Alex Martelli wrote:
>> Hmmm, you do realize that wrapdict uses a lot of indirection while my
>> equivalent approach, just posted, is very direct, right?  To reiterate
>> the latter, and dress it up nicely too, it's
>>
>> class wrapwell(object):
>>     def __init__(self, somedict):
>>         self.__dict__ = somedict
>>

Bad mistake on my part, sorry!


Nick Coghlan wrote:
> ... a class that combined property access with the above...
>  
In a similar vein to Nick's solution:

class AutoProperty(object):
     def __init__(self, meth):
        self.meth = meth
        self.name = meth.__name__
        self.__doc__ = meth.__doc__
     def __get__(self, obj, cls):
         if isinstance(obj, cls):
             return obj.__dict__.setdefault(self.name, self.meth(obj))
         else:
             return self.__doc__
     # You could define __set__ and __del__ but they don't seem
     # necessary based on what you've said so far


class DataManipulator(object):
     def __init__(self, data):
         self.__dict__ = data

class Model(DataManipulator):
     def z(self):
         """x+y"""
         return self.x+self.y
     z = AutoProperty(z)

     def z1(self):
         """Or any other useful information"""
         return self.z + self.x
     z1 = AutoProperty(z1)

     # You could automate these calls to AutoProperty in a metaclass

  >>> a = {'x':1, 'y':2}
  >>> b = {'x':3, 'y':3}
  >>> d = Model(a)
  >>> d.z
3
  >>> d.z1
4
  >>> a
{'y': 2, 'x': 1, 'z': 3, 'z1': 4}
  >>> d=  Model(b)
  >>> d.z1
9
  >>> b
{'y': 3, 'x': 3, 'z': 6, 'z1': 9}
  >>>

Michael