On 12/7/06, Tim Hochberg <[EMAIL PROTECTED]> wrote:
> Let me throw out an examples of how this could look.
>
> @implements(sequence.__getitem__, sequence.__len__)
> class MySequence:
> #....
>
> @implements(mapping.__getitem__, mapping.keys, mapping.__len__)
> class MyMapping:
> #....
>
> #...
>
> # supports reads better than has_ability to me in this context.
> if supports(someobject, mapping.__getitem__):
> # do something
FWLIW, I like the concept of a ``supports()`` method like this, and I
think it shouldn't be too foreign to Python users syntactically. I'm
sure I've seen code like this before::
if hasattr(someobject, '__getitem__'):
# do something
And the only real difference between the ``hasattr()`` code and the
``supports()`` code is that the ``supports()`` code not only
guarantees the existence of the method, but guarantees that the method
conforms to the expected semantics.
For the sake of DRY, I'd prefer to see::
class MyMapping:
def mapping.__getitem__(self, key):
...
def mapping.__len__(self):
...
instead of::
@implements(mapping.__getitem__, mapping.__len__)
class MyMapping:
def __getitem__(self, key):
...
def __len__(self):
...
but since we don't have syntactic support for either of these variants
right now, I think what would be most helpful is a proof-of-concept
patch that worked something like::
class MyMapping:
def __getitem__(self, key):
...
def __len__(self):
...
implements(MyMapping, mapping.__getitem__, mapping.__len__)
STeVe
--
I'm not *in*-sane. Indeed, I am so far *out* of sane that you appear a
tiny blip on the distant coast of sanity.
--- Bucky Katt, Get Fuzzy
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