Let me try again:
Suppose I have a central class with complex behavior that I want to
simply write as a bare skeleton upon which to hang the auxillary
classes that help provide the complex behavior.
The naive approach would be to write:
class Skeleton:
def __init__ (self):
self.core_data = 1
class Auxillary:
def __init__ (self):
pass
def string (self, skeleton):
return "%s %d" % (self.__class__.__name__, skeleton.core_data)
skeleton = Skeleton ()
auxillary = Auxillary ()
auxillary.behavior ()
What I will typically do is create the auxillary class as a friend so
that I can have tighter integration between the Skeleton instance and
an Auxillary member instance, where the Auxillary instance isolates
behavior that I might want to modify later through inheritance.
class Auxillary (Friend):
def __str__ (self):
return "%s %d" % (self.__class__.__name__, self.friend.core_data)
class Skeleton:
def __init__ (self):
self.auxillary = Auxillary (self)
skeleton = Skeleton ()
print skeleton.auxillary
See the difference? I know this is a bit contrived, but I wanted to
keep the effect simple. Effectively I now have a self-documenting
friend relationship between classes.
The Eternal Squire
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