class Matcher(object):
    def __init__(self, cls):
        self.cls = cls
    
    def __call__(self, *args):
        self.children = args
        return self

    def __getattr__(self, name):
        return Matcher(getattr(self.cls, name))
    
    def __repr__(self):
        return self.cls.__name__ + `self.children`

class Pattern(object):
    def __init__(self, namespace):
        self.namespace = namespace
    def __call__(self, func):
        names = func.func_code.co_names
        for name in names:
            try:
                cls = getattr(self.namespace, name)
                func.func_globals[name] = Matcher(cls)
            except:
                pass

        return func()

class Foo(object):
    class Test(object):
        class Omg(object):
            pass
    class Foo(object):
        pass
    class Bar(object):
        pass

@Pattern(Foo)
def testPattern():
    return \
    Test(
        Test.Omg(),
        Foo(),
        Bar()
    )

print testPattern