Georg Brandl wrote:
> In my opinion property isn't really meant to be used as a decorator since
> it's impossible to create a read-write property. The decorator pattern
> doesn't really fit here.
>
I agree that property isn't currently intended to be used as a decorator,
but it isn't actually *impossible* to create a read-write property using
decorators. Here is one way:
--------- props.py ----------------
from inspect import getouterframes, currentframe
import unittest
class property(property):
@classmethod
def get(cls, f):
locals = getouterframes(currentframe())[1][0].f_locals
prop = locals.get(f.__name__, property())
return cls(f, prop.fset, prop.fdel, prop.__doc__)
@classmethod
def set(cls, f):
locals = getouterframes(currentframe())[1][0].f_locals
prop = locals.get(f.__name__, property())
return cls(prop.fget, f, prop.fdel, prop.__doc__)
@classmethod
def delete(cls, f):
locals = getouterframes(currentframe())[1][0].f_locals
prop = locals.get(f.__name__, property())
return cls(prop.fget, prop.fset, f, prop.__doc__)
class PropTests(unittest.TestCase):
def test_setgetdel(self):
class C(object):
def __init__(self, colour):
self._colour = colour
@property.set
def colour(self, value):
self._colour = value
@property.get
def colour(self):
return self._colour
@property.delete
def colour(self):
self._colour = 'none'
inst = C('red')
self.assertEquals(inst.colour, 'red')
inst.colour = 'green'
self.assertEquals(inst._colour, 'green')
del inst.colour
self.assertEquals(inst._colour, 'none')
if __name__=='__main__':
unittest.main()
-----------------------------------
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