How can I make Python/Sphinx document object attributes only declared in __init__?

andybuckley picture andybuckley · Oct 18, 2010 · Viewed 8.4k times · Source

I have Python classes with object attributes which are only declared as part of running the constructor, like so:

class Foo(object):
    def __init__(self, base):
        self.basepath = base

        temp = []
        for run in os.listdir(self.basepath):
            if self.foo(run):
                temp.append(run)
        self.availableruns = tuple(sorted(temp))

If I now use either help(Foo) or attempt to document Foo in Sphinx, the self.basepath and self.availableruns attributes are not shown. That's a problem for users of our API.

I've tried searching for a standard way to ensure that these "dynamically declared" attributes can be found (and preferably docstring'd) by the parser, but no luck so far. Any suggestions? Thanks.

Answer

S.Lott picture S.Lott · Oct 18, 2010

I've tried searching for a standard way to ensure that these "dynamically declared" attributes can be found (and preferably docstring'd) by the parser, but no luck so far. Any suggestions?

They cannot ever be "detected" by any parser.

Python has setattr. The complete set of attributes is never "detectable", in any sense of the word.

You absolutely must describe them in the docstring.

[Unless you want to do a bunch of meta-programming to generate docstrings from stuff you gathered from inspect or something. Even then, your "solution" would be incomplete as soon as you starting using setattr.]

class Foo(object):
    """
    :ivar basepath:
    :ivar availableruns:
    """
    def __init__(self, base):