En Sun, 08 Mar 2009 20:08:32 -0200, Aaron Brady <castiro...@gmail.com>
escribió:
Hello,
I am creating a container. I have some types which are built to be
members of the container. The members need to know which container
they are in, as they call methods on it, such as finding other
members. I want help with the syntax to create the members.
Currently, the container has to be a parameter to the instantiation
methods. I want the option to create members with attribute syntax
instead.
Currently, I have:
cA= Container( )
obA= SomeType( cA )
obB= OtherType( cA, otherarg )
I want:
cA= Container( )
obA= cA.SomeType( )
obB= cA.OtherType( otherarg )
What are my options?
What about this? Doesn't require any kind of registration - the Container
just looks for any missing attribute in the global namespace.
py> from functools import partial
py>
py> class Container(object):
... def __init__(self):
... self.items = []
... def add(self, item):
... self.items.append(item)
... def __getattr__(self, name):
... if name in globals():
... return partial(globals()[name], self)
...
py> class SomeType(object):
... def __init__(self, parent):
... self.parent = parent
... self.parent.add(self)
...
py> class OtherType(SomeType):
... def __init__(self, parent, arg):
... SomeType.__init__(self, parent)
... self.x = arg
...
py> cA = Container()
py> obA = cA.SomeType()
py> obB = cA.OtherType(5)
py> print cA.items
[<__main__.SomeType object at 0x00B9E4B0>, <__main__.OtherType object at
0x00B9E890>]
P.S. The container and members are C extension types, not pure Python.
It's all implemented in __getattr__, so it should be easy to write the
equivalent C code. (I really don't know if __getattr__ maps to any
predefined slot in the type structure, or what)
--
Gabriel Genellina
--
http://mail.python.org/mailman/listinfo/python-list
