[Tutor] classproperty for Python 2.7 (read-only enough)

[Peter Otten]

Thomas Güttler wrote:

> I would like to have read-only class properties in Python.
> 
> I found this
> http://stackoverflow.com/questions/128573/using-property-on-classmethods
> But there are a lot of discussions of things which I don't understand.
> 
> I want to be a user of class properties, not an implementer of the
> details.
> 
> I found this: https://pypi.python.org/pypi/classproperty
> 
> But above release is more then ten years old. I am unsure if it's dead or
> mature.
> 
> I am using Python 2.7 and attribute getters would be enough, no attribute
> setter is needed.
> 
> My use case is configuration, not fancy algorithms or loops.

Like this?

$ cat classproperty.py
class classproperty(object):
    def __init__(self, fget):
        self.fget = fget
    def __get__(self, inst, cls):
        return self.fget(cls)


class Foo(object):
    FOO = 42
    @classproperty
    def foo(cls):
        return cls.FOO

print "Foo.foo =", Foo.foo
print "Foo().foo =", Foo().foo
$ python2 classproperty.py 
Foo.foo = 42
Foo().foo = 42