On Nov 27, 9:20 am, Roy Smith <[EMAIL PROTECTED]> wrote:
> In article <[EMAIL PROTECTED]>,
> Bruno Desthuilliers <[EMAIL PROTECTED]>
>
>
>
> wrote:
> > Steven D'Aprano a écrit :
> > > On Mon, 26 Nov 2007 21:48:36 +0100, Ton van Vliet wrote:
>
> > >> On Mon, 26 Nov 2007 20:14:50 +0100, Bruno Desthuilliers
> > >> <[EMAIL PROTECTED]> wrote:
>
> > >>>> However, I was more thinking in terms of attributes only
> > >>> Too bad : in Python, everything's an object, so 'methods' are attributes
> > >>> too.
> > >> Right, but I'm sure *you* know a way to distinguish between them
>
> > Yes : reading the doc. But that's something the compiler will have hard
> > time doing.
>
> > >> (I'm
> > >> just a beginner ;-)
>
> > > All methods are attributes. Not all attributes are methods. The usual way
> > > to see if something is a method is to try calling it and see what
> > > happens, but if you want a less informal test, try type():
>
> > >>>> type(''.join)
> > > <type 'builtin_function_or_method'>
> > >>>> type(Foo().foo) # with the obvious definition of Foo
> > > <type 'instancemethod'>
>
> > Fine. Now since Python let you define your own callable types and your
> > own descriptors, you can as well have an attribute that behave just like
> > a method without being an instance of any of the method types - so the
> > above test defeats duck typing. And since you can have callable
> > attributes that are definitively not methods, you can't rely on the fact
> > that an attribute is callable neither.
>
> If you want to have a little fun:
>
> class peverse:
> def __call__(self):
> raise AttributeError ("peverse instance has no __call__ method")
>
> x = peverse()
> x()
Horrific cluge:
--
def noself(func):
def t(*args, **kwargs):
self = args[0]
g = globals()
delete = []
for varname in dir(self):
if not varname.startswith("__") and varname not in g:
g[varname] = self.__getattribute__(varname)
delete.append(varname)
func(*args, **kwargs)
for varname in delete:
del(g[varname])
return t
class Test(object):
x = 1
@noself
def test(self):
print x
>>> foo = Test()
>>> foo.test()
1
--
FTR, I won't be using this :) I do like this syntax though:
class Vector:
def __init__(self, x, y, z):
self.x = x
self.y = y
self.z = z
def abs(self):
using self:
return math.sqrt(.x*.x + .y*.y + .z*.z)
Iain
--
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