On Wed, Nov 3, 2010 at 8:51 PM, Brett Calcott <[email protected]> wrote:
> On 4 November 2010 14:34, Robert Bradshaw <[email protected]>
> wrote:
>> On Wed, Nov 3, 2010 at 8:24 PM, Brett Calcott <[email protected]>
>> wrote:
>>> On 3 November 2010 19:24, Dag Sverre Seljebotn
>>> <[email protected]> wrote:
>>>> cdef class A:
>>>> cdef Vector obj
>>>> x = delegate_property(obj, 'x')
>>>>
>>>> or similar, without throwing in new syntax. But it may be too late and I
>>>> don't care too much. Remember that "x = property(...)" is already in
>>>> Python.
>>>>
>>>
>>> This looks like an interesting option, especially if it was possible
>>> to write your own reusable "xxxx_property" functions that did "the
>>> right thing" for the particular object/library being wrapped. This
>>> would remove a lot boilerplate code that is normally cut and pasted
>>> for setter/getter functions. So, in a case where the C++ members are
>>> private, but access is provided via camelcase set/get functions,
>>> instead of
>>>
>>> property value:
>>> def __get__(self):
>>> return self.obj.getValue()
>>> def __set__(self, int x):
>>> self.obj.setValue(x)
>>>
>>> We could write:
>>> x = camelcase_delegate_property(self.obj, 'value')
>>
>> The one thing that I don't like about this is putting the attribute in
>> a String.
>>
>
> Is this possible?
> x = member_property(self.obj.x)
> y = getset_property(self.obj.getY, self.obj.setY)
> (the names of these need work I agree)
>
> But I take it that the general idea would be able to roll your own
> when there was some repetitive thing you needed to do, so up to you
> what you passed.
>
> For example, the obj pointer in some of the classes I am currently
> wrapping can sometimes be set to NULL. So in many cases the property
> access needs to check that first, and raise an exception. If I could
> write my own getset_with_check_property(...), that would be very cool.
If you need more than something simple, is the
property x:
def __get__(self):
[some logic here]
return result
too verbose for you? We're not trying to be perl with magic one-liners.
- Robert
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