On 23 May 2011 19:16, Michael Foord wrote:

Hello all,

I'm looking at implementing __dir__ for a class (mock.Mock as it happens) to include some dynamically added attributes, the canonical use case according to the documentation:

http://docs.python.org/dev/reference/datamodel.html?highlight=__dir__#object...

What I would like to do is report all the "standard attributes", and then add any dynamically created attributes.

So the question is, how do I obtain the "standard list" (the list that dir would normally report in the absence of a custom __dir__ implementation)?

There is no object.__dir__ (despite the fact that this is how it is documented...) and obviously calling dir(self) within __dir__ is doomed to failure.

The best I have come up with is:

def __dir__(self): return dir(type(self)) + list(self.__dict__) + self._get_dynamic_attributes()

Better version which orders and removes duplicates: return sorted(set((dir(type(self)) + list(self.__dict__) + self._get_dynamic_attributes()))

This works (absent multiple inheritance), but it would be nice to just be able to do:

def __dir__(self): standard = super().__dir__() return standard + self._get_dynamic_attributes()

Moving the relevant parts of the implementation of dir into object.__dir__ would be one way to solve that.

All the best,

Michael Foord

--

http://www.voidspace.org.uk/

May you do good and not evil May you find forgiveness for yourself and forgive others May you share freely, never taking more than you give. -- the sqlite blessing http://www.sqlite.org/different.html

-- http://www.voidspace.org.uk/ May you do good and not evil May you find forgiveness for yourself and forgive others May you share freely, never taking more than you give. -- the sqlite blessing http://www.sqlite.org/different.html

Michael Foord writes:

Moving the relevant parts of the implementation of dir into object.__dir__ would be one way to solve that.

Sounds fine to me. Do file a bug report.