[Baypiggies] Trivial OOP pattern problem
dav9dg at gmail.com
Fri Jun 15 09:01:00 CEST 2012
Hmm, so I just tried to actually run this and for some
reason inspect.getmembers(cairo.Context, predicate=inspect.ismethod)
returns an empty list.
Here's my ugly workaround:
def wrapper(self, *args, **kwargs):
to_return = func(self, *args, **kwargs)
if to_return is None:
to_return = self
#for method_name, method in inspect.getmembers(cairo.Context,
for method_name, method in inspect.getmembers(cairo.Context):
if not method_name.startswith('__'):
setattr(cls, method_name, return_self_decorator(method))
Pretty sure this accomplishes what you wanted :).
On Thu, Jun 14, 2012 at 11:56 PM, David Ginsburg <dav9dg at gmail.com> wrote:
> The problem with this is if a method needs to return a value other than
> self, you break it.
> This is probably hacky, but you could accomplish what you want doing the
> import inspect
> import functools
> def make_chainable_context(cls):
> def return_self_decorator(func):
> def wrapper(self, *args, **kwargs):
> to_return = func(self, *args, **kwargs)
> if to_return is None:
> to_return = self
> return to_return
> return wrapper
> for method_name, method in inspect.getmembers(cairo.Context,
> setattr(cls, method_name, return_self_decorator(method))
> return cls
> class ChainableContext(cairo.Context):
> This way methods that return something other than None are not broken.
> On Thu, Jun 14, 2012 at 11:28 PM, Brian Palmer <bpalmer at gmail.com> wrote:
>> On Thu, Jun 14, 2012 at 10:52 PM, Ian Zimmerman <itz at buug.org> wrote:
>>> Isaac> Hi, Why do you need each of the methods to return the instance?
>>> Isaac> Can you just wrap the method calls in a function and return the
>>> Isaac> instance?
>>> I am not married to the idea of a wrapper class, but I don't understand
>>> what you propose instead. What would the example code look like under
>>> your scheme?
>> Your initial solution seems like it'd work:
>> class Wrap(object):
>> def __init__(self, ctx):
>> self.ctx = ctx
>> def __getattr__(self, name):
>> def myf(*args, **kwargs):
>> getattr(self.ctx, name)(*args, **kwargs)
>> return self
>> return myf
>> There are benefits to being less dynamic, but this might be good enough.
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