On Tue, Jan 20, 2009 at 2:39 PM, Luis Zarrabeitia <ky...@uh.cu> wrote:
> This line would make a lot more sense if you were talking about Java's getters
> and setters, or about a language where accessing a property is different than
> accessing an attribute (which would make little sense). If properties already
> let you change from attribute to method without affecting the caller, why do
> you
> need a property that does nothing?
My point exactly. Russ seems to agree with Python
but yet argue points for the sake of it. I'm not sure why :)
Having come from all kinda of programming backgrounds
and paradigms you learn to see the value in Python and the
kind of simplicity it has to offer. I will stand by my view
that there are many features of the traditional, strict
and academic features of the OO model that have little
practical value.
Python is a great mix of functional features, OO features
and has borrowed (what I believe) are the best of breed
features from all around.
One thing I find quite amazing is that we're having a discussion
over such low-level features of the OO model (and functional paradigm)
and how Python fits into it all ... And for what exactly ?
Russ - what is your point in all of this - You keep saying you don't have
time to waste with this - yet you keep making this thread grow
longer and longer and longer :)
As far as I'm concerned properties are just fancy functions to
retrieve and set attributes of an object. Consider the following
equivalent pieces of code:
#!/usr/bin/env python
from math import pi
class CircleA(object):
def __init__(self, radius):
self._radius = radius
self._area = pi * radius ** 2
def __getRadius(self):
return self._radius
def __setRadius(self, radius):
self._radius = radius
self._area = pi * radius ** 2
def __getArea(self):
return self._area
def __repr__(self):
return "<Circle r=%0.2f A=%0.2f>" % (self.radius, self.area)
radius = property(__getRadius, __setRadius)
area = property(__getArea)
class CircleB(object):
def __init__(self, radius):
self.radius = radius
self.area = pi * radius ** 2
def setRadius(self, radius):
self.radius = radius
self.area = pi * radius ** 2
def __repr__(self):
return "<Circle r=%0.2f A=%0.2f>" % (self.radius, self.area)
a = CircleA(1.5)
print a
a.radius = 2.0
print a
b = CircleB(1.5)
print b
b.radius = 2.0
print b
----------
http://codepad.org/tpyGNhrZ
I'll give you a hint which one I prefer :)
cheers
James
--
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