Re: Writing to stdout and a log file

[Michael Hoffman]

Mike wrote:
I should've mentioned I want StdoutLog to subclass the 'file' type
because I need all the file attributes available.
You might use a surrogate pattern. Here's one I use for this kind of 
situation, where I want to subclass but that can't be done for some reason.

class SurrogateNotInitedError(exceptions.AttributeError):
    pass
class Surrogate(object):
    def __init__(self, data):
        self._data = data
    def __getattr__(self, name):
        if name == "_data":
            raise SurrogateNotInitedError, name
        else:
            try:
                return getattr(self._data, name)
            except SurrogateNotInitedError:
                raise SurrogateNotInitedError, name
I'll leave it as an exercise to the reader to make this work when 
self._data is actually a list of objects instead of a single object. 
You'll obviously need special logic for different methods, like write(), 
since for some of them you will want to call every object in self._data, 
and others only a single object.
--
Michael Hoffman
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