[EMAIL PROTECTED] wrote:
> Hey, I have the following code that has to send every command it
> receives to a list of backends. Instead of:
>
> class MultiBackend(object):
> """Renders to multiple backends"""
>
> def __init__(self, backends):
> self.backends = backends
>
> def flush(self):
> for b in self.backends:
> b.flush()
>
> def draw(self):
> for b in self.backends:
> b.draw()
>
>
> I would like to write each method like:
>
> flush = multimethod()
>
> Is that possible using new-style classes?
Not without a custom metaclass or the method name passed explicitly to
multimethod(). Here's a simpler approach that works with both new and
classic classes:
"""
>>> class B(object):
... def __init__(self, name):
... self.name = name
... def draw(self, x, y):
... print "%s: draw(%s, %s)" % (self.name, x, y)
... def flush(self):
... print "%s: flush()" % self.name
>>> m = MultiBackend([B("alpha"), B("beta")])
>>> m.draw(1, 2)
alpha: draw(1, 2)
beta: draw(1, 2)
>>> m.flush()
alpha: flush()
beta: flush()
"""
from operator import attrgetter
class MultiBackend(object):
def __init__(self, backends):
self._backends = backends
def __getattr__(self, name):
get = attrgetter(name)
def multi(self, *args, **kw):
for b in self._backends:
get(b)(*args, **kw)
setattr(self.__class__, name, multi)
return getattr(self, name)
if __name__ == "__main__":
import doctest
doctest.testmod()
Peter
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